Articles

DECWARE owner Steve Deckert's

Ramblings about hi-fi.

by Steve Deckert

A good article to start with is this one:

Why the SET & Efficient Speaker approach works

This is an original design log that was written during the development of the
Original Zen Triode Amplifier

August 1996

High Fidelity Engineering (Decware) has a clear focus that revolves around preserving
the forgotten past of hi-fi in the 1960s before it took a major step backwards from the perspective of sound quality. By that I mean that since the invention of non-discrete IC based solid-state receivers, overall sound quality has declined when compared to the older tube counterparts. Believing this gets harder and harder with each generation.
Kids don't know what records are, and they think tubes are light bulbs. And quite frankly, it is completely impossible to relate to the kind of sound quality I'm talking about unless you've been exposed to it. Kind of like a man trying to imagine what it must be like to be pregnant and give birth, something he'll never know... at least not in this lifetime.

If you're the average person with a stereo - even a fancy new surround-sound stereo then you enjoy the company of approximately 98% of all the people with stereos... and I'm sorry to say that presenting this amplifier in a way that you can grasp (because it goes against everything you know) may be no less complicated than a pregnant man.

The passion behind this idea for me comes from the desire to expose the common man owning the common stereo - to the magic of triodes, with a secondary objective of messing with the common audiophile who believes specifications are the 11th commandment. Someone should have done this long ago, but because of the unorthodox thinking required to pull off such a feat, I don't suppose other companies wanted to take the risk. For example, if I tried to market a 6 watt amplifier with around
10% distortion who would take it seriously?

An entry level " audiophile " amplifier that would be affordable to the masses has been my dream for many years now. To find a way to make it affordable and make it appeal to the average person is obviously the difficult part. The passion to do so comes from past personal frustrations of not being able to afford what I want and not being able to enjoy what I have because I've heard what I want! (been there haven't ya!) I can assure you most of us have a hard time justifying the crazy amount of money required to obtain a true high-fidelity system.

The general perception of an audio system to the masses is pretty much anything you could find at a " digital ready " electronics supermarket. Well guess what... the masses all have ears as good as any audiophile and the ability to appreciate the same things that result from high end listening. Those who've never been exposed to three-dimensional high fidelity can hardly be chastised for not appreciating the difference between the two, or for not being aware that there is a profound difference.

The science of sound and harmonic resonance is far and away the most complex and least understood science on earth, in my opinion. I would say that the monumental joint effort of all the people, and the equipment required to send up an Apollo mission would be simpler than building a perfect playback system. It takes significant effort in design and a significant quality in parts to achieve good sound. It should be pointed out that the HIGH-END audio market is oppressed with the monumental and expensive task of improving the high-fidelity playback system we commonly refer to as the " stereo " and that is why a respectable stereo system costs between 15 and $30,000.00 Gee, that's about the price of an automobile!

September 1996

My objective with this design is to get the absolute highest quality… harmonically in-tact sound in the hands of the wanna be audiophiles. My research and experience over the years has taught me that tube circuits are the way to obtain this objective. If I were designing this on paper with specifications in mind I would have chosen solid-state circuits. I really prefer the natural sound of tubes and while I have heard some solid-state solid-state amplifiers that I could enjoy, they start at about $7500.00.
The market is SATURATED with solid-state gear, and as I said, I don't feel it is the format necessary to complete this goal.

Up until this summer, I have been building Class A1 push-pull tube amplifiers of various designs with the intention of marketing one as the entry level amplifier. The part I've been wrestling with (like all small manufacturers) is keeping the cost down and yielding terrific sound quality. Success usually seems to go to those who have achieved the correct balance of compromise (understanding of course that everything in audio is a balance of compromise).

The push-pull tube amp designs seem to be the most popular because they can be fairly inexpensive to build, have plenty of power, and sound quite good when compared to mid-fi solid state gear. I really thought the answer could be found in a push-pull design for those reasons.

This summer while playing with single ended tube amplifier designs for my own personal stereo, I stumbled into some results that forced me to take a real second look at exactly what are watts? You know you read these ads for those five watt triode amplifiers that start at around $5,000.00 and go way up from there and wonder why would anyone pay that much for such a thing if it only has a few watts?

Lets just say some enlightenment from the audio spirits came upon me, and it was enough to realize that at a normal listening level, most of the musical content can be found in the first magical watt of power. I then realized that the priority in high-fidelity reproduction should be focused on that first watt. I have been trying to truly understand this for some time now, and in particular, been trying to define in my own research the reason why solid-state watts seem less than tube watts to the ear, yet equipment measurements would indicate that they are capable of achieving the same amplitudes.

Solid-state stereo gear has a tendency to sound thin, and quickly run out of headroom (clip) when pushed. Tube amps are very different. If you compare a 40 watt tube amp with a 100 watt solid state amp or receiver, the tube amp will put more music in the room, and get louder every time. You will find that at nominal listening levels, the loudness button is needed to get the solid-state amp to sound full-bodied, yet the tube amplifier sounded warm and full with a dead flat signal. This is a great example of how " watts " are not " watts " and a prelude to a secret only the most advanced audio gurus will share, and that is that specs in audio gear mean nothing.

Why is it that a 10 watt musical instrument amplifier such as a guitar amp will in real life (and on stage) get loud enough to split your brain in half, yet it seems to take mega bucks and major stereo gear with 100's of watts to reproduce the same sound in your living room, a room that remains a fraction of the size of a live performance? Perhaps it's because everyone is going about it wrong, confusing convenience with performance.

October 1996

Enough rattling on... Two weeks ago I completed prototyping the circuit for a single ended low power tube amplifier and have been listening to it ever since. The schematic is at the top of this page. At this stage I have already decided that this will be the chosen design for the project. The actual cost will decided by the cost of the output transformers. One of the main reasons single ended tube amps are so much higher in cost than their push-pull counter parts is that the output transformers are completely different. In a single ended design, the output transformer must be designed to handle the DC current at the bias point, so a special transformer must be used. It features an air gap that optimizes the coupling at low frequencies and the DC current that serves to lower the permeability of the core. Without the air gap, the iron will saturate under too little DC bias to accommodate the needs for a single ended triode. Too much gap will reduce primary inductance so that the lowest frequencies will not pass without attenuation.

All other things being equal, the output transformers (or IRON as I call it) has the final say in the resulting sound quality. When you're looking at different iron for a design, you find that the standard push-pull output transformers range in price between $75. and $400.00 ea. (per channel.) and you find the single ended output transformers range in price from $150. to 1200.00 ea. That BTW is why the single-ended stuff is so expensive.

I have a 50 watt (ea. channel) tube amplifier that I built up to a reasonably impractical extreme, and I have been using that as my personal reference piece. It powers an efficient pair of speakers in my main listening room (over 90dB) and in all honesty (with feedback off) sounds better than any other push pull amplifier I have compared it to. In fact, a version of it was my original idea for this project, and has been for years because I liked the sound so well…

My specific design goal has wavered a bit in the past months as I get ready to do this. If I am going to market a tube amp to people who have never had the joy of listening to one, and given the solid state, cranked up with the loudness on and tone controls engaged listening habits of those people, how should it sound? Do I go for power so it will stomp their past systems, or do I go for pleasure so it will reveal to them the inner levels of music? In other words, do I give them what they already have but just a lot better, or do I give them an opportunity to discover a magic in music that they are unaware of. It really gets into a psychology issue, one that I have pondered for almost 10 years now. From a business standpoint, I would make more money with the prior.

This is what happened... to completely solidify the decision. My new little single ended amplifier will run in either Pentode or Triode mode. In Pentode it benches 5.7 watts, and in Triode, it does 1.8 watts RMS pure class A per channel. Because of the front end, and additional gain stage in the design it is possible to get louder than you could ever believe is possible with 5.7 watts. Anyway, ever since I switched the little guy over to triode mode, I have not had any desire to switch it back. It is the most natural real sound I have ever heard in this house. And the eerie thing is that it achieves a nominal listening level high enough to be exactly the same listening level I have been accustomed to. That’s 1.8 watts Vs. 50 watts which is the same as a hundred watts or more in a solid-state receiver. The enormous improvement in quality has made this new little amp my full time personal listening amp. My good ol’ favorite just got bumped. As for the psychology issue, I will be going for the magic.
In my observations over the years the reason people turn the volume up to the levels they do, is to gain the effect of physically feeling the music. This effect is the motivating reason for turning it on, and this effect is the ONLY effect that the quality of equipment has to offer so it's no wonder. Once you have spent an evening with premium gear like this little triode amp, you find that the physical effect you were accustomed to happens sooner and at lower volumes because the even order harmonics are in-tact and free of odd order harmonics found in solid-state circuits. Then the big one hits you, another more profound EFFECT happens in addition to the physical effect -- emotional effect. So you have one that strokes your body, and one that caresses your inner self adding a new found joy to the experience of listening to your stereo.

November 1996

Having my strongest talent in speaker design I have thought long and hard about the statement: "Your speakers have the most effect on how your stereo will sound - replacing your speakers first gets the most improvement." Being a speaker designer the temptation to accept that has always been strong, however I have been slowly and consistently disproving that to myself year after year.

It is my opinion that the amplifier makes the most difference in the sound of your stereo and then your other electronics. I can safely say that your speakers are probably the least contributors to the sound rather than the most if your listening to good tube gear. If you gave me a choice of a good tube amp and a pair of Bose speakers or a mid fi solid state amp and a $24000.00 pair of speakers, I would choose the Bose and the tube amp because it would sound better.

paper001

A SINGLE ENDED TUBE AMP FOR THE MASSES

by Steve Deckert
August 1996

November 1996

If your not an amplifier builder this may become laborious reading after a while, but initially you should understand that the audiophile's fascination with sound stage and imaging (the motivating factor for all tweaks) is well supported in this design. I have found that the determining factors that map your systems sound stage and control imaging are mostly if not completely governed by impedance matching. Finding the exact right setting on your pre-amp volume control for best sound could be an example. When you break-up a pre-amp and amplifier into their respective gain stages and begin to play around with the input and output impedance of each you start to see why no two combinations of amplifier/pre amp will ever sound the same. This is the reason for the large concern about finding "good matches" in equipment and why some good gear sounds bad. To all "miserable" audiophiles that have found out the hard way that money alone can't solve the problem, I would say in fact that this is the problem.

This ability to tweak is what I feel it will take to win the hearts of the serious audiophile and what it will take to be compatible with the expectations of the solid state conditioned masses. This is not because it has millions of bells and whistles (and it doesn't) but because the operator will be able to "discover" the best sound by changing the configurations of the amplifier. It makes sure that whoever buys it is sheltered from the alternative which is taking your chances with odds of getting just the right impedance match between all of your components.

The schematic in figure 1 is what I have prototyped and am currently listening to. The final version will be very similar to this. As you can see the amplifier has 3 gain stages, or optionally two, depending on where you select to have the input go to. In the two stage (direct) mode, the single passes through one resistor and one capacitor the tubes and the output transformer. I'm sure you'll find merit in this "less is more" approach when you listen to it. The additional stage making this optionally an integrated amplifier for all practical purposes gives additional impedance balancing and more gain so that you can listen to it at louder volumes.

The tubes I am using are a 12AU7 and 12AX7 for the first two stages into a pair of 6BQ5's (EL84's) for the finals. I chose the single EL84 because it is a scaled down version of the popular EL34 but in my opinion has a better sound. The single EL84 uses less current which is making this amplifier a cost effective reality to build. I think it has better sound than larger tubes because the plates are small and tightly packaged around the screen grid meaning there is less distance for the flow of electrons between the two. The other tubes are perfect for this design because they are the most popular of their kind and the easiest to find. This means the guy that buys it can play musical tubes by trying several different brands without spending any real money.

The biggest feature will be the switch for changing the amplifier operation from Pentode to Triode. If you need more output, and like you music to sound a little analytical with better specs you can run it in pentode. If you want to here a slightly warmer more pure musical sound with less power switch it to Triode. Obviously there are several combinations you can get from combining the features of this amplifier each with its own sonic signature. You surely will be able to find one that you love.

The outputs on this amplifier will run most any impedance of loudspeaker, 6 to 8 ohms being ideal (at least with the current iron I plan to use). The outputs can bridged by strapping the positives of both channels together if you happen to have two of these and wanted to run them as mono amplifiers, one for each channel.

paper002

A SINGLE ENDED TUBE AMP FOR THE MASSES

Part II - The Design

Well I have pondered the chassis design for some time now. Not only from the perspective of cost and appearance, but from the resulting topology of all the parts. Things like heat and shielding become large considerations not unlike where the thing is intended to be placed in the room. Do you make it like a conventional tube amp and plop it down on the rug, or try to cram it into a more standard chassis like a 19" rack mount unit.

A unique opportunity with this little amp lies in the simple fact that it is so small. The 6BQ5 output tubes are not much larger than a normal preamp tube, and have nowhere near the heat of a larger output tube. Because of this and the size of the transformers I could build this into a nice rack mount chassis the size of an average preamp (3.5" high).

Okay, how to give the owner of this amplifier the satisfaction of hypnotically staring into the golden glow of the tubes... you know that's a must - too many people talk about it. I happen to be one of them. In fact I'm not sure sometimes if it's a vice or a gift, but I have a real hang-up with how things look. What followed was the all too familiar, slightly out of phase, molting period of several days when I walk around in circles a lot. Two days ago while I was meditating to music, (I was really enjoying some "FRESH AIRE" on American Gramophone being played on this amp) it hit me like a Zen Lightning Bolt in the forehead! An image of exactly what it should look like, how to lay out the entire parts topology, and flashes of it sitting in many different listening rooms blew into my head. I love it when that happens!

From that image I did this conceptual drawing of it exactly as it appeared. The picture can be seen in figure 1. The ventilation will be through the top and bottom center of the chassis. The tube topology will be horizontal opposing channels with the rectifier centered between them in the back of a shielded "room" inside the chassis. I'm not sure how cost effective this chassis would be, but I will definitely be building some.

NOTE: Now 2023, I can see the only reason this chassis didn't happen was money and resources. As it would turn out a small 10 x 6 x 2 inch steel box would half to work and the resulting amp would look absolutely nothing like concept sketch.

Feb. 1997

I hoped it would be ready by now, but you know how that is! Currently I am waiting for the output & power transformers I requested that all transformers be hand wound by one particular man, (one of the few older fellows still alive doing it) and am still waiting. I believe it will be worth the wait.

Last night (this is a classic example) a gentleman stopped by with his ADCOM amplifier to hear what it would sound like matched with a tube preamp. He had the most expensive and largest amplifier they make. It looked very nice. We listened to it for a half hour or so and he was impressed with the idea of a tube preamp. Between you and me, it sounded fair with the a few shortcomings of being a little dry and a little thin sounding unless it was really cranked. I don't remember how much power it is, 500 watts per side or something.

As we finished, he asked what that preamp on the floor was like. He was pointing to the SE-6BQ5a. I told him that was an amplifier, currently running pure class A triode with a 1.8 watt output per channel. I went on to explain the whole thing to him. Well of course he wanted to hear it so I hooked it up where his Adcom had just been. The bass was full & rich, and everything sounded better.

It was having no problems maintaining the 90 dB playback level we had been listening to and in his own words, besides saying he couldn't believe it 42 times, he said "At this playback level my Adcom's got NOTHING on this!" He was right.

I am very excited about this project! With the perfectly flat hand wound output transformers, silver wire, and 100% polypropylene power supply there are very few amplifiers that will sound as good. The only ones that would stand a chance are other single ended triode amps costing as much as a new car.

March 1997

While waiting for my transformers, I have had some time to re-analyze my thinking on all aspects of this design. The only thing that is certain is the circuit itself. Parts and layout are still open to review. Certainly for the purists and seasoned audiophiles I am on track with my 100% poly caps in the power supply and signal path. Make no compromise on parts quality, including wire and solder and lets see how good- good can get.

Perhaps if I'm going to make references to "Zen" in the design of this amp I should pay some attention to it. An interesting thing has happened this past month while waiting for the transformers. I was commissioned by a studio in New York to build a tube equalizer that would warm up the recordings. It would be the last thing in the signal path just before the master deck. They wanted that enchanting "tube sound" in their final product, the recordings.

I took on the project with the approach that I would give them some basic tone shaping in the bass and treble area nothing else. I figured if they need to EQ it more than that there is something wrong elsewhere in the signal path. This being the case, the front end of the SE6BQ5 circuit would work perfectly. So would the basic chassis. This would give me an opportunity to explore some variations of the project, and let me really analyze the sound of the front end as a separate pre amp. This also gives me an opportunity to try some different twists on the power supply.

Thinking about marketing and other non Zen thoughts I did a really stupid thing. I built the full blown power supply that goes in the Zen amp for this pre-amp project. I also made some changes to the solid state rectification using diodes and very large filter and B+ caps. Here is a picture of that power supply. A little overkill ha?

My thought was build a solid state rectified duplicate of the tube rectified power supply I would be using in the Zen amp and see which I liked better. The problem was that I had a B+ of 435 volts and only needed around 270v. Not wanting to introduce solid state regulation (the natural solution) I tried to wrestle it down and work with it. The result was a poor signal to noise ratio that was audible.

I solved this problem by coming back down to earth and just building the proper supply to do the job. I chose two 300ma transformers, one to run each channel. I ran a full wave bridge off each one through a one ohm resistor, followed by three sections of filter caps. This gave me what I needed to accomplish a true dual mono unit. Why not right? I did the same thing with the heaters, using one large 100,000uf 20v cap on each side. Now I had a dual mono supply with dual mono DC filament supply and no solid state regulation. This is an obvious improvement over the first circuit.

The next interesting development was the way I immediately dumped the very best poly caps I had (combinations of Multicap and Rel caps) for everything in the signal path. I let the unit burn in for a week and was surprised to hear it sounding as good and actually a little better in some ways than my pre amp. This is my own interpretation of the "Last Pass" for the popular Dynaco tube preamp.

The result was that the pre amp was "too good". In other words it was very very very fast, extremely revealing. On my high end system it sounds wonderful. Substitute a normal CD player, or mid-fi solid state power amp into the equation and the sound (for me anyway) was unlistenable. One of the secrets I know to be true in all musical sounding systems is balance. All pieces of electronic gear in the system must be of equal speed and quality regardless of the value.

Since I wanted to accomplish a "tube sound" in a solid state signal path of a recording studio, this wasn't going to work. I needed something that warms, soothes, which translates into subtle filtering. Something that wasn't so fast and so transparent. To do this I removed all the high end caps and installed normal mylar caps very similar in sound to original caps used in the 60's. I also changed the resistors back to 5% metal films. Part of me thought I was really crazy at this point.

With great anxiety I took the reworked unit back into the listening room and plugged it in. Get this... I was actually shocked when music came out, and then had to quickly remind myself that of course music came out. Just shows how brainwashed we get by listening to everybody else. I expected the sound to be so pathetic that it would justify my original implementation of the good caps. And it was... for the first excruciating 30 minutes... while the caps seated. But then guess what?

The stupid thing sounded warmer, richer, and the highs were nice and sparkly and most important, the sound stage was still there! Hmmm. Okay, we can fix that, bring in the Sony power amp... and that 200.00 CD player over there. Now we have a mid fi system on high end speakers, a cripple from the start. Well, that was the best I had ever heard that gear sound. Gee, it's working, this thing is making flat dry nasty stereo gear jump back into the 3D high end sound stage. The difference is rather amazing.

This means that the secret to a musical Zen amp for the masses is not going to be found in the high end caps. (A rather hard pill for me to swallow btw.) That means I am going to have to build it exactly like I just did this pre amp and that means I will have to make some "Silver Edition" units with the originally intended parts for those audiophiles who have the gear to back it. Consider the conceptual drawing I did of the chassis to be what the Silver or Special Edition model will look like if and or when I decide to sell some.

Meanwhile, staying focused on the original intent of this design I have elected to go with a more straight forward look. And because of the success I just had with the studio's pre amp, I am going to offer two products. The Zen amp as intended, and a pre-amp. This way those of you who have the larger amplifiers/less efficient speaker thing happening can benefit from the corrective qualities of this pre amp. In other words we can help more people create a musical sounding system. See how things work out?

August 1997

The iron samples have finally come in and I am very pleased with them. Now all that remains is to build the little guy and see how it compares to the prototype.

I've made all the decisions needed to build the first pre-production unit and have completed it. I kept the layout symmetrical so the amp looks good.

June 2001

Well, what a rush! This is the first time I've gone back to this page since August of 97. The Zen was optimized for Triode use only after the first 25 units were sold. Shortly there after the tubes were upgraded to SV83's and 6N1P's and it has remained basically unchanged since then. We have hand built over 600 of these amplifiers. In fact we have developed an entire line of Zen Triode Products along the way. Many Thanks to everyone who is supporting us by enjoying these magic little amps!

January of 2008

Serial #1000 of the little gray amplifier (Model SE84C) was built and shipped. The chassis was retired but the amplifier lives on in a slightly larger and significantly heavier black steel chassis with a front mounted gain control and 2 sets of inputs. The new model is called the SE84C+. A history detailing the revisions can be found in the articles section of the web site. At the time this article was written I never dreamed we would have hand built and shipped a thousand of these, not to mention a few thousand more amps that we designed based on this concept. Just goes to show I was on the right track, and it remains our top selling amplifier today.

paper003

A SINGLE ENDED TUBE AMP FOR THE MASSES

Part III - The Chassis

To TWEAK: Taking something and altering portions of it to effect better performance. ...also a disease afflicting some audiophiles unable to stop tweaking: audiosystematatweakitis.

A loudspeaker is a necessary evil that is required to convert sine waves into sound waves. It is in most cases a balance of compromise. Many people do not realize that a loudspeaker cabinet is responsible for around 70% of the sound quality and performance. The actual woofers and tweeters are less important than the cabinet if choices must be made. Below are some things you can do vastly improve a speakers fidelity.

SPECIFIC TWEAKS

Installing strategically located bracing to reduce cabinet resonance makes such a tremendous improvement in the solidness and focus of your sound that you would be amazed.

Measuring the woofer's specs and tuning the cabinet exactly to that woofer will get you maximum performance with the flattest response. Most are found to be more than 20% in error!

Carefully reinstall a port that is aerodynamic with flared or rolled edges will remove coloration, wind noise and improve power handling.

Installing adjustable spikes on the base of the cabinet will reduce or eliminate cabinet rocking which happens on a microscopic level will greatly enhance the focus of high frequencies and the solidity of the bass.

Installing sound absorbing materials such as cork, or felt on the baffle will reduce rarefaction making it difficult to localize your speakers. This enhances sound stage topology in the stereoscopic array. Makes you speakers have a chance at disappearing when the music is on.

Reinstalling drivers to be exactly flush with the baffle will improve the flatness of the frequency response of each driver.

Reinstalling high frequency drivers with composite isolation (poured flexible sealant) tremendously improves the bond between driver and cabinet while at the same time dissipates cabinet resonance into heat so that they do not smear or color the sound from those drivers.

Reconfiguring the array when necessary and possible to a line source array will usually improve imaging and depth enough to justify the new baffle.

Installing the tweeter on the top of the cabinet at the proper angle will physically time align the array, completely flatten its response, require less crossover components as a result. Makes your sound stage presentation acquire dramatic depth.

The worst sound you've ever heard in your life comes from hard metallic chamber created by the magnetic pole piece and voice coil assembly and dust cap. 90% of all drivers I've inspected (1000's) are built with the voice coil former protruding past the cone by as much as a half inch or more. This thin aluminum cylinder rings like any pipe does when vibration is introduced into it. Eliminating this excess and dampening the harsh metal pole piece with a domed felt plug removes perhaps the most major downfall of cone speakers - that cone speaker sound referred to by electrostatic speaker owners.

Dampening the dust cap or installing a soft butyl rubber dust cap or eliminating it by installing a plug helps hide the remaining nasty sound described above.

Securely re-gluing the voice coil to the cone can evenly dissipate nasty resonance's from the voice coil into the cone where they can become lost. It also improves the balance and precision of energy transfer through the assembly. About 50% of the drivers that come through our shop were not glued with this precision.

On woofers - welding the pole piece to the basket rather than the centrally located spot welds, will stop the magnet/pole rocking that happens at high output levels.

One of the most common tweaks for all drivers (other than tweeters) is the application of anti-resonance pads on the basket. Most speaker baskets ring like a bell when struck, so when music excites the frequency of the basket, the sound suddenly becomes harsh. Visco-elastic damping laminate, the technical name, is what I use to solve this problem.

paper005

TWEAKS FOR YOUR SPEAKERS

by Steve Deckert
Nov. 1997

Living in the smack middle of the USA surrounded by corn in a society where audio is whatever they tell you it is, and high end audio is an incomprehensible psychedelic concept too ridiculous to be taken seriously... an audiophile could feel a little lost. Around here, high end shops sell mid fi - that to the encompassing miss informed local mass, appears to be hi fi.

I guess keeping this in perspective, I would think that possibly say what... 95% of this entire country fall into the same category of perceived audio nirvana phobia, where an appreciation for the emotional / spiritual intercourse with music does not exist.

I would argue that this is not the fault of the individual, but the fault of our society, somewhat aggravated by marketing. I can support this with the observation that the majority of "common" people who I've exposed to the experience of musical euphoria left with a clear understanding.

I don't think it's popular in this society to spend money and time creating a spiritual transducer that really works. If it did really work, it would probably be ugly or at least considered on the fringe of abnormal. I wonder why it is when a man dedicates a room of his home to become his sanctuary and spends thousands of dollars on gear to make it all happen, he is considered so odd.. Foolish even perhaps? I don't know about you, but I can answer that question in 500 pages or less.

Don't worry, these primarily men are basically harmless. In fact we have categorized this strange behavior with a special word that the effected parties are tricked into telling everyone who will listen.. That they are in fact an (the word is) "audiophile".

In this intensely market driven country, it seems the audiophile community has been contaminated with performance. I would like to know exactly when and who it was that decided performance was the criteria for judging audio. We should all go to Japan and wake up. Everyone in Japan knows that the superior cone material for GOOD SOUND is paper pulp. In Japan, it is common to find the arguments over magnet materials and the best sounding pulp fibers being some of the dominate issues.

Over here we're so concerned about about being serviced by everything that we lack the ability to comprehend what it is like to commune with our high end gear. Part of the reason for this is the simple fact that most of the stuff I've listened to in this country sounds bad enough to stand little chance if none to invoke any sort of spiritual response from the listener. Trust me, high technology and injection molded graphite and kevlar cones are not going to do it.

In fact lets think about it for a minute... small speakers, convenient little boxes, big amplifiers, high tech cones and speakers to handle the added stress of a culture that thinks driving a boat 70 mph around the lake is easier than crossing the bridge to the other side.

Let suppose you have a small box speaker 87 dB at 1 watt, probably the standard in this country. You want one that will handle as much power as possible so you can play it as loud as possible with God forbid, no distortion. This leads to overly complex multiple driver arrays, subwoofers and has set the stage for a marketing feeding frenzy that most audiophiles have fell for hook line and sinker. Wouldn't it have been just a lot simpler to listen to a larger speaker that was efficient so that just a few watts was too loud? Wouldn't it be a lot better for your amplifier to driver something that didn't make it see red all the time? Only large speakers can deliver this. You see, in real life, sound waves cannot be scaled to fit your life. Low bass waves are 80 feet apart and expand like waves in a pond when a pebble is dropped. To reproduce life like sound, you need a large speaker, preferably with only one driver in it.

To accomplish this means commitment and desire. The desire to make communion with music a priority in your life, to involve your mate and friends in it and then the commitment to do it. Since in this culture we, men, typically don't involve our mates in our audio quest for truth, it's no wonder they won't tolerate large speakers in their face. Oh I know, we've tried, but they're just not interested, or impressed. What you don't realize is that they, uncontaminated by the hundreds of hours reading about audio, can still hear objectively. What they hear is a usually dry, grainy,overly bright two dimensional sound that makes it impossible for them to take you seriously.

Go to Japan, or some of the enlightened ones in this country and have a listen to single ended triode amplifiers on masterfully built sexy looking horn speakers and you will see where I'm coming from. Don't be surprised if the softest rug in the house is on the floor in front of those speakers because the kind of listening done there often involves a mate and often leads to much more than just listening.

It would be so nice in this country to see audio lifted from the materialistic wannabe plague that it is, to an experience that promotes a more spiritual mind set . If only people could realize how to do it, or more importantly why to do it. We'd have to watch less TV. We'd have to spend more money on our stereo instead of things that pollute the earth.

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ARE WE ALL CRAZY?

by Steve Deckert
Oct. 1997

Our popular little Zen Triode amp model SE84B has been revised again! There is some history on this located in the specifications page for the Zen amp, but I thought it would be a good time to do an overview on the history of this little bugger, now that it has one!

A good place to start would be the original design log, written during the first year of development. It will give you some insight into the birth of the idea and some of the ways I thought I might implement it.

This paper will simply document the history of revisions and some of the things I've learned after hand building around 500 of these amps.

The original SE84 was an EL84/6BQ5 based amplifier using a 12AT7 as the signal tube. It was configured as BOTH a single ended triode OR a single ended pentode amplifier based on the position of a switch on the front. In Triode it was around 1.8 watts per channel and in pentode it was around 5.7 watts.

There were 50 or so of these models built and close customer feedback was maintained with almost all 50. We learned that customers preferred the sound of the Triode of Pentode in all but one case. That meant a switch designed to offer two different sounds wasn't being used. It also meant that an amplifier designed to be both pentode or triode was not fully optimized for either.

Then the revision A came out where we made some serious changes. First the output tubes shipped with the amps were now SVETLANA SV83's which are a high performance version of the original 6BQ5's. The power supply and circuit were redesigned to favor triode operation and at the same time the option of running the amp in pentode was removed. The switch on the front was then converted to a bias switch offering the customer two different signatures buy changing the bias of the signal tube. The signal tube was also replaced with a high performance version of the popular 6DJ8 by Svetlana called a 6N1P.

These revisions made a large improvement in the sound of the amplifier, and at the same time we started building our own chassis with a durable finish of the highest quality. I personally hand built and drilled the chassis for the first 50 amps and if I never drill another hole in this lifetime it would be just fine with me. Even though the quality of the product went up with the fidelity, we kept it at the same $499. price because sales were just starting to get serious.

Approx.. a year later, and after another year of experimenting, we modified the power supply again launching the sound of this amplifier into the big leagues. This was the beginning of our understand about speed issues within a circuit. Many people don't realize that it is actually the way you design and build the power supply that accounts for the fidelity of an amplifier. In fact it makes a much larger effect than the circuit itself. This modification took the amplifier into it's revision B and has solidly been getting rave reviews ever since.

Now, after two more years of tweaking, and with knowledge gathered from developing our other products, We have redesigned the power supply one last time and resolved what is our current understand of speed in a way that improved the musicality of the already wonderful amplifier by a very noticeable margin. This new power supply also includes our own power transformers made here in the USA to spec just for our Zen amp. These power transformers are superior in quality and consistency to the Hammond power transformers we've used up until this point. The Eureka that caused this most recent revision was so good that it musically outperformed the supply in our Signature monoblocks at 5 times the cost. Fortunately this happened two weeks prior to the start of production of the new mono amplifiers, so the new power supply that is in the revision C is also found in part on the new signature mono blocks.

It's one thing to experiment until your old and gray with documented modifications to amplifier projects but nothing like doing that obsessively and gathering feedback from 500 happy customers in 500 different systems/rooms. The priceless knowledge from that process is the sole reason why we don't sell through dealers. I personally talk to almost every customer in depth about likes/dislikes and wouldn't have it any other way.

I often have flashbacks to that first few amps, and the literally 1000's of hours of tweaking they got, and how I thought I was done and nothing could be improved. Then I come back to earth and look at where the product is at now and the gap between the two is huge. Unlike I would have ever imagined, I have realized that a truly great amplifier is the result of both the original design and the process and experience of building 500 more. That is probably the most interesting thing that has come out of this for me personally. Truly great amplifiers evolve. This means that if I wanted to design and build an amp from scratch for myself, like many of us solder-slinger's enjoy doing, no matter how long I labor over it to get it right the amp will ultimately not be as good as it would be if I put it in production and let it evolve over a few years in hundreds of different systems. This goes against my original motivation for building amps - which was that you can usually hand build an amp that sounds better than production amps you buy at the store. Both sides of this paradox are true. The catch is the circuit boards. Most production amps use them, we don't.

To date, the things I've learned since the first Zen amp prototypes are so numerous I can't begin to explain them here. But I will say that the common denominator is the opposite of common understanding. The biggest obstacle in staying true to this intimate design process is deprogramming yourself. In audio, it would be far more likely that you would accidentally come up with something great if you had no idea what you were doing. I've noticed that everyone seems to copy everyone else, and most rely on the test gear and calculators too much. Around here the ears have it, regardless of what the scope says. In fact we never measure anything until we're completely done with it. Once you get honed in on something during the voicing of an amplifier, paper can be very distracting. In the end, if it sounds good, you'll find that it usually measures pretty darn good as well.

I don't anticipate any more revisions to the Zen amp, but I said that after the B revision too. Sometimes the art in the science is knowing when to quit. Our attention now is on our signature monoblocks, and our tube line amp and preamps. These line level products will make it possible for those who already have high power solid state systems to taste some Zen.

To ensure it's place in history, we are manufacturing SELECT versions of the Zen Triode that use the same parts as our Signature Gear, and clearly push the envelope of fidelity.

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FROM A to C, THE ZEN TRIODE HISTORY

by Steve Deckert
Oct. 1997

It was the wee hours of the morning as I can recall, a hectic day had passed, and I was ready for bed. Everything was quiet, the air was still and a sense of peace encompassed the place. The magic hour was almost upon me, but as usual it meant I got to go to sleep and that was magical enough. Nevertheless it is that hour the begins to open a window that lasts usually until 3:00 am when listening takes on a new dimension.

I walked through doing the bedtime check, part of which is going to the front listening room and getting the blasted cat, Tesla, out of the subwoofer. It seems that the sub has become his new throne. He gets pissed when I try to extract him from it. We had our little confrontation, and Tesla grumbled off into the darkness in search of the next best thing... his food bowl.

On the sub was number # 22 of my SE84 little Zen amps that I had left on from a demo earlier that evening. The little guy waiting for some Sylvania NOS tubes to come in on Monday so it can ship out. I reached over to turn it off and suckered into the same old trick of seeing how long I could hold my hand on the power transformer before my finger nails start smoking, which by the way wasn't very long tonight.

Oh what the hell, I haven't looked at the time, but we're probably right in the middle of the magic listening window, and this thing sounded like it had its first bloom earlier this evening... leave it on... let it cook out another tune, I want to hear my stereo real fast before I retire for the night.

I put in an Aaron Neville CD, a recent gift from someone who appreciated the demo yesterday. I had already listened to it perhaps 6 or 7 times, enough to be familiar with it and I wanted to hear it again!

It took only the first few bars and I went into stage one - the open mouth I can't believe it look... oh yes, It was alive tonight! I was as usual only planning to listen for a few minutes if that and shut it down, but this rearranged my priorities without effort or delay.

I sat and listened to the next song and while silently losing track of where my body stops and the chair begins, and marveling at the incredible articulation, the nice wet blooming midrange and the fact that the bass was coming from inside my body and going out into the room. The progression into stage two - focused listening, where the stress of trying to hear something wrong has been replaced by complete surrender as you tease euphoria.

A few more songs had passed and the release of denial that it can't be sounding this good gives way to stage four - foreplay. This is when your body has become one with the chair and your spirit begins to flirt with the space around you. You slowly focus your senses to a heightened state where you have the hearing of a blind man and your body becomes and extension of your ears. Oh the depth at which you can hear. This is when you can start to trip on conversations in the control booth behind glass at around 60 dB down. It is when focus becomes so great that you can hear a pencil hit the floor 150 feet back, and roll in a pie shape arc along the floor. You can hear it has flat sides.

A half hour has passed and now time does not exist. The foreplay has triggered stage five - euphoria. This is when your emotional and physical senses become so acute that they overlap causing your mind to forget which sense organ is doing what. Your sense of smell becomes hearing, your hearing becomes site and you leave your physical body and become the music.

Then after you've pushed repeat 3 or 4 times your heightened state collapses and you come back. In a state of humble shock, you reverently touch the magic tube amp wondering what alien force just possessed it, and then turn it off. Safe now, and back in control you dash out of the room with the energy of a 10 year old saying holy shit at least 400 times and then collapse in your bed.

Does your stereo do this to you? Don't you wish it did?

This experience I'll admit is rather new to me, a direct result of our Casprera System, but the middle of the night blooms are something I've puzzled over for many many years. I used to get so irritated that the stereo would never sound like that in the day that I put more than enough effort in trying to discover why it is.

Although the Room Treatment is what took me to stage 5, my other work over the years would frequently take me to stage 4 but only between the hours of 1:45 AM and 3:15 AM give or take an hour for daylight savings time. During the day stage 3 was all that you could ever hope for.

Naturally I have confirmed this with enough audiophiles in different parts of the country to know it is not just a unique experience I'm having but stereos actually DO sound better in this night time window.

It all started several years ago at my first location, where I would be up late working on the computer with my stereo playing in the next room. I typically will have been sitting there working for several hours and the stereo playing unattended the entire time. Then IT WOULD HAPPEN. Suddenly the sound in the other room blooms and becomes distracting because of the profound change. Just that fast you sit there starring into the monitor with your complete undivided attention on the music coming through the doorway in the next room. You get up and walk in there because you can't believe what it's doing. Suddenly ALL grain is GONE, the sound stage goes from 12 feet to 30 feet deep, and everything becomes holographic.

3D sound, so convincing it tugs on your reasoning and spawns an uncomfortable feeling as your mind starts to short out. The eyes and the ears disagree, ...Which will win? Time and time and time again this has happened. It happens out in the shop on the old console stereo from the 60's, it happens at my bench on the crappie car stereo/monitors I have back there...

About 18 years ago I did some work with our local electric company that allowed me to go inside the nuclear bomb proof underground control center that manages the power distribution for our city and surrounding area. It looked like a scene straight from Star trek. Curved walls with floor to ceiling schematics of the entire state, LEDs blinking all over the place. I sat at the captions chair with the arc shaped control desk in front of me and saw a giant knob marked "cycles". There across the room was what looked like a large clock, no speedometer because it went from zero to 100. There was a large analogue hand melodically hanging at 57 cycles. Hmm, I thought, is that what I think it is? I asked the operator still waiting for me to get out of his seat, and he confirmed that that was in fact what controlled the frequency of ALL the AC generators in the three connecting plants around the state.

My first reaction was hey.. You can't do that! Well, it turns out that during high heat days in the summer it cost less money to manufacture the energy at lower frequencies. Then at night around 1 or 2 o'clock, he turns that big knob and the big gauge across the room crawls up to 62 sometime even 65 cycles so that they can speed up everyone's clocks to catch up for the lost time.

I thought I had found the answer to the magic hours but since then I have been using a power conditioner (a real one) and it maintains noise free 60 cycle 120 volts AC regardless of the input. And while that improved the sound during the day, well all the time really, the mystery middle of the night blooms continued.

I have since then found that it seems to be many things that align themselves on a coherent harmonic that yields the effect.

Although an unregulated power supply on a basic tube amp will perform better when you bump up the 60 cycle AC a bit, it turns out that it is the harmonics in the power lines surrounding your area that seem to be responsible. During the day with hundreds of things running off of ultimately the same power source, the AC power in your lines is full of contaminants that add grain to your sound, and collapse your sound stage.

I believe it is the reduced level of power line harmonics that make possible the middle of the night magic, triggered by the increase in Cycles on the AC power, combined with the fact that this is the time when the Sun is on the exact other side of the planet. Radiation from the sun adds it's own effect to power line harmonics in my observations. And finally, the reduced ambient noise floor you typically have at those hours of the night let you hear more dynamic range.

This is my theory, and as person who likes to invent audio products, I'm still frustrated that I don't have a concrete answer. If I knew exactly what it was, perhaps I could bottle some up and sprinkle it around the room during the day!

If you ever want to experience the 5 stages I talked about in the start of this rambling, just come over (call ahead please) and be prepared to wait until after 2:00 am to start the session.

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THE MAGIC HOUR

by Steve Deckert
Nov. 1997

Sometimes I have to wonder if aliens (out there) aren’t entertaining themselves at my expense! I don’t mean with occasional incidents but rather with an on going theme. Perhaps a better word for it would be “lesson”.

I almost wish audio was in a world where there were no such things as labels, name brands or trade rags. From an audio perspective these things have just gotten in the way and caused me years and years and years of delay in reaching the holy grail of audio playback systems.

Perhaps in “their” world, this is the case. Perhaps that theme of paradoxical events that happen around here (almost monthly for reasons I can’t figure out) are why I have found the grail where so many others haven’t yet. Nevertheless it never ceases to amaze me.

Tonight has been no exception, as the little prankster’s (aliens) have been at it again. Their favorite joke is to make the underdog ALWAYS sound better and then watch you try to figure out why that is. This is in fact the running theme behind most Zen designs around here, and is what distinguishes them from a regular one (I do both kinds).

Let me explain what got me befuddled again with an excellent example by just telling you how the evening went. Oh I’m SURE this has never happened to you... (smile) but then come to think of it maybe it never has! You know since audio playback systems require components, there is a certain amount of material acquisition required. That ongoing measurement of ones possessions as referenced against another’s with money being the mark of distinction.

That system of distinction is a dangerous path where audio grail hunting is concerned. It seems to offer short cuts to the land of OZ but actually stops just before you get there. Of course I’m talking about audio gear and the assumed safe statement that if something costs 10 times as much it will sound at least twice as good!

I have been going round and round lately with tubes for my new Zen amp. Which tubes are the best sounding? It started out a simple enough problem, just buy a few of all the popular brands and see right? Pleeease...!

Why can’t anything ever be simple? My range of available tubes discounting the Chinese ones, started at the low end with Sovteks and ended with the best being NOS Sylvania Military grade. The difference in price being around 500%. In the middle of my selection is a wide variety of British and American tubes.

For marketing reasons I wanted to at least try the Sovteks and see how they compared, so I bought their best grade of select tube and gave it a go. I listened to it for a couple days and one night when I installed a 30 year old pair of British Made pull-outs with low mileage all the grain went away! ...That’s about right.

Towards the end of this tube discovery process, I ended up getting my hands on a pair of N.O.S. SYLVANIA milspec tubes. They even looked serious! The plates are almost black and the bulbs are seamless. They became my little pets for about a week. Indeed they sounded good until I was able to admit to myself they really kinda sounded bad!

Needing even MORE tubes, I ordered some more Sovteks, but this time their bottom of the line 6BQ5, not the M’s not the Select Grade, just the 3.50 ea. in matched sets. Well just for kicks when they came in I popped them in my Zen amp in place of my little pets, and I’ll be damn if they didn’t sound better! .... about right... he shakes his head.

After comparing the three types of Sovtek 6BQ5’s I have to say the worst ones sound the best and the best ones sound the worse. The cheap one is grainless and quiet. The M and Select are more aggressive on top with more grain.. at least in the amps I've tried them in. Warning this text is seeded with a subtle moral.

Tonight, I thought I would listen to our Golden Tube SE40 (first model) 40x40 single ended pentode since I pretty much abandoned it after completion of the Zen amp project. After about 10 minutes I remembered all the reasons I abandoned it, and reminisced about how good it used to sound, and how well it compared with high dollar amps. To read reviews on it alone is a paradox about underdogs wining the fidelity wars.

The sound of the SE40 didn't change, it sounds just the same as always, but now after listening to this inferior looking Zen amp 2x2 watts single ended triode my reference has changed. The Golden Tube SE40 now seems cold, thin, grainy, unfocussed, and this is what really surprises me,.. slow! It shouldn’t be possible for a 5 watt 500 dollar amp to walk all over an 80 watt 1000 dollar amp that walks all over several popular 2500 dollar amps, but it does. That’s Zen.

After hitting pause, and returning the Golden Tube to its shelf I got a Zen amp out and prepared to listen to it. I grabbed what I was still thinking was my favorite tubes, the Sylvanias, my pets, and popped them in. While I was down there I discovered something that should be impossible. The tubes were microphonic! I could tap them with my finger nail, and hear the corresponding speaker ring like a crystal wine glass!

Can you see the head trip? Prior to this little chuckle, the aliens made my stock DENON 2560 that I was using as a transport sound better than the DA converter, and last week made a tweaked pair of audax 40 watt paper cone speakers sound WAY better than a tweaked pair of Dynaudio’s best woofers.

I won’t even get into the studio downstairs, my drum kit, or our band equipment in general, but I can assure you the phenomenon is alive and well down there too.

And if there really aren’t aliens watching me, I can safely say I have been providing an almost daily source of good free entertainment at my expense for their mental enlightenment and it's a shame their missing it.

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AUDIO PARADOXES

by Steve Deckert
Nov. 1997

The music of the Nutcracker Ballet was composed by Perer Ilyich Tchaikovsky. Born in the Ural mountains of Russia, he dedicated his life to music.

1850 to 1859, he attended the school of Jurisprudence and studied piano. In 1861, he attended classes with the Russian Music Society. In 1862, he entered the Saint Petersburg Conservatory.

Beginning in 1866,Tchaikovsky taught at the Moscow Conservatory while composing many of his concertos and symphonies.

In 1892, Tchaikovsky composed the Nutcracker. Last night on 11/27/97 this man rolled over in his grave thanks in part to a presentation of the Nutcracker here in the Peoria Civic Center Auditorium.

Yes, folks, he rolled over in his grave on this occasion when he found himself being paged by the stringent mental beacon I sent out during my 3 hours of suffering last night while I attended the ballet in order to watch my daughter perform.

Eight musical pieces that support this ballet were brutally assassinated while trying to be reproduced through .... I'm sorry, I'm just without words for it.... I guess I was the P.A. system?! See Figure 4.

One of the problems with small towns (cities) like Peoria IL. where I live, is the absence of real culture. Years ago an attempt to bolster downtown development materialized into a project called the Civic Center. In this massive building there is a full size arena, a theater, and lots of general meeting spaces. The idea was to attract concerts, ice shows, truck pulls, and cultural things like that (as they put it) to bring more money into the economy.

I've always looked at Peoria as a wanna be city with delayed mentality. Tonight was a perfect example of what I mean. I checked out the theater when the thing first opened hoping for something special and didn't find it so it has been probably 10 years since then before I returned last night to watch my daughter's performance.

Being more attuned to acoustics since my last visit, I was looking forward to watching my daughter and dreading everything else I would have to suffer through (like the rest of the performance).

I walked into the auditorium and found my seat in row L. I was number 39. It was hot, and the place was packed. It seems that no one there understands that when you fill a room with 500 people in the course of 30 minutes that the BTU increase generated will make it impossible for a quick temperature recovery so everyone baked.

Frankly I would love to experience the Nutcracker, but I don't see it every happening around here. To me experiencing such a performance includes marveling at the acoustically inert architecture and the ornate attention to detail that shows we care - is as much a part of it as the real orchestra. After all it is the dynamics between the room, performers, and audience that makes it a production. When I sat down and looked around the auditorium I was coldly reminded at how much we really don't either care or don't really get it.

The architecture was full of right angles and flat surfaces. It was more contemporary styling... a side effect of building construction when steel studs and drywall are used. It had employed some acoustic considerations, those that you might expect to see come out of our local sound contractor/engineering pool. Public address specialists with no clue what good sound is.

They framed the stage with a rectangular expanding louver that was built with plywood, 2X10's and 4" PVC pipe cut in half lengthwise and glued on in a fan shaped pattern for decoration. Then the entire abortion was spray painted gold! ...Now isn't that special. Needless to say this was no opera house. I didn't see any musicians, no pits, no hope. Then I looked up and saw this welded angle iron frame with 4 of the ugliest speakers I ever saw strapped on it. These too were spray painted gold!

I knew I was in trouble now. I was getting warmer and stuffier by the minute, and I had to break out a breath mint so I wouldn't keep smelling everyone else's bad breath.

I can't stress enough how important architecture is to civic functions. Every time I walk into a place like this, or a recently built church, or even just looking at the new construction, a part of me dies. I find it so sad, even though economic changes are to blame it is a sign of our instant lifestyles that I frankly am embarrassed to be associated with.

Suddenly the lights dimmed and this 3 hour ordeal is about to begin. Of course while everyone else was waiting to WATCH the show, I was cringing with anticipation. As I lookup up at this monaural gold plated birds nest waiting to hear if they were actually going to use it... the damn thing came on! There were some road gear type speakers on either side of the stage pointing directly at the foreheads of those seated there and I thought those would be used. No such luck.

Five minutes into the production I had to overcome a strong urge to escape. In my mind I screamed "what is wrong with you people?" Let me describe the sound for you...

Picture your grade school gym with a school play being sound tracked by a cassette deck playing into a microphone through steel P.A. horns. See Figure 4. Picture the sound of sandpaper going through a meat grinder with a lisp.

Beside the fact that several of the cones were ripped and fluttering, the SPL was down so low (actually thank God for that) that the sound of the dancers socked feet hitting the hollow stage was louder, making the free floating ballerinas come off as fat thumping amateurs.

The crescendos compressed down to a signal to noise ratio of around 3 dB and literally made me jump around in my seat. I wanted to turn to the women sitting next to me and exclaim how pathetic this is, but I didn't.

Over the next 3 hours I had one fantasy after another. They alternated. The first one was about finding the people responsible for this sound system and scold them to tears. The next one was about how I would design and integrate speakers to project a sound field that surrounded the performers. Those poor dancers couldn't feel the music, and I'm certain that they barely could hear it. My next one was how the dancers, audience, and anyone who wants to join in could find and mob the people responsible for this sound system.

I have to say that it was the longest three hours of my life. When the glorious moment arrived - the end- my pounding head had fatigued to the point I just wanted to go home instead of take any kind of action.

The room cleared out a bit now that it was over, everyone had the warm glow of just seeing a show. This amazed me more than anything else. The audience as a whole seemed to enjoy it. Reminded me of a bunch a cattle. Why could they possibly think it was great? I can only conclude that because it sounded like their disposable solid state "digital ready" stereos at home they found no fault in the presentation.

Am I being over critical, this audio guru who was just sonically assaulted says no. No I'm not. If our culture in these smaller communities understood the true intent of Tchaikovsky's work and understood that fidelity is the hallmark of that man's work, the people who designed this theater and sound system would have been laughed out of town.

None that saw the production last night or who will see it tonight will have had even remotely close to the intended experience.

While waiting backstage to see my daughter I saw this little man walk by with a CD. I followed him to a table where some maintenance man sat with a 3 channel mixer and a Sony Walkman CD player. Boy here was my chance. I could execute fantasy # 17 that occurred during the end of the first scene of the second half...climbing up to the speakers and cutting the wires. I was going to put one of those mattress tags on the back of each speaker that reads: Inserting speaker wires in these speakers is punishable by law.

Well, as I looked at what was before me, I knew it was hopeless so I kept my mouth shut, found and kissed my daughter and went home.

I had a similar experience to this in a new church where some sound contractor over killed a mono birds nest with a 64 channel mixer and 8 Crown Marco Techs. Everyone in the church will tell you they have the best sound system because it cost $80,000. I could have, in that particular room, used a pair wooden horns and a 12 watt tube amp and had better sound that was plenty loud enough.

I guess if you were a doctor it would be like going into a hospital where all the surgeons just used their fingers, and everyone died, but they thought they were doing a good job!

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THE NUTCRACKER

by Steve Deckert
Nov. 1997

I have to admit that since meeting Dan last year and helping him in the development of his room treatment products, I have been giving more thought than normal to room acoustics. And one of the most interesting and on going arguments I've seen in the audiophile community is the one about direct vs. reflected energy. Bose gets a bad rap by many audiophiles because they are always reflecting some energy off the walls etc.

There are panel speakers that radiate in a dipole pattern,
open baffle speakers, conventional "audiophile" direct radiating speakers, spherically enclosed moving coil speakers, 4 sided pyramid shaped speakers with moving coil speakers on all sides, and radial speakers that use typically a bending wave cone, or bladder to radiate sound in a 360 degree pattern.

Here is what I have found...

Lets eliminate electronics from the equation and just focus on the relationship between speakers and your room. It has been my experience that in the categories of imaging, soundstage size & depth, focus, and believability, the relationship between your room and speakers is actually more of a factor than what type of speakers you have.

If we look at the most common type of loudspeaker, that being a cabinet with the drivers in an array 90 degrees from the floor and at a parallel angle with the walls as our sample. I will try to paint a picture of what happens.

First of all let's reduce our example to a single woofer that plays out to between 1000 and 2000 cycles. Regardless of the size (diameter) of the woofer, it will radiate the majority of it’s sound in a beam pattern of 30 degrees or less.

Let's say the speaker is 90 dB efficient and in a 14 x 16 listening room. (The exact size of the room is not a critical component in this illustration). Lets only look at one speaker and assume it is set up in the conventional place out away from the walls and pointing at the listening chair centered in the room.

This is considered a direct energy listening scenario. However you will only hear direct energy in it’s virgin state come from the speaker for the first 10 to 30 milliseconds... after that the bounce off The rear, side and finally front wall will blend across your sound field creating a smearing effect. In this sense there is no such thing really as direct energy unless perhaps you hung your speakers and listening chair from a crane several hundred feet in the air out in the middle of a corn field.

Because these three primary reflections are what destroy the focus of your sound stage, it seems to have been assumed that reflections are categorically bad. Diffusers offer some real advancements in controlling these reflections and if integrated with diaphragmatic bass traps can also absorb excess energy to minimize this evil. This is done by placing quadratic theory diffusers at all the critical reflection points.

Imagine the beam of sound coming from your speakers at a sound pressure of 100 dB. It has a cone shaped pattern of ever expanding wavefronts at around 30 degrees. It rushes past your ear and hits the back wall in a circular pattern of around 8 to 10 feet in diameter. The pattern of sound when it went past your head was about 3 to 4 feet in diameter. Since The sound at your ear was 100 dB at a concentrated diameter of 3 to 4 feet, the reflection off the back wall will be reduced by 50% power at a diameter of 8 to 10 feet. This means that reflection that is now aiming for your side and front walls and is at an energy level of 93dB! Naturally you will hear this reflection as it finally passes your head and it will be confused by your brain with the direct energy from the speaker making it hard to focus or localize the instruments in the recording.

By using quadratic diffusers we are able to bust these reflections down and change their pattern of radiation from a single specific angle to a 180 degree horizontal fan. By changing the energy from 30 degrees at the first reflection point to 180 degrees, you can see where the amplitude of that reflected energy would be substantially reduced by as much as 6 times, or 15 dB! At this amplitude your brain hears the reflections as ambiance and does not try to interpret them as part of the primary wave front. Result: Focused perception of a clear image.

Since this situation has been modeled and the result is my current listening room, I have come to the conclusion that listening to conventional speakers in a room without this quadratic theory diffusion is to listen in vain. No matter HOW MUCH you spend on gear and speakers you will not achieve the clarity and holographic presentation possible in your playback of the recording.

Speakers that have drivers pointing out to the sides or rear often accentuate this problem by reflecting concentrated patterns of energy directly off the nearby walls.

In the illustration of a single speaker in a room playing around 1000 cycles there are three problem reflection points that have to be dealt with to get good sound. As you can see it is an aggressive and unnatural pattern.

Let's look at natural wave fronts for a minute and compare them to the wave fronts that come off a cone shaped speaker... This is a shot of my listening room. Yes I know what live music sounds like in there as you can see. Look at the angles of the drum heads and guitar strings in relation to the room. The white lines you see are sound wave fronts that I tried to draw in. If you really observe this for awhile you will see that almost no musical instrument radiates sound in a cone shaped pattern directly at your forehead. The horn instruments with the exception of a few always point somewhere other than directly at your face unless that is the intended emphasis of the musician for a brief moment. This would tend to indicate that a conventional speaker can never totally get it right!

Recently, I stumbled on to a new d.i.y. idea that I am posting on the website called The "Radial Loudspeaker". As a result I have started to realize that this may be a design of loudspeaker that actually works WITH a room rather than against it as we've clearly demonstrated in the above discussion about typical loudspeakers. In this model we have a true 360 wavefront almost like that coming off the drum kit.

In the radial design, energy is even across a 360 degree plane and 180 degree hemisphere. If substituted for the conventional speaker in our earlier illustrations, you can calculate the following...

The wave front passes your head but this time it is already a diameter exceeding your room size. The reflection point is changed from a 30 degree 8 to 10 foot diameter standing reflection, to 180 degree graduated non-standing reflection, and hence 15 dB down at the first reflection point. Also interesting to note is that the room corner behind your speakers now becomes the first primary reflection, but since it is graduated it folds to become time coherent with the primary wave front as shown in blue.

In a test, one of these speakers was placed in a room and compared with a conventional speaker on the other channel. The fear was that because your ear only gets 30 degrees or so of the primary wave front, the energy of the speaker would have to be increased by a considerable factor to match the loudness level of the direct radiating speaker on the other channel.

Conceivably, this possible side effect could mean 30 / 180 or 6 times The energy to match our conventional speaker. That would be 15 dB, and that would raise the reflected energy in the room by 15 dB making the advantage we thought we had disappear.

What happened was rewarding. Since the room corner, i.e.. side and rear wall near the speaker fold the wave fronts into coherently timed graduated fronts, the listening chair actually gets the full energy of the 360 degrees divided by losses and graduated reflection is something like 360 / 1.4 = 257 degrees for a loss of 103 degrees or 28 % which equals just over 1.5 dB.

This was confirmed by listening as the conventional speaker had an efficiency of 90.5 and the radial had an efficiency of 95.5. When measured in the room against the 90.5 speaker, the difference was not 5 dB but 3.5 dB! This confirmed the equation and eliminated the fear of losing 15 dB. The only way that could happen is in a very large room or hanging from a string over a corn field.

Over The past few days I've been listening to this radial speaker in its unfinished state, and with all the room treatment removed I have as good or better (actually better) performance than using the conventional speakers with a full armament of room treatment.

paper011

DIRECT vs. REFLECTED ENERGY

by Steve Deckert
Dec. 1997

We have taken a small room with all the inherent problems (12 dB peek at 221 Hz being the worst) and given it the performance of much larger room. How do you make a tiny 13 x 15 room larger? The Zen technique would indicate that you make the room smaller and believe it or not we actually did just that!

The "listening room" before enlightenment... There was a reason for this at the time. Until the Zen amp came along, I was a dedicated speaker designer and well aware of the acoustical problems most rooms present so I tried to make sure I had an "average room" to use as a reference. The irony of that was in consistency. A room like this one will never sound the same way twice because your head will never be in the exact (to within a 1/2") spot twice. That presents a continuous level of frustration that many of you share I'm sure.

As you can see, the couch or listening position was near the back wall, the speakers are only a foot or so away from the front wall, although I always DID pull them out to listen. Notice the TV in the window? When you're done chuckling about that take a good look at the wall around it, and realize how hard this surface is. Also the coffee table just in front of the listening position. THIS IS ALL BAD! In doing some model response plots for our room - after the painful decision to sell the couch and loose the TV I might add - we found the ideal speaker placement and listening position for the room and used that as a starting point.

We applied the WASP technique to observe the differences. After doing the Wilson Audio Setup Procedure we averaged in the suggested computer modeled locations and re-did the last steps of the WASP. This we agreed gave the best sound/imaging we could obtain and tried many other ways just to confirm it.

Once settled on the correct setup of all the equipment ( well speakers anyway) we measured the response of the room from the listening position seven ways from Sunday. The results were terrible but typical. There was a large 12 dB problem in the mid bass, a huge 9 dB hole at 80Hz and several high frequency problems as well. At this stage, and armed with this knowledge we still couldn't help but judge the stereo equipment harshly. I remember in particular I grew to hate Dynaudio's new little 6.5" woofer and thought there hundred dollar tweeter was the worst sounding damned thing I ever had to put up with. (Even on tube gear mind you.)

Technically this is what is happening in this now ideally set up "small" listening room: The speakers are about 6 feet apart and the listening chair centered about 6 or 7 feet back, speakers toed in directly at the listener. The distance to the side walls from the speakers is about 40 inches. Since this is the closest surface, it is considered the 1st reflection point. Sound hits that from off axis radiation patterns emitted by your speakers. It then hits the next surface, the rear wall behind the listening chair. From there it hits the opposing side wall on the other channel and the finally hits the front wall behind your speakers where it is now aligned once again to travel directly at the listening position.

The problem with all this is simply that the direct energy from your speakers hits your ear in just a few milliseconds. The same sound that goes past your ear, and around the room to finally reflect back to you from the front wall is delayed in time by so much that it creates confusion in the brain. The brain hears both sounds, one slightly delayed on top of the original and has a hard time deciding where the source of the sound actually is. This is often referred to as cloudy, smeared, flat, etc.

To handle these reflections, we used quadratic prime number sequencing to create diffusers that would spread sound out in a 180 degree fan instead of a direct reflection that a wall brings. By doing so, we diffuse the sound energy at that reflection point dramatically, so the reflections that leave it on their journey to the next wall, are substantially lower in energy. This diffusion also adds a delay to the energy that will help widen the gap between the direct energy and reflected energy our mind tries to interpret.

Naturally we had to put these diffusers on every wall at the major problem points, and we had to design diffusers that worked in a linear fashion across a wide frequency band from 200 Hz to at least 4 kHz. We concluded that the needs of the side walls were different than the needs of the front and rear walls so we designed two sequences for the diffuser wells.

Figure 2 is the side wall sequence. (S.W.A.L.) Note: Pictured during construction. What you see finished is the back of the wells and the diffuser blades only. This assembly will go into a frontless coffin (for lack of a better word) which will allow it to be a free standing (portable) unit and give us plenty of space for the other half of the product - the absorber. {short description of image}

Here is a picture of the sequence used to treat the front and rear walls. These deeper wells offer results lower in the frequency band. These were a particular project to design and build because of the tension between an engineer who couldn't operate a screw gun (Dan) and myself, the more artistic craftsman type. The bottom line is that the tension was worth it in the end. Without both of our strong headed wills these products would have been non ergonomic and somewhat compromised.

All this diffusion will be wonderful for handling higher frequencies from 200 Hz on out to 8 kHz, but in our room the lower frequencies were the big problem. Remember a huge peek a 220, a giant dip at 80 Hz and then a 60 Hz swell (I forgot to mention that one.) To handle these issues we had to first recognize that the bass energy our system produces was abundant (even though it sounded thin and sloppy) And to effectively get flatter bass and MORE bass in the room we had to somehow get rid of most of it! {short description of image}and to do that we needed to absorb it.

Since we learned and measured for ourselves how the low frequencies always find the corners of the room and stay along the walls and floor, those are the areas that we have to deal with. By drinking the energy that accumulates in these areas we can reduce the reflection and thereby reduce the cancellation that creates the holes in your room where there is no bass. Because we know we will effectively be wrapping the entire room with these diffusion units, we knew it would be a perfect opportunity to incorporate absorption into the back of each unit and along the bottoms.

This will do a couple of things. One it will absorb the air space between the unit and wall that will certainly be concentrated with bass energy. Two it will absorb resonance's from the diffuser wells created by low energy and lastly it will give a nice even blanket of controlled absorption throughout the room creating a nice barrier between you the listener and the crappie sheet rock walls of most homes. Boy if they only had these as C.E.S. non of the manufacturers would have had a escape-goat for why their stuff sounded bad. (grin)

{short description of image}So along these lines when we got to the corners where we knew there would be no diffuser units placed, we really got serious and created a HUGE diaphragmatic linear absorbing structure designed to by the mere act of placing it into a corner, eliminate the corner and it's associated side effects. These corner units (C.W.A.L.) absorb clear down to 23 Hz and weigh a 151 pounds! Wanna know a secret... that's exactly what it took to correctly treat the problem. Anything less is a placebo.

At one point we compared one of these units to the more popular light weight tube traps. To make a long story short, we had to make a 300 mile radius to borrow enough of the darn things to match the absorption of this CWAL. It took 22 of them, and naturally there was no place to put the speakers when we were done. This is for real, so please consider it a wake up call, and realize that this is what it takes. When all was said and done, we ended up with three finished products.

From the left to right is a side view of the CWAL, the SWAL, and without a fabric sock is the DWAL. We built 8 DWAL units, and 4 SWALL units, and 2 CWALL units for the room. Actually we built more than that, but the treatment was so effective some of it had to come back out. The process of installing these units and doing before and after listening tests was wonderful because unlike before and after listening tests with pillows, dots, and tubes, we could actually hear a very obvious difference.

The first item was one CWAL unit placed in one corner of the room. Then a week of listening. The model issues of the room changed and you could hear it. The bass was tight now, WAY MORE DETAIL and speed was apparent. Some say it dry cleans the bass! The huge dip at 80 Hz was now a mere glitch, and the 220 Hz peak was reduced noticeably. Then we brought in a second unit and repeated the process of listening and measuring. It doesn't matter which corner the units are in for low freq. absorption, however we found having them on the front wall corners behind the speakers offered a tighter sounding mid bass which the CWAL is also controlling. I had to take several photos and paste them all together to get this shot, and now I can't even find the big version of the picture... Figure 4. This shows almost everything but the rear wall.

Note: The screen resolution in 1997 was 640 x 480 pixels. Digital cameras were just coming out and they really sucked.

paper012

A DOCUMENTARY OF A LISTENING ROOM METAMORPHOSIS

by Steve Deckert
Oct. 1997

paper013

TUBES vs.TRANSISTORS PART II

by Steve Deckert
Oct. 1997

Below is an email I got that refers to our Tube Vs. Transistor articles located in the tube section of this site. I thought is was well written and respect the position enough to say it speaks for a whole lot more people than just Larry.

Gentlemen,

Your posted articles on Tube VS. Transistor amplifier sound are interesting, but they suffer one serious flaw: YOU SHOULD NEVER EVER ALLOW A TRANSISTOR AMPLIFIER TO CLIP!! Just below clipping, a well designed transistor amplifier well have almost unmeasurable distortion. High power transistor amplifiers today are so good and so cheap, there is no excuse for them to go into clipping. The speakers will begin to distort way before the amplifier reaches near its clipping level. The modern MOS FET transistor amplifier can easily reach peak levels of over 200 watts without clipping.

The even-order distortion that tubes produce is still distortion, but some call it "euphonically correct", and, with a tube amplifier you can't turn it off, it's always there. If I want this kind of possibly desirable coloration in my music listening, I would add a tube stage that is voltage starved which will slightly exaggerate this effect (Such as the product the "Tube Head" from PAiA), and then I would have control over the degree of coloration I would like to inject--and I can turn it off, like a tone control defeat switch.

The one common trait all of you Pro-Tube folks have in common is that it is so easy to poke holes in every one of your attempted objectivist assertions (regardless whether you are a member of the prestigious Audio Engineering Society or not). If you keep your Pro-Tube arguments purely subjective, then I have no argument--each to his own.

Larry

My response follows:
Dear Larry,

Thank you for your email! You have just narrowed down what I feel to be the pro - solid state position in only 3 paragraphs which I thought was outstanding!

I think it clear that the two articles I posted regarding the differences between tubes and solid state are an attempt to shed some light on the forever ongoing debate.

I understand where you're coming from on your first position on clipping, but don't forget that using your 200 watt amplifier as an example and listening at a nominal level of 10 watts on power hungry speakers, you would need 1280 watts to reproduce a 20 dB musical peek without clipping the wave form. Granted most music today is compressed and has limiting, but I listen to master tapes whenever possible which have no limiting and more dynamic range than CD's or LP's.

I also agree that most speakers will be into some type of distortion in the above illustration.

The even order harmonic distortion of tubes can be a non factor before clipping in a good circuit. I'm not sure it is accurate to imply that the distortion is always there as a consistent coloration because it is proportional to volume level relative to amplifier power relative to loudspeaker efficiency. Most people can't detect even order harmonics until they reach 3%. In a tube based system with high efficiency speakers and say a 40 watt amplifier, your listening level would contain about 0.2% THD. See Figure 4.

So, this all leading to my personal position on tubes vs. solid state... First off I do not categorically feel tubes are superior. I think each application in unique. For example, I am a musician, and in my studio, I use solid state amplifiers for the mains and wouldn't dream of using anything else. It is just more practical. I have heard many solid state systems that sound really good.

Where the difference comes in is in the specific application of hardcore audiophile listening. By this I mean going into my listening room (where there is no TV or furniture) and getting off on the illusion of a three dimensional presentation. In this scenario I would challenge any solid state amplifier to sound more realistic than for example my Zen amp. For me the goal is to recreate the emotional responses that occur with live music because it's real, not to make damn sure the specs are perfect and then deciding the resulting presentation must also be perfect.

There are two reasons why I think tubes sound better in this application. One is that triodes (tubes) can be operated without negative feedback. The other is because a solid state circuit needs many more capacitors in the signal path than a tube circuit, hence more parts. Also those capacitors are 10 to 100 times larger in value. The combination of all the additional parts and negative feedback will ALWAYS result in LESS depth, less detail, less involvement, less pleasure in a dedicated treated listening room.

Some people think that the goal of a perfect playback system is perfect specs, and some people think the goal of a perfect playback system is one that sounds close to real. These two perspectives are what I feel is really in debate. And the only reason in my experience for the debate is that spec-o-holics have not heard a good single ended tube amp A/B'd with their ideal of a perfect amplifier.

Figure 1 shows a typical Op Amp. One or two of these can replace a small signal tube, like a 12AX7 as an example. Figure 2 shows what's inside the OpAmp. It features around 20 transistors, all direct-coupled with negative feedback. A tube on the other hand would be similar to just one transistor with 20 times the output. Figure 3 shows a Zen Triode Amplifier, the entire audio circuit. In a solid state amp, you typically start with a few Op Amps and then use those to drive larger output transistors, which are almost always paralleled to get the power up and the impedance low enough to drive a loudspeaker. There is virtually nothing to block the back EMF from the loudspeaker voice coil so the real performance of many solid state amplifiers is nowhere near what it is on paper.

There are TONS of CRAPPIE sounding tube amps out there. I would say way more than good ones. This makes it easier for the pessimist to draw a negative conclusion when comparing the two, however I will challenge anyone to the test any time you want to make the trip over here.

The most recent person to take this test owned the Cello Music System, has a treated listening room, and has spent to date over 400,000.00 on fine audio gear, and even worked with Levenson. He has his own successful company doing sound treatment for studios. After hearing GOOD tube gear at my place, he has come 180 degrees and will be the first to tell you I'm right.

-Steve

paper014

TUBES vs. TRANSISTORS

by Steve Deckert
Dec. 1997

A listening room is a room where you listen to music - or is it a room that listens to music? Actually it's a room that plays the music you listen to....

We basically have two things going on here, and we need to clarify which side of the fence you want to be on. There are two basic kinds of listening habits, one of them is called "passive listening" and one is called "active listening". Passive listening is sometimes referred to as "background listening". Perhaps we should call it "hearing" since the person doesn't really actively listen to it.

A Passive listening system can be anything from a clock radio, to a fairly nice home stereo system that seamlessly blends into your decor and gets turned on for the purpose of filling the room with music which can then be enjoyed from anywhere in the room. (We ALL started out as passive listener's with our speakers along the wall or in the corners didn't we?)

An active listening style makes the stereo system the focal point of a room dedicated solely for that purpose. This format allows a much higher resolution of playback to occur, and since the stereo sound field can be experienced in three dimensions rather than two, the enjoyment of it can change into an almost holy experience.

In a dedicated listening room, the freedom to control speaker placement and reflections makes having such a room a scientific experiment to see how much resolution can be resolved.

So, we have two rooms, one is a listening room with no furniture, only your stereo system and the other is (usually) a living or family room with the speakers placed in book shelves, or along the walls somewhere. And yes, I'm sure on occasion super intelligent beings can finagle it in such a way as to have combined the two without compromise.

The bottom line is that many people buy expensive "high end" audio gear and set it (improperly unbeknown to them) up in their family rooms and decide they're audiophiles. They buy and read the high end journals and then wonder what in the world "delineation" and "layers" mean. I'm not saying it's any fault of their own, only that too many people are spending too much money trying to get better imaging and more depth, or just overall better sound and aren't realizing the goal they seek is unobtainable in this scenario.

Buying overbuilt machined connectors and garden hose size speaker wire when the fundamental room acoustics are poor (usually the case) is not a real good return on your investment. Ironically the sonic benefits of high end cables and tweaks are largely masked by poor room acoustics.

I would agree that we're all in a spot because how many people have a spare room large enough to be a good dedicated listening room? I've been there and the vast majority of us are still there. Hell, what do you do? All you can do is perform the WASP speaker positioning procedure (Wilson Audio Setup Procedure) or similar procedure and find the single point in your room with the least amount of evils and then hope you can find a way to live with the results.

Oh, and yes, I almost forgot... there are those $250.00 acoustic pillows you can stick to your walls, or even better than that.... magic "tuning" dots that you can also stick - and that by the shear act of using them will free you of the bondage of this dilemma. In fact I heard that if you paint your CD's green, put an M&M on the top of each speaker and stick a Brazilian carrot in your ass while sipping ginseng tea your stereo will never sound better!

Hmm. how's that for freedom of speech? Anyway, the point is high end stereo gear was designed and intended to be set up in a symmetrical stereo array with the speakers a good distance from the rear and side walls for one simple reason - to recreate the space, depth, and focus of a live performance. You see, IT DOESN'T TAKE HIGH END GEAR to reproduce two-dimensional sound fields.

You know in the early days I didn't used to know what "imaging" really meant. And the expression "sound stage" was curious to me as well. Growing up as a young lad my favorite places to put speakers was ON the wall and in the corners. This gave the most punctual and tight bass response. In those days, bass response was about the only obvious thing that changed from one stereo system to another - so I thought. My ignorance wasn't tied to stupidity, I had just never been exposed to a "sweet spot" where the sound was a good 100 feet deep, twice the width of the speakers and completely three-dimensional. On the day that happened, everything changed. Prior to that day I read about it until I was blue in the face and couldn't relate. Still I find it magical to sit in my listening chair with two speakers in front of me and not hear anything come out of the speakers. The sound just comes out of the air from different spots as though there were actually musicians there!

Okay, enough AUDIO CLASS 101 and on to the important stuff. (Understand all types of people read this web site, not just engineers and audio geeks.)

For those of you who are on the side of the fence with the living/family/TV/listening room thing happening, this is the end of the article. For the rest, read on to get you own holy chamber for audio induced out of body experiences.

It is common knowledge among those who've tried to find out, that the ideal listening room is rectangular and fairly large. The reason for the larger size isn't so you can put your speakers farther apart, it is so that there is more space between your speakers and the reflective surfaces of your room.

In a small room, wall reflections ALTER what you hear from your speakers and always in a NEGATIVE way. At the same time, room dimensions create a comb filter effect that is responsible for variations in frequency response that can reach 12 dB or more as well as change by that much just from moving your head. Ever wonder why your stereo doesn't sound the same way twice? If you have, it's in part the comb filter effect of your room dimensions on the frequency response!

Having a dedicated listening room where the stereo is the main focal point makes it possible to deal with the evils of room acoustics. Even dimensionally problematic rooms and small rooms can be vastly improved if you know what you're doing and why!

I would encourage you to consider a dedicated room, even if it's a spare bedroom, garage, or basement. The science behind it is as fascinating as audio gear and the reward will come to those who really listen.

Lets face it, the average listening space in most homes is inferior. I would say 75% or more simply suck. Most show rooms are no better. CES or trade shows are usually worse. Where exactly do you find a reference for understanding what a good sounding room is! Without being able to actually comprehend how vast the improvement would be to your own gear in a better room it is unlikely that you would spend any real money on room treatment. Add to that the complexity of room treatment compared to a designer power cord, it's no wonder we waist our money on the power cord.

paper015

A LISTENING ROOM -- WHAT FOR?

by Steve Deckert
May 1998 - revised June 2002

Hello Mr. Deckert,

I happen to have read your paper on The Magic Hour, where one experiences a better sound from their equipment at night. All of your points are good solid ones with regards the power line. But even you admit that your line conditioner (a UPS?) gives a consistent 60 Hz at 110 volts. I would imagine that it also cleans out the harmonics and the spits and spats of power line dirt which occurs during the day. (I am going to get one for my tube amp!)

I have perhaps another addition to the conditions which you mention that might also contribute to that magic hour listening zen thing, the level 5.

There is a condition of Earth's magnetic field called the Schumann Resonance's which is excited by lightning, earthquake activity, tornado's, acoustic events et al. The frequency at which the base, or fundamental occurs is 7.83 Hz. Oddly enough, our brain's alpha state is 7-12 Hz. The conclusion can be drawn that since the 7.83 Hz is within the window of the alpha state, that it causes us to be in that state when we are not consciously maintaining the beta state (13-60 Hz, or full consciousness).

The alpha state is one where we are relaxed and "dreamy", euphoric. At night, the amplitude of the Schumann Resonance's is at its *highest*.

Here is another interesting fact: As you know, from Russell Hamm's paper, the harmonic pattern of the triode is similar to a musical instruments pattern. That is, the fundamental is the highest, followed in successive directly proportional levels of decreasing amplitude the second, third, fourth etc. harmonics. Did you know that the Schumann resonance's *also* have the same pattern?

Also, there are seven resonance's (approximately 8,14,21,27,33,38,42 Hz.). There are seven tones in an octave (as you know as a musician. do,re,mi,fa,so,la,ti. The last do is the first of the next octave). Or ears can only discern from 5 to *seven* harmonics. The FFT printout of the Resonance's resembles the EEG pattern of the human brain. I think you know where I am getting at. I am not a numerologist, though.

My opinion, after many years of research in this, is that the Resonance's are responsible for the tube sound, our brain's function at night (and anytime for that matter) and other things.

I say that because, as you know, the tubes input impedance makes it susceptible to EM radiation. The resonance's are EM radiation. I built a solid state amp which takes advantage of this. It sounds like tubes. It has the same harmonic pattern as the triode. No, I am not trying to sell you anything. I am just saying that the design is a "proof of concept".

I also read your reply to another emailer about the tubes versus transistors thing. Bravo! His statement that tubes always have distortion is indicative of his lack of knowledge in that particular area. I have seen tube amp ratings which are exactly comparable to transistors (0.005%THD) in power amps. Pre-amps are much easier to attain this rating (no hysteresis problems from transformers).

As you say, both technologies are subject to possible clipping. However, I also agree that listening should be at such a level as to minimize it as much as one can. On the other hand, I have listened to real expensive SS equipment at low and loud levels, and would still return to my modified EICO tube amp (proud to say I did it myself!) and say AAAAAAH, THAT is music!

Oh well. The war goes on.

Gabe Velez

paper016

THE MAGIC HOUR - PART II

by Gabe Valez
May. 1998

As an audiophile and designer, my listening experiences have had me pondering the connection between the sound we hear and the imagery we construct in our minds compared to the imagery we see with our eyes. The fact that sound frequencies and light frequencies are both waves makes them very similar to each other even if humans didn't exist to see or hear them. The fact that our mind interprets both forms of waves via our eyes and ears to create an image in our consciousness makes our eyes and ears very similar to each other even if sound or light didn't exist.

With this in mind, I began to realize there may be a way to relate some of the subjective adjectives used to describe hi-fi systems by using images. This would be desirable for a number of reasons, least of which would be the reference value, and or possible standard set by it.

For example, fundamentals are present in both waveforms, so if we took a pure high quality image and introduced some phase shifting commonly associated with crossover distortion, we could visually see the colors and textures of the image change. This would be exactly the same as the effects a seasoned audiophile would detect with his ears. The image in the consciousness is the same, yet the audiophile got it from his ears, and the reader of this paper will get it from their eyes.

Combining the two forms of waves, sound & light, to create a performance received by the eyes and ears is a powerful communication. When you go to a concert you can see and hear the musicians as well as the ambiance of the music hall. There is no question how large the room is, where the musicians are located, or which particular ones are playing. Yet when we take away the sight it becomes exactly twice as hard to answer those questions. When we take away the room, and the real musicians and stick your listening room with a pair of speakers it only stands to reason the the difficulty will increase by many fold.

Once the live music has been recorded, reconstituted and finally regurgitated out of your speakers, your room takes over adding reflections of its own that do not match the original music hall. These reflections besides revealing your listening room over the recording, can create a myriad of problems making it difficult if not almost insanely difficult to perceive a clear image in your conscious during playback.

It should be noted that the eyes and ears are approximately equal as senses, and for this reason using both during playback of a hi-fi system is often unwise. Since you'll see the front wall of your listening room, you brain will tell you that you're in your listening room, not at the musical performance. Yet, on a seriously good hi-fi playback system, the ears send a pretty convincing signal to the brain. Sometimes the signal is as strong as the visual coming from your eyes, and then your brain crashes, or at least tension is created.

To see the 3D image of the recording you must not use your eyes.

One of the main reasons, in my opinion, that home theater has become so popular is from the markets basic failure to obtain satisfaction from audio-only playback systems. This basic inability to create a clear three dimensional image comes from failure to comply to the needs and demands of the playback system and room. It's a serious science, not a mass marketable concept. The home theater combines both audio and visual to bring a more powerful communication to the listener, and hence clearer image.

We have all wondered at one point in time or another how the speaker in our TV sets sounds so good when we know its just a cheap speaker. The answer is simple. The visual image received by the eyes and the sound heard by the ears are both interpreted simultaneously by the mind and are both used to create an image or feeling in the consciousness. Vision is a very strong cue. Anytime your eyes can see what is making the sound, the sound will become more clear. This makes it easy to interpret quality that is actually not there, and perhaps the reason so many people are drawn to home theater. In a home, the act of placing a TV between your loudspeakers or placing your speakers against the wall is the ultimate hi-fi sin. It makes it absolutely impossible to create a 3D soundstage.

On the flip side, I have played high quality soundtracks in stereo on a projection screen in my treated listening room and found the sound quality to exceed the video quality by so far that it was extremely distracting. To remove the tension, a 3D hologram would have to have been projected that was maybe 50 feet wide and 1000's of feet deep to get the sound and video quality matched. My conclusion was that two dimensional sound is better suited for watching 2 dimensional movies on TV.

Apex listening refers to serious listening of stereo playback systems using two speakers spaced equidistant with the listening chair and in a symmetrical arrangement with the listening room. The idea being to hear the direct energy (sound) from the speakers without hearing the nasty reflections of the listening room itself. If you are doing serious listening and trying to improve the three dimensional image of your playback system's sound stage capabilities, then this paper may be of some assistance.

It is very hard to explain with words how a system sounds, and even harder to accurately describe how it images. The main reason it is so hard (reviewers) is that most readers only think they've heard what your talking about but in reality have no real reference. Since kind of getting into graphics a little bit as the result of this web site.

What I am going to do is create and manipulate an image to show you what various playback systems sound like, and attempt to explain why.

If you're not sure what a good three dimensional image sounds like, this paper and it's illustrations should give you a solid reference point!

PART 1 - Choosing the reference images

(Note this is the Internet in 1998) It has taken me about 18 months of pondering to decide on an image that could be used as a reference for this paper. Obviously a good quality 3D image, but of what? The first impulse was to photograph musicians playing some music and then run the photo through various filters (algorithms) to simulate various kinds of distortion commonly found in the set up and design of hi-fi playback systems.

The photo of musicians turns out to be too specific. If the discussion is about large spaces and the photo is of a small club act, there is confusion. If the discussion is about the intimacy of a close up three piece and the photo is of an orchestra, there is confusion. The image had to be somewhat generic so as to be applicable to all people, all types of music, and most any discussion. It had to contain all the wonderful things found in your mind when listening to a perfect playback system.. I.e.. the depth, width, detail, layers, tonal quality, balance etc...

After a year of looking for the perfect image, I had to give up and resort to creating one using the technology of the day - a ray tracing program. After creating several object to represent point sources in the sound stage, I.e.. different instruments, I again found these powerful images to be too specific. What I realized is that representative material was needed to mean different things to different people, and this would ensure that the image as a whole was the same to everyone. Kind of ironic. The shapes that I chose are basic so as to remain representative, and are mostly floating spheres.

This paper will no doubt contain dozens of images representing various playback models. The image above will be considered a master that was recorded without a room. By that I mean, if the above image were sound, it would be part of the master tape.

Study the image closely. The black represents space or silence. Pure black is a noise floor of zero. In contrast, the objects floating represent point sources of sound. Together this is called a soundstage. The amount of light level of these objects represents sound pressure commonly measured in decibels. As you look at these objects in contrast with the silent background, they are at a pressure of around 78 dB. With a noise floor of zero (the black background) this would be interpreted as fairly loud. In your listening room, even in the middle of the night when everything is quiet, your noise floor rests between 50 and 65 dB.

Notice that all of the objects (sounds) are in harmony with each other. I didn't make one for example, hot pink. This harmony accurately represents what happens when all the instruments (objects) are in tune. If you study the wavelengths of the 20,000 colors used in this image you will see they are harmonically aligned. To make one hot pink would be to create a flagrant phase and amplitude shift within that object and gross amounts of comparative odd order distortion in the image.

Mathematically I have found that there is little difference between light and sound frequencies. Each color occupies a different bandwidth like octaves on a piano. So when we create a algorithm (circuit) and process the image through it, the alarming result is a fairly accurate visual representation of what these effects would sound like.

The large sphere in the center of the image represents the body or center of the recording. This could be a vocalist, drum kit, piano, or pretty much any sound that is panned to the center of the recording. The smaller sphere orbiting just to the right represents a supporting instrument such as a guitar or another singer, or perhaps a different section of an orchestra. Note both of these objects have reflections below them. These reflections represent the floor, of which there always IS one in all recordings.

The objects with reflections create those reflections by being fairly close to the floor. The reflections give us a reference to the height of the objects. Remember in your listening room with your eyes closed, the only reference consistent in all recordings is the floor.

The three smaller spheres above the larger one represent sounds orienting from a space in the distance. Note in this image with the silent background, it is difficult to know exactly how far back these sounds (sphere) actually are. This is because they are too far away from the reference (floor). This is interesting to note, because when we add the room to this image, the spheres will be very well defined in space and you will have no problem judging front to back orientation of these three spheres. The reason is because we will have added walls or additional planes of reference.

The chalice and the pyramids represent complexity and balance. Although in the image above they are as plain as day, these images have less illumination meaning if they were points of sound, they are quieter. When we add the room to this image, we essentially will be adding a noise floor to the image (recording). This does not mean NOISE NOISE, but rather an ambient decay of the music revealing the boundaries of the space around the music (such as a room or music hall). This ambient background will represent the 50 dB of fill that is missing from the above image. When the room is revealed in the above image, it will add a complexity of its own that will make the pyramids and challis difficult to find unless everything is perfect like on the master tape.

The room image combined with the dynamic image above will startle you as the two combined create a full rich tapestry of sound ( or in this case color and shape). This is important to note because a lot of effort was taken to keep these proportions accurate. The dynamic image in figure 1 with no room is neat but something is obviously missing. You would feel that something is obviously missing too, if you were listening to the same scenario manifest between your speakers.

The room adds as much as 80% to the music so the change is sure to be abrupt. This is of course the original room that the musicians recorded in, not your listening room. Your listening room has effects too, that can account for as much as 40% distortion to the subjective image painted in the conciseness.

Figure 2 will contain the background, or "room" added in the 3D model shown in figure 1. (if anyone knows the author of this image that I used for the background, please let me know so I can credit and compliment his work here on the site) This image will become our reference for this paper, representing the high quality of a well recorded master. The images that follow that will illustrate what happens when.... and you will see the exact side effect in the image that you would hear in your playback system of things like improper room alignment, different audio cables, different amplifiers and so on.

PERFECT PLAYBACK SYSTEM

This reference image in Figure 2 represents the kind of quality, warmth and depth we as audiophiles all long to achieve.

Immersive and grain free isn't it!

This is only achievable with premium sounding gear, properly set up in a very treated listening room and with your head located in the correct position of the apex.

(Figure 2) - A perfect playback system & room

If this image were sound, it was produced by:
High quality turn table playing a virgin vinyl master disc.
Cathode follower tube phono stage hooked directly to...
Zen Amp - single ended triode amplifier running...
very high quality good imaging speakers
Quadratic diffusion and diaphragmatic absorption treatments on all walls.
Correct placement of speakers and listening chair (apex quality)

(Figure 3) - THE ABSENCE OF ROOM TREATMENT

room reflections distort and homogenized the image

This image represents as good as it can get without major room treatments. Still pleasing, still grain free, just difficult to define the shapes and impossible to hear some of the recording. Note some of the objects (sounds) have disappeared! Also notice the sense of depth has been compromised.

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PART I - Paper regarding the subjective effects of apex listening in a variety of system models using imagery.

by Steve Deckert
1998

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PART II - Paper regarding the subjective effects of apex listening in a variety of system models using imagery.

by Steve Deckert
1998

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HIGH SOUND PRESSURE LEVELS

by Steve Deckert
July 1998

Consumers of hifi gear seem to gain all of their knowledge about it from magazines and sales people. Manufacturer's literature certainly being at the heart of it. That means the knowledge is more about what's popular than how it actually works or if it actually works in some cases.

You would think that the equipement pictured here would be superior to magazines and published specs for gaining the real facts yet it to suffers from the same miss-understood interpretations. I am pretty sure any electronics engineer will be happy to tell you that using ohm's law, watts are watts be it solid-state using pulse-width modulated power supplies or tubes using linear power supplies. The reality is that watts are not really watts in audio amplification because there are so many variables that determine what each watt can accomplish. High efficiency solid state watts and tube watts are usually an apples and oranges comparison.

It pains me to see that every day someone makes a purchasing decision based on specifications. Besides RMS power, I'd have to say that THD is by far the worst overblown subject in audio. Many people who call me haven't had the opportunity to realize that there are two basic forms of distortion encompassed by the spec: THD, and that one can actually sound good. They don't realize that tubes are very different than solid state devices and that distortion and power output are tightly linked.

When people discuss watts, they equate it to how loud something will get without audible distortion. How loud an amplifier gets compared to another depends on its ability to drive a given speaker load. It is possible to have a 10 watt amplifier get a pair of speakers louder than a 100 watt amplifier based on this reality.

-Steve Deckert

ZEN TRIODE POWER RATINGS

The Zen Triode for those who don't know, is not an ordinary amplifier. It's sole purpose in life is to see how pure we can reproduce sound. That is the reason for its size and power output. It's a classic example of the phrase "Less is more!"

Based on the observation that the less parts used in an audio circuit the less coloration the circuit has... And based on the observations that more powerful amplifiers require and use bigger parts and generally more complex circuits - it's easy to conclude that larger amplifiers while having higher power numbers will also have higher coloration's.

Figure 1 - If you made an imaginary line chart with Fidelity on one end and Power on the other, you could design an amp to fit anywhere in that line, but regardless of where you chose to put it, you would be balancing between the two. That's a classic example of the phrase "Good sound is a balance of compromises" Too far on the fidelity end and you don't have enough power to drive anything, hence it's useless. Too far on the power end and you no longer have a class A high fidelity amplifier.

I found during the development of the Zen Triode Amp that there is a magic spot on the line of power vs. fidelity where the balance of compromise is minimal. Guess where on the line the Zen Triode Amp sits?

ZEN TRIODE RMS POWER OUTPUT

When this amp was first released we listed the Zen Triode is around 5 watts per channel. Since then competitors have jumped at the opportunity to interpret this as RMS (Root Mean Square) power output. After all that has become the standard way to determine the power of most amplifiers albeit far less meaningful in the tube world. In fact around here (in the tube world) and in the spirit of good Zen thinking we found that RMS really stands for "Real Meaningless Spec". It would certainly go against the theme of our little amplifier to post a lot of real meaningless specs when we can instead post a lot of real meaningful reviews.

It is not my intention to apologize for misleading the public with a 5 watt rating, because it was never stated to be RMS power. RMS power is what you read using a 1000 cycle pure tone into a non inductive "dummy load" consisting of large silicon resistors. This makes a wonderful reference to the designer when comparing one amp to another, or modifications within a single amp. However it makes a rather pathetic reference of how music will sound through it or how loud it will get into a given loudspeaker load.

Obviously music is not a pure 1000 cycle tone, and speakers are not large non inductive dummy resistors. Our rating of 5 watts is a peak power rating that takes into account things like: Peaks in the music and the amplifier's ability to generate power peaks in excess of it's RMS abilities not to mention distortion signatures and clipping characteristics. It also takes into account the fact that speakers are ever changing complex loads that behave very differently than "dummy loads". We felt based on the less than clear common interpretation of RMS watts that a more realistic "music power" rating was in order.

In the picture above you can see we have the gear to get anal about specifications, but have always chosen not to complicate our sales approach or your mind with excessive specification information which we feel is commonly misinterpreted. Figure 2 shows the RMS output of a single channel of our Zen Triode Amp to be at 2.38 watts just before clipping. When the sign wave starts to flatten to a point where the listener can detect unpleasant distortion the unit reads around 3.40 watts RMS.

WHY DIFFERENT RESULTS FROM DIFFERENT PEOPLE?

If you have been enjoying measuring the RMS power of the Zen Triode amplifier, please be aware that output tubes (all of them) vary in emission. A matched pair of tubes simply means they match each other. It doesn't indicate if the tubes tested strong or weak. The difference between a weak and a strong tube in the case of the 6Bq5's and or SV83's can be enough to vary the reading by almost a watt. Additionally the voltage drop across the rectifier and the voltage at the wall outlet all make a substantial difference. Of course when you measure RMS power you have to pick a level of harmonic distortion that is acceptable for the design.

For the RMS tests pictured on this page, we used a matched pair of tubes (only one of which is measured at a time during the RMS testing) that tested at 7500 micromhos. This is done on our Hickok model 539a tube tester with the bias setting at 2 volts. We match all our tubes here in direct micromhos using this classic military tester. 7500 is about ave. for the SV83's that we've tested (around 750). Some are as low as 4840 and some as high as 9750.

So you can see just the tubes themselves can account for differences in RMS power measurement of a Zen Triode Amp.

SPEAKER LOADS ~ IMPEDANCE and SET's

There are some stereotypes of how an amplifier drives a loudspeaker that relate specifically to the impedance curve of the speaker. The stereotype is that most amplifiers, especially low power single ended tube amps, have difficulty driving low impedance loads. In fact this has gotten so overblown that speaker manufactures are now listing the minimum impedance right on the specs. Without fail everyone that calls me about possible speaker prospects is concerned that they're speaker selection may not have a friendly impedance curve. Well, friendly to who? The Zen Triode amplifier is not like other amplifiers, if it was it wouldn't carry the name Zen in the title. The Zen Triode is perfectly happy with low impedance loads and will drive nearly a dead short.

This is certainly against the grain, especially for single ended tube gear, but was by no means an accident. Since one of the biggest problems with low power single ended amplifiers is their ability to drive difficult or moderately difficult loads, it's no wonder that the SET market is so small and overlooked. It would seem to me that when you have only small amounts of power to work with, you certainly wouldn't want to handicap yourself further by having the amplifier's power curve suffer at the low end of a speakers impedance. Doing so would mean that at a speakers resonance, where the impedance is high, the amplifier would have no problems or even put out more power. But when it drops the amp begins to have trouble.

Ideally, the amp would put the same power at any given frequency and the speaker would have the same impedance at any given frequency but this is impossible. Industry has focused on this for many years creating high power amplifiers with lots of negative feedback and high damping factors to make them "NOT FEEL" the speaker and thereby not be so affected by its impedance. Speaker manufactures have also focused on this by creating complex crossovers with Zobel impedance matching networks that yield a flatter impedance over the frequency bandwidth of the speaker. The problem with this is POWER. To do it requires lots of power. We already know that high power amplifiers are not as pure on the fidelity line and have more colorations and less detail. Speakers with overly complex networks become grossly inefficient and thereby require lots of power just to sound good. If you throw only 1 watt at these units, some of it is spent as heat in the crossover before it even gets to the voice coil of the speakers.

In the world of Single Ended Triodes, it's all about the first watt, and the magic that lies there. This is why when used with conventional speakers most SET amps fall short of delivering a good performance. The pairing is not unlike trying to ask your car to start after pouring orange juice into the gas tank instead of gasoline. My solution to this problem was to do things backwards and design an amplifier that put out more power into low impedance than into a high impedance. This approach certainly won't solve all the obstacles of pairing single ended triode amps with speakers, but it will make it possible for most anyone to find out what single ended is all about.

After marketing the Zen Triode for 2 years, 90% of our customers were able to use a Zen amp with their existing speakers. Speakers that were designed for today's solid state power houses. And while I'm sure none of them get LOUD like a big amplifier, I do know that I was successful in letting these people not only hear what single ended triodes were like, but gave them one that sounded better than similar units many times the price. That by the way, is what gives me the most pleasure, and why I enjoy my work so much!

When I said I wanted to "Design an amp for the masses", this was what I meant.

HOW DOES IT WORK?

The primary thing that makes the SE84B unique is that it was not designed with a calculator to effect the max. power. In other words there was no greed involved when balancing power output against fidelity. A math guy will always match the output transformers primary impedance against the plate curves of the output tube for max power and lowest distortion.

In fact we had to make our own power transformers to come up with the right impedance for our needs. Our custom hand wound air-gapped grain oriented silicon steel output transformers have a primary impedance of 9800 ohms and the EL84 / SV83 output tubes would rather see 1/2 to 1/3 of that. This combined with a single 6 ohm tap gives ideal clipping characteristics on the average speaker load. Lets face it, 8 ohm speakers are often closer to 6 ohm and with a six ohm tap the Zen can drive either 8 or 4 ohm speakers. The clipping characteristics of this design are so graceful that you can't hear when the amp is soft clipping. It takes a hard clip before you can actually hear it.

It is this gracious clipping and lower distortion from the output transformer that makes it hard to give a power rating that means the same thing to everyone. If you were to measure it like a solid state amplifier at .001 % distortion, you would have below a watt. When the engineer measures the amp, it is his interpretation of the waveform on the scope and or the distortion threshold he sets that determines the RMS output. Consumers used to hearing that distortion is a bad thing from large solid state manufactures have been grossly mislead to assume that this would apply also to tube gear. I would guess that most people who listen to a good SET amp, Zen included, are pushing between 5 and 10% distortion and don't even know it. Reason: Even order harmonic distortion sounds good, is more natural. Like playing a two finger chord on the piano. Odd order harmonic distortion (the type solid state circuits generate when clipping) is the exact opposite. Nothing good or pleasing sounding about it. In fact it rather sounds like sandpaper going through a meat grinder. Or like playing the wrong notes on the piano. It creates ear fatigue by its very design because nothing God created on this earth related to music that I can find creates odd order harmonic distortion naturally.

In the power tests using the same output tube, the Zen Triode amp performed with higher RMS output into low impedance loads. For example, a 16 ohm load yielded just under or at 1 watt RMS before measurable (not audible) distortion. (The waveform shown in the picture) An 8 ohm load yielded around 1.5 to 1.9 watts RMS. A 4 ohm load gave us around 2.38 watts RMS and a 2 ohm load gave us around 3.21 watts RMS. In the same tests, the amplifier was bridged using our series bridging technique made possible by floating the outputs. In this configuration the now mono amplifier exactly doubled all the figures above.

SUMMARY:

The importance of audio specs are overblown. Specs for solid state and tube amps don't give the consumer even a hint of an idea what the unit will sound like or how loud it will actually get before the sound stops getting better as you turn it up and starts getting worse. RMS to the end user i.e.. the consumer of tube gear means "Real Meaningless Spec" and worse than that is THD, and worse than that is DAMPING factor. Please don't let the math guys trip you up with rigid specifications because the slightest tweak of the knob on our test gear (and theirs) can change the readings - making it largely open to interpretation.

Remember RMS does not account for Peak Power, Instantaneous Peak Power, Clipping characteristics and the distortion level where RMS is measured is open to the guy doing the measurements. The industry who has been in a who has the lowest distortion competition for the past 70 years has completely missed the boat on sound quality. If someone is telling you the Zen amp is only a watt, smile and say "well if that were actually true, then it makes it even more amazing that it sounds so much better than yours."

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ZEN TRIODE AMP POWER MYSTERY UNRAVELED

by Steve Deckert
Sept. 1999

"I once had a 350 watt triode amp driving some Bose HPM100's." Did I bother explaining to the guy that Bose never produced a HPM100, and that in fact the HPM series was a Pioneer speaker, or that audio triodes don't get that big and that if they did he could never afford one? No way. All I'd get is an argument.

I've had many years to notice that audiophiles get around cool audio gear and feel obligated to share delusional stories of former audio exploits. In fact most audiophiles have experienced this phenomenon, and likely participated. It's almost involuntary, a subconscious device used to sort of rank yourself compared the coolness of the gear you're ogling. For example, to approach a Wilson WATT System owner and to mention, "I have a modified Haffler amp," is to say, "I realize I'm nowhere near as cool as you, but at least I have a greater appreciation and understanding of your stereo than you'd expect judging from my Michelob T-shirt."

That's OK. But I truly have no idea where people like Mr. Audio dream up their stories. "A 350 watt triode? Yea, I knew a guy that had one of these in his living room." Sure you did---it's just that they called them radio tower transmitter tubes back then and required a complete HVAC system to cool them, not to mention the tube alone is a couple feet tall. "And it had giant heat sinks on the back." Oh, I see, so now it's sold state triode huh? But there is no... oh, never mind.

I'm not making this stuff up, The insistence upon the inaccurate is inexplicable, yet often predictable. Probe deeper about the gear in question and you'll find that .005% DISTORTION is always involved. Speakers are always HUGE. Wire is always SPECIAL and connectors are always GOLD. Adding SILVER SOLDER to virtually any component is always good for credibility too. If you field a correction, the storyteller will certify that "It was a rare special edition." And besides, the gear in question is always either the best sounding in the area or at least the only one (or the first one) sold in town. Countless neophytes have insisted that their stereo could do a 130 dB in their room. Right. To prove it, you'll hear tales of blowing away a Krell, Levinston, or Sonic Frontiers-- those being a few of the apparent standards by which all performance is judged. The longer ago it was, the better it sounded. Nine times outta ten, it was sold way too cheap ("It'd be worth $100,000 today.") or blown up one night while drunk. That I wholeheartedly believe.

You'll also run across what can best be described as the urban myths of the audio world. My friend, unfortunately a one-piece rack system owner, has a favorite: CD's blow away records. No. I just nodded when a recent admirer of my custom built corner horns (the only two in the world---built by myself) pointed out that they were available in a rosewood finish about 6 years ago. And did you know that Mac uses thicker wire than HK? Hear tell, every significant amplifier was "grossly underrated" in advertised power.

I suppose the tall tales stem from years of overstatement in high-end audio publishing. Glorification sells. Add up a bund of nebulous audiophile buzz words and you're sure to sound like an authority. So when an onlooker strings together a set of incongruous audio facts, I have to step back and realize that he's simply uninformed and not just plain stupid. All he really wants to do is admire a great sounding stereo and feel like he's part of it. For many audiophiles, the attention is what they really love about the hobby anyway. That and the ridiculing of those who know less than they do. So it all works out in the end.

The point of view above is mostly paraphrased from a letter originally written by the editor of Car Craft magazine---about car lovers. I just switched topics as a sort of twisted form of entertainment.

I guess what makes it so interesting is the human nature behind both is exactly the same. The original letter started out "I once had a Hemi 350 in a '66 GTO with a 400 four-speed." Of course there is no such thing and so on the letter goes.

On the flip side, I find it interesting that cars and amplifiers are so similar. This summer I came across a '72 monte, pictured above, and have spent the whole summer tweaking it. A process that began with a new set of aluminum 2.02 heads. By the middle of the summer after having accumulated 3 and a half carburetors and rotating them on an almost weekly basis, I started to realize just how similar this is to tweaking an amplifier.

Finding just the right fuel curve against the weight of the car, gear ratio, tire diameters, horsepower and torque to achieve just the right throttle response and feel turns out to be an endless quest of infinite possibilities. Just like building an amplifier and getting the perfect signature that makes everything come together and sound right. Perfect sound and the way I want my car to feel when I drive it are both subjective. The infinite variables that combine to yield the result are indeed infinite. This means that success can be measured in direct proportion to the amount of time you spend trying the combinations, which are remember, infinite.

Another thing I realized is that there are two distinct levels of performance and grace in auto tuning. Carburetors are where this became obvious. Because air temperature, gas quality, and altitude all affect the fuel curve of a carburetor, manufacturers can only set them up with so much resolution and accuracy. To get one perfect, modifications far beyond the "known" adjustments are required. At one point, when this car project began I found myself buying the best heads, the best carburetors, best everything and putting them together per the manufacturer's recommended combinations. I was disappointed in the results. Then I decided I need to find a guru engine tuner, I know some must exist somewhere. The top commercial name that came up was a guy who built cars for the speedway and was said to be the best. Certain he would do more and know more than I did, I took it to him to have the valves adjusted and the carb and timing tweaked. I was very disappointed. The car actually ran worse than when I took it in. Hey wait a minute, this seems like audio...

I was in a grumpy state because I actually knew more about engine tuning than the appointed "expert" and now was going to have to do it myself. Unsettling to say the least, because compared to the guru I envisioned, trust me I didn't know shit. This obviously means that the experience or perhaps "quest" would be a better word, is going to be just like audio. And like audio there is an underlying level of knowledge that seems to contradict popular knowledge and I was going to have to find it.

Everyone calls my Monte the "Zen" car because I went though the same process of relentless tweaking and experimenting on it as I did during the design of the Zen amp. Ironically, or maybe not, they both came out very similar to each other and I'm not sure which one I enjoy more. Riding in the car is not the same as driving it, so few people get to share the experience. The Zen amp on the other hand I get to share with everyone, and it's only human nature to enjoy sharing ones discoveries. For that reason it's safe to say I enjoy building and selling the amps more.

Is there a point to all this? Not really. That's why these papers fall under the title:"Ramblings about Audio."

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AUDIOPHILES IN AMERICA

by Steve Deckert
Dec. 1999

There is a good reason why most speakers sound like speakers. It's because most designers follow a specific sequence of mistakes that lead to mediocre sounding results.

Let's face it, if you're going to design a do-it-yourself speaker the first and obvious problem is going to be getting the woofer(s) and the cabinet tuned for flat extended frequency response. Some will choose a cabinet and then model different drivers in it, some will select a woofer and then model different cabinets for it. Both will then design the crossover based on the published specs of the drivers, choosing the best looking spot for the crossover frequencies and then design a network to these predetermined ideals.

They will then order the parts and assemble it. Some will be amazed at the best sounding speaker they've heard, some will be a little unhappy and start tweaking the design. This procedure for speaker design is a recipe for mediocrity. Anyone can do it, almost everyone falls into the trap. To reiterate, you can't design your speaker based on published specs. Some of them are usually never accurate, and others too complex to mean anything in your specific situation.

For example, considering polar dispersion plots of tweeters and midrange drivers as you decide what type of crossover and so on is futile. Drivers all have signatures that defy known specifications, but are in fact the sum of those specifications. You may have all known data from NASA grade test gear on a particular driver, but no accurate way to compile that data in your mind so as to hear what the driver will actually sound like. You actually have to listen to it.

Listening to it is the only accurate way to draw a subjective description of it's sound or signature. And of course the front baffle size, shape, material and angle will also change the signature of drivers, especially midranges and tweeters. So even if you have the drivers in your hand and have listened to several frequency sweeps, the signature you determine the driver to have is false because it's not yet in the cabinet. Once you have the driver in the cabinet, the new signature you determine the driver to have is also false because you haven't installed any crossover components yet. Suppose you installed a cap on the tweeter, and determine the drivers new signature, you still have no idea what the final signature will be because you haven't added the midrange, or woofer. Any drivers and crossover components you add to the circuit will affect every other part of the circuit in the way the current and frequencies divide. So in the end, all the math in the world will not predict accurately how a speaker will sound, and if it will image or not. Although if followed will get you close, but also become a limiting factor of how far you can go.

Added to these variables, as you try to first determine the signatures of each driver, is the room acoustics which will affect the perceived result by at least some 40%. And I've almost forgotten to make it clear that the proper way to design a speaker is by identifying the individual signatures of each component and combining them in a way that is complementary. This can only be done by human ears. A tweeter that has a signature you've determined to be a little sharp on the very top end may be less than ideal when measured against itself, however suppose your midrange drivers is a little bloomed out and overly warm sounding. Depending on the overlap and slope of your crossover, the two can create complementing signatures and actually sound great.

The way to design a mediocre speaker is to use all the math you can and model everything from the crossover to the cabinet to create a perfect result.

If you want a great sounding speaker, you can't design one this way, for several reasons. The first is that published specs on drivers are never accurate. You will have to pick the drivers with somewhat of a casual attitude and then buy them. Once you have them, you'll have to measure them yourself and see exactly what the specs actually are. Be prepared to repeat this process. That means you may be setting some of the drivers you've purchased on the shelf and purchasing new or different ones hoping for better luck.

Some basic steps are as follows:

Once you have the drivers in your hands, and after you've measured the Thiele Small parameters of at least the woofers, you are ready to start designing a crossover. Now that you can plainly see the discrepancies between the published specs and actual measured specs, you can be glad you haven't built the crossovers yet. The first step in designing a crossover is becoming familiar with the characteristics and signatures of each driver. To do this, you simply hold it in your left hand and using a frequency generator, start sweeping the frequencies to extremes of each drivers bandwidth and LISTEN.

You will be listening for smoothness of frequency response. Use your ears, not measurement equipment because the signature of each driver will be superimposed on the frequency response yielding unique sonic results that can't be seen in computer modeled or measured plots.

For example, on the woofer, you will find it's FS just by feeling and looking at the woofer while you sweep it. As you sweep, pay close attention to the sound. Sweep very slowly and hunt for peaks and noises. This process should be documented on a piece of paper by listing the results. For example:

30 Hz ~ 300 Hz - very nice

300 Hz ~ 600 Hz - good

600 Hz ~ 2300 Hz -good

This means that around 300 Hz there was a change, either a peak, or a noise of some kind. Another one at 600 Hz and a noticeable roll off after 2300 Hz. Do the same test on your other drivers (mids and tweeters). Circle the Zone of response that had the sweetest sound. When you find a peak or noise, play with the driver by squeezing it, angling it, shaking it, tapping on it, anything you can do without damaging it. The objective simply to see if anything you do changes the characteristics of the peak or noise. This process usually leads to tweaking the drivers before they're ever installed in the cabinet. For example:

Most stamped frame speaker frames resonate or ring at certain frequencies that depending on size and mass hover between 200 Hz and 1200 Hz. Adding damping to the frame can reduce or eliminate these types of frequency response glitches.

If you're using dome tweeters and or midranges, you will have to install them in the cabinet and sweep them again. Expect large changes in frequency response based on the interactions of the baffle refraction. The surface material, i.e.. wood, felt, can largely affect the signature of the dome drivers as well. Remember that signatures are not found in specs, polar response plots, or transient response tests. There is no way to tell from specs the sonic changes that occur between fabric domes and silk, poly, titanium, or phenolic domes.

From drawing notes on paper you can tell the sensitivity of each driver in relation to each other simply by selecting frequencies that overlap and swapping drivers. For example, the midrange may well go up to 10K and the tweeter may well drop down to 2K, so setting the frequency generator around 5K and A/B the mid and tweeter will tell you which one is louder. The armature trained ear can hear 3dB increments, so if you can tell one is louder, the gain was at least 3dB.

Draw yourself a crude response plot on your paper for each driver and as we said, circle the areas that sounded best. This will help you determine where the best crossover frequencies would ideally be. Once you've come up with a plan based on the real data you just measured with your ears taking into account both efficiency and signature, you can rough in a crossover network. Remember, the midrange and tweeter have a large overlap, and both can play the same frequencies, so in the area of overlap, which one has the most pleasant signature? A question only your ears can answer, and one that must be answered before designing the crossover.

Designing the crossover can be a successful experience provided you keep it simple, at least at first. Using your calculator or computer select the components for either a 6 or 12 dB network that approximately will hit the ideal crossover points you want. If your speaker is for high power applications use the 12dB networks, but if your using lower power amps and higher efficiency speakers you have the option of using either one. When your caps and coils arrive, start with the woofer by installing it in the cabinet and sweeping it several times. Now how smooth has the response become, what changes have taken place. If you like to measure things, you may be amazed at how the impedance curve changes once you have the woofer in the cabinet. Playing with temporarily sealed openings in the cabinet will make radical changes in the the impedance curve, as will the final tuning. Assuming your network is either 6 or 12 dB you will have a coil for the woofer. Once you are satisfied that the woofer is tuned to the cabinet you should sweep it several times with the inductor and without. Notice the signature of the woofer changes completely with an inductor in the circuit. If it makes it sound worse and you have unusually flat response you can and should consider throwing it away.

The following must be done with music, not test tones.

In most systems the mids and tweeters are higher sensitivity than woofers and will need to be padded. This can get complicated with a calculator so you're best bet is to assemble a variety of caps and ceramic resistors, and using alligator clips and test leads, clip together the 6 or 12 dB network that you purchased the parts for and hook up the speaker. Play it a low levels and use this first sound as a starting point. With respect to the polarity of the woofer, the midrange and tweeter (other drivers) can be either in phase or out of phase by 180 degrees. If you have more than one driver such as a midrange and tweeter, you should experiment with changing the polarity of each one at a time and listening to what happens. You will notice large shifts in frequency response and presence. The various combinations possible by doing this can yield either a forward or laid back sound. The reason this happens is timing, or phase angle. The phase angle of a speaker changes with frequency, and in the case of the woofer, affected dramatically by box design and tuning frequency.

Remember, at this point you have what looks like a pile of spaghetti on the floor and it's better if you do not know which way is theoretically correct as far as polarity goes. Just listen. Once you have determined which polarity combination sounds best it is time to start balancing the output of each driver in reference to the woofer. This usually involves padding or shifting of crossover points or both and can be quickly accomplished with a variety of 1 ohm to 10 ohm ceramic resistors. The resistors should be used in series with the drivers. (That's mids and highs only - not the woofer(s) This process should be done while listening to the speaker and simply involves swapping out values until you find something you like. Remember that padding a driver changes it's impedance and that means your pre-calculated crossover points will also change. This could be good or bad, so it's nice to have a variety of capacitor values to swap in and out of the circuit as well.

This process can take anywhere from a couple hours to a couple days and when finished, you'll have a really scary pile of test leads and parts connected together in front of your speaker. It may have been difficult to keep track of the circuit as you swap parts in and out, and that's okay. In fact if the audio gods favor you, you will find that when you try to draw the schematic you'll discover that you hooked things up wrong or at least differently than planned. If this happens and the sound is good, you can smile in the knowledge that you're probably on to something.

This brief paper is just an attempt to deprogram do-it-yourself speaker designers. Remember your ears are more expensive than the best test gear, and work better. The reason we favor this design process is because the actual number of real variables is overwhelming. Things like Signatures and coloration in drivers will change your subjective interpretation of frequency response. A good example is the way a poly dust cap can superimpose a dryness in the midrange that is often misinterpreted as better transient response.

For more in depth information about this technique, you can visit the web page where using this process I design a do-it-yourself speaker that you can build and compare with other speakers to demonstrate the results. In fact, if you truly want to graduate to a level of understanding that yields superior results, try this: Design your crossover before you buy your drivers, like you normally would, based on the published specs and other people's comments. Then put it in a drawer somewhere and proceed with the above technique until your finished. When you build the second speaker, install your pre-designed crossover and compare the results. You should find the experience enlightening and if successful a little embarrassing.

paper022

HOW TO DESIGN A SPEAKER

by Steve Deckert
March 2000

In this article, I'd like to show anyone who's serious about a listening room how to set one up with little or no room treatment. Obviously with the complexity and variety of room acoustics out there, your results may vary, but odds are you will find it an improvement over doing nothing!

If you've spent much time on this web site, and looked into our room treatment sections you may have discovered that room acoustics is a fairly serious science and it's usually not solved by random placement of room treatment products. We feel that your room is usually around 60% of what you hear coming from your stereo. Most people either don't believe this, or just haven't grasped it's reality.

It's hard to stomach the fact that so many audiophiles concern themselves with connectors and power cords and all the fancy tweaks when these at best pale in comparison to the effect of room acoustics. The biggest problem is most of us don't have a room we can use for JUST our stereo and since we've never had one, or heard our stereo in one, it's hard to really grasp what the differences would be. For many of us, if we could some how magically hear our stereos in a dedicated properly setup room for just a few seconds, it would be enough to suddenly justify having one. Basement rooms would be built, garages would be converted, maybe even kids kicked out to gain use of a bedroom!

All I can say, is that in a decent room where everything is ideally setup, the layers and layers a soundstage take on is so holographic that music takes on a whole different side, one that is highly addictive. So if this is you, or you can find a small dedicated room, or have the luxury of arranging your living spaces around your stereo, read on.

This story starts with a dedicated listening room, with thick carpeting, real plaster walls, high ceiling.

In our search to treat a conventional listening room to a degree that the changes were easily noticed, we ended up using quadratic theory diffusion carefully balanced with diaphragmatic absorption to deal with the reflection points and room peaks that are responsible for trashing good imaging. This was a little more serious than buying a couple tube traps.

The final result of what we did was a project that was shared with everyone in the form of D.I.Y. Blueprints. These are available in our online catalog. To effectively treat our room we had a total of 14 units that added over 2100 pounds of mass to our listening room. And that is actually what it took to effect a noticeable result, and turn a rather small 13 x 15 foot room into a good performer.

Last year when we built our new shop for manufacturing our Zen triode amps, I needed a listening room there for testing and evaluation. Here was an opportunity to build a listening room from scratch... you can imagine the things that were going through my mind. After dusting off the Masters Handbook of Acoustics and reading it cover to cover three more times, I had a healthy fantasy of what I could do and it was lush let me tell ya. After all, I would be entreating customers or potential customers there and first impressions are everything.

Then the lease was signed and I found myself building the interior of our new place all by my lonesome. Between the stress of moving a business without problems and the reality of not wanting to give up 16 feet of my building for a listening room, I gave up and decided to slap together your typical drywall room at a width of only 12 feet. Between the concrete slab, drop ceiling, and cheezy walls I knew it would be bad. I thought, hey... I'll create a worse case scenario here, and then somehow make it sound good just to encourage the REAL world folks who would likely find themselves in similar situations. So with that, I made the room a depth of 22 feet which if you have the Masters Handbook of Acoustics, you would know is just about the worse ratio you could have for good sound.

With rational in place, I built my listening room/office and found myself standing in an empty hard room, concrete floor, measuring the decay time of a hand clap. It was ridiculous, I don't even remember now, but not 50 ms. I would be shooting for. Something like 2.5 seconds was the minimum reverb time. Well, this was certainly going to be challenging I thought as I continued to handicap myself by installing carpet with no padding.

Once finished, I grabbed a pair of speakers, a Zen amp, and a CD player and tossed them into the room to get an idea of what was going to have to be done. I hit play and then stop. The second of time that elapsed between the two buttons almost made me sterile. My ears were so offended that I took everything back out instantly and went home. Later that evening the realization of what a challenge it would be to treat this room was starting to set in. But hey, if I can't do it, how could I expect anyone else to conquer their acoustic demons?

I decided that I wouldn't have time to build more room treatment, so I was going to have to steal the units from my own personal listening room and take them over to the new place. Saddened at the thought, I told myself that it would be so good over there when I was done that I'd do my listening there anyway. (Yea right..)

I dropped all 2150 albs. of diffusers and bass traps into the room and dragged another pair of speakers back in for test number two.

This time when I hit play, it took around 5 minutes before I ran out of the room in disgust. It was frankly the worse sounding room I've ever heard in my life! I was paralyzed with Father Murphy-itis. Intensely annoyed for days, I avoided the issue by not entering the room.

At the same time I was able to hear my own stereo at home minus the room treatments. That didn't help my spirits any except to say the room treatments really really worked well, and the room over at the shop is just really really really really that bad.

In the mood to quit goofing around one weekend, I got serious and measured the room at the new shop. As suspected the difference between a 50 cycle note and a 5000 cycle note was a gain of almost 20 dB! Now that's hot. In calculating the amount of absorption I would need to kill this problem I realized that it was almost exactly the density and area of the carpeted floor had there been good padding under the carpet. Now with over 2000 lbs of stuff in the room, I wasn't going to have padding under the carpet so I started absorbing it in bits and pieces and in a variety of ways. Padding would have been so much easier.

Once completed, and after building a permanent bass trap out of an unused closet, I got the room to become fairly flat with decent response at 30 cycles and some sense of order. It was now listenable, and as the weeks went on with continued tweaking and creative room treatments I had a room that was at least 800% better than before I started.

A picture of the end result can be seen in figure 1. It was a listenable room now. However my personal listening room at home has lost its luster and no longer seduces me into hours of evening listening. In fact, I abandoned it for almost a year.

On a whim one evening, I decided to set up some gear in my home listening room again fairly certain I had forgotten how good it used to sound by that time. Only this time I set it up diagonally which is something I had never done at home in any of my listening rooms. But the more I thought about it the better the idea seemed to be. So I went for it and took a pair of speakers (that were exiled from the shop because everyone hated them) home and set my room up.

The result really caught me off guard. Before I did it, Still having the tape marks on the carpet from last year, I set the speakers up on the old marks and listened in a conventional way. That's when I learned my own acoustic memory is longer than one year because it really sounded nasty. It sounded nothing like it used to with the room treatment. But the exact same gear set up at a 45 degree axis within the room sounded better in almost every way than the room did the year before when it was set up conventionally and with all the room treatment diffusers and such.

Well, what do you do when your sitting in a naked room with two waynky-dink speakers that no one likes and you're getting better sound and imaging than you've ever had before without room treatment? Well first you panic, then you resolve to tell noone and then you desperately try to figure out what happened.

Along the way of figuring out what happened I made some revelations about imaging that I think you may find interesting.

How many of you have heard your stereo or someone else's with a strong center image that exhibits good depth? Now how many of you have got that center image to shift from one side to the other when you move your head? Ever wonder why that happens? I certainly have. In fact I have an ongoing experiment in progress trying to resolve that very issue. In any case, the bulk of that experiment resulted in my own recording studio so that I could experiment using recordings that I created and mixed down myself. I have found the reason for the shifting effect is two fold, the way it was recorded and an effect from your own room acoustics.

I will probably do a paper, or several, on recording techniques so I'll leave that out here and just focus on the room effect that I feel accounts for most of the effect anyway.

As it turns out, the reflection points that triangulate around the room are vastly different when set up on a 45 degree axis. In a conventional room, the first 4 to 6 reflection points of a speaker are on the wrong side of the room. In other words the direct energy from say the left speaker will have its first four or five reflection points on the right side of the room. This often ends up with reflections 8, 9 or 10 on the rear wall behind your speakers staged to pass back by your ears. Since a conventional room is untreated, these reflections don't lose much energy and continue around the room with minimal drop in amplitude. In fact in one second of listening time, the sound from one speaker will reflect around your room over 500 times.

It is important for you to get a real understanding of reflected sound vs. direct energy. Direct energy is the sound wave that comes directly from your speaker and passes by your ear. Reflected energy is everything else that you hear. If these reflections are not reduced in amplitude AND in time you brain will have difficulty telling which one is the direct sound and which one is the reflected sound. Localization cues will be destroyed and the result is an out of focus sound image.

To get a grasp on this, turn your speakers around 180 degrees so they face directly away from you and spend some time listening. Listen from your chair and from different places in the room. REALIZE that everything you are hearing is reflected sound and nothing your hearing is direct energy. In an ideal setup you would want to hear only the direct energy with none of the reflected energy. Think about that for awhile during your listening experiment.

The difference between good sounding stereo and bad sounding stereo is I figure at best 50% the room, or specifically how the reflected sound is handled, and 50% the quality of the gear you have.

While I'm thinking about it, and after 20 some years of wondering for sure, I have concluded without doubt that as far as gear is concerned the Source is the most important part followed by everything that follows it and in that order. The only thing more important than the source is the room you play it in.

Let's look at a conventional setup, as shown in figure 2.

The room shown in figure 2 contains a listening chair and the only the left speaker for simplicity. The speaker is shown in the color red. Since most localization cues for the human ear are higher in frequency, this simple diagram can be used to demonstrate the reflection points with the highest energy. You may remember that higher frequencies are more like a narrow beam, the higher the frequency the narrower the beam. Bass by contrast enclosed in a room with 4 walls is omni-directional.

For starts, concern yourself with the black lines and the numbered reflection points. The yellow lines will be discussed later. These black lines represent the center of the higher frequency sound beam. Every time sound hits a surface, such as a wall in your room, there is some sympathetic resonance in the wall itself as well as refraction. The black line in figure 2 only shows reflection. This means that even though reflection point #1 is located behind the listener, he or she will still be able to hear the result of that reflection which is resonance and refraction. Refraction would be sound that didn't perfectly follow the angle of the line, and instead randomly refracts back to other places. This effect was first talked about in the 80's when speaker manufactures realized that boxy grills and sharp corners on speakers were responsible for refraction that distracted from the imaging.

Reflection point #1 depending on the wall surface could effectively move midrange and higher frequencies closer to the listener. In other words, it could artificially drag parts of the soundstage forward.

Reflection point #2 is located on the rear wall behind the right speaker. It would be desirable to have it behind the left speaker if you had to have it at all. This particular point could have the effect of enlarging the size of images by stretching them horizontally and at the same time defocusing the primary image.

Reflection point #3 is also on the wrong side of the room causing further confusion in your perception of the original image.

Reflection point #4 is also on the wrong side of the room now behind the listener again, and even though reflections 5 ~7 are in the correct half of the room, they simply set the stage for the next half a dozen reflections to be on the wrong side of the room again.

You'll start to realize it's no wonder we've all spent so many maddening hours trying to get stuff to image better isn't it?

ALSO in figure 2 are some softer yellow lines that show what happens when you change the toe angle of your speaker by only a few degrees. If you start at the speaker and following the line you will see that point #1 has moved left be a couple feet. This would have the same effect as the original reflection point #1 but with the added illusion of better width, moving your image to the left slightly. The second, third, fourth, fifth, and even the 6th reflections that follow on the yellow line are now on the wrong side of the room.

It is easy to see if you study the possibilities for awhile, what is actually happening to your imaging and the shape and size of your soundstage by the major location changes of these reflection points with minor adjustments to your speakers. Also the room in figure one is a 13 x 15 foot room. I choose this shape because it's more likely to occur in your homes than a perfectly square room would be. Naturally, changing the dimensions of the room in Figure one drastically changes the locations of the reflection points, but you will find in most cases those first critical 5 or 6 points end up on the wrong side of the room.

Now, if you added the second speaker to Figure 2, and mirror image the points, you would have left channel information in both ears, as well as right channel information in both ears. Not an ideal situation at all. The result of this room effect is a projected mono image in the center of your speakers that shifts to the right when you move your head to the right and visa versa.

This is not real. And if the recording was mixed with the vocalist off center slightly, the effect will defocus the image more than if the recording was panned dead center. In this situation, which is one that 99% of all listeners are in, recording techniques will be colored to a degree that some will seem to image well and some just terrible, all depending on where the pan pots were set in relations to the reflection points in your listening room.

Adding absorption and diffusion to the wall surfaces at these critical points can reduce the problem to an acceptable level, but never eliminate it entirely. Nothing is truer than the statement; "You can't make a bad room sound good" and the reason it's so true is that "bad" rooms are locked into a particular performance by their dimensions which can't be changed. All the room treatment in the universe can only reduce the negative effects of the bad dimensions.

This really hit home as I went back and forth between the two setups. Let's look at the second setup in the same room.

The same 13 x 15 foot room with the diagonal setup is shown in Figure 3.

Notice in this set up even at the somewhat random placement I came up with for this drawing, the only points that are on the wrong side are points 4 and 5. And reflection point 5 considering where it is, isn't too critical. The lighter yellow lines show what happens when the speaker is toed in by a few degrees. Basically nothing really changes much. Dots shift rather than changing walls.

In practice I have noticed this arrangement to be far more forgiving as far as speaker toe angle, and much more flexible to actual speaker placement. This arrangement also has a much larger sweet spot. The fascinating thing here is the results. When compared to the conventional setup with all the room treatment diffusers and so on, I find this arrangement in the naked room to be actually better.

Before and after this setup, I used a variety of CD and LP recordings including several of my own that I recorded myself in my own studio of various guest musicians and jam sessions. In these recordings care was taken to properly mike the room, and quality gear was used. From these reference recordings I could now make a test of the Shifting effect I spoke of earlier knowing this time exactly how mixdowns contribute to the effect. The result was this:

In the conventional set up shown in figure 1., the effect was present even in my own recordings. In the diagonal setup shown in figure 3,. the effect was gone. I could move my head as much as 2 feet in either direction and have no shifting of the center image. Profound.

So, in short, I now have my listening room back. Before I had a width of 13 feet and a depth of 15 feet. Now in the same room I have a width of over 19 feet and a depth of over 19 feet, and it sounds like it too.

Taking it to a finer level would be fairly easy by purchasing a laser pen and fastening it to the top of your speaker and then taping mirrors to your walls to find your exact reflection point centers. This is where the most energy of each reflection is located. Once you have found a way to get as many points on the correct sides of the room respectively, then you can take action to treat the offending points. For example in Figure 3., the reflections points 4 and 5 are on the wrong side of the room. They could be treated. Keep in mind that eliminating those points would eliminate all the successive points and reduce ambiance. This could be a good or bad trade off depending on the actual locations of the points. But nonetheless it is the approach one would take.

It's also interesting to notice in this model how the corners become your friend in the way they triangulate the points. Not unlike a pool ball. In a conventional setup such as shown in figure 1., the corners are NOT your friends and ironically for the very same reason.

Bass issues will also be a little different in this scenario when compared to a conventional speaker and listener placement, but all in all you should still trap the bass. Since bass does not triangulate around the room in tight enough patterns to create reflection points this angled setup will not do much to correct room boom issues.

So in conclusion, the results of the diagonal setup were superior to the conventional setup, the irony is that this was with no room treatment in the diagonal setup and both with and without over 2100 lbs. of diffusion in the conventional setup.

I would say that if you're serious enough to have a dedicated room for JUST your stereo, you can have a better room than our reference room was at one time with all the treatment., and do it for nothing. If you HAVE to have a home theater using a big screen TV and stereo together in the same room, then this diagonal setup will largely reduce some of the imaging problems provided you locate the TV as far back in the corner as possible.

Figure 4 shows a picture of the same end of the room as you saw earlier above, completely rebuilt.

paper023

HOW TO SET UP A ROOM WITHOUT FANCY TREATMENTS by Steve Deckert April 2000

One of the things I find myself discussing with people on the phone quite frequently is the relationship between speed and good sound. More specifically how the speed of components combine to effect either a nasty or musical sounding system. BTW, price has nothing to do with it.

In fact, you can spend 20 or 30 grand on gear and have a horrible sounding stereo, and in contrast your neighbor may have some old junk that wouldn't total $1500. and sounds pretty good on almost everything. Always musical. Now I've seen this happen hundreds of times, and the reason I'm writing this is to help you to keep it from happening to yourself, if it's not already.

Every component can be subjectively judged on the criteria of speed, among other things. Speed can be tied to transient response, dynamic range, and clarity. It is largely a function of the power supply. Assuming that the circuit or speaker has low distortion and low coloration it will have good clarity, but the speed is determined by the design itself.

For example, in electronics, speed is largely a function of capacitor discharge rates, voltage swings and part counts. In speakers, speed is largely a function of efficiency, mass, and flux density.

You could have a speaker that is fast like a Lowther or some low mass paper cone speaker with a large high energy magnet (usually an efficiency of 100dB +) or you could have a speaker that is slow like a 12 inch woofer with high mass and a normal or low efficiency of say 86dB.

Speakers are the easiest component to relate to speed because the largest factor is always the moving mass. In the 12 inch woofer we may have a moving mass of 85 grams. In the Lowther or similar speaker we may have a moving mass of (I'd guess) 11 grams. Without understanding anything else about the dozens of variables that affect this, simple physics dictates that the lighter something is, the faster it can change directions and move.

Electronics are far more complex from a speed standpoint, but equally as important. A simple example of how the speed of electronics can affect the end result consider the following two examples:

A) If your speakers are fast, and your amplifier is fast, and your preamp is fast, you would find that the average $500.00 CD player becomes unlistable. Reason being the electronics and speakers can now reveal the shortcomings of the source. Result: Fatiguing and non musical

B) In the same system, a slow preamp is installed in place of the fast one. Now the grainy top end is gone, the digital sound seems smoother more analogue and the end result is pleasing non-fatiguing sound. The reason being the preamp has masked the shortcomings of the source.

Masking, or altering the sound is often the side effect of complex circuits that use lots of parts. The less parts in the signal path, the faster the circuit typically becomes. Other factors that influence the speed of audio circuit are the speed of the power supply and coupling caps.

Now suppose in the examples above that the source was a world class turntable and cartridge instead of a $500.00 CD player. In that situation both A and B would be musical, however A would sound far superior with greater dynamics, loads more detail, and far better clarity.

A good stereo system is an artful balance of speed between components. A good component is an artful balance of circuit design and power supply speed. Going a little deeper, the speed of each coupling cap and each gain stage should be artfully balanced to that the component as a whole is musical. A fast circuit with a low cost power supply would sound spongy with high distortion and a lower overall speed. This imbalance is called stress. Some components. have stress built in, stay away from those.

How does this all trickle down into usable advise you might wonder? First you need to understand that the quality factor of your component hierarchy should always ideally be as follows: Source, Preamp, Amp, Speakers. That means your source is 400% more important than your speakers.

Since the advent of CD's, for the masses music quality went up, but for the audiophiles, music quality went down. CD players still do not compare to turntables, and likely never will. It would be a safe thing to assume that most audiophiles are using CD players as their source. Given that, the source is most likely the weakest link in the vast majority of high end systems. The better the performance of the system, the worse the sound as it reveals deeper and deeper the qualities of the source.

Now, I've found that if you have a very high end system (fast) it takes around $5000.00 at the time of this article to put together a musical front end for CD's. Most of us don't have the budget for that and the majority are using mid-fi CD players and or entry level DACs and transports. Ironically most spend lots on a DAC and little or nothing on a transport when the transports usually make far more difference. In any case, the majority of people who feel they're systems are approaching high end, have an inferior source and constantly fight with an overall lack of musicality.

Here are the symptoms of a speed disorder:

Fatiguing to listen to over time
Sound good sometimes and terrible the next for no reason
Sound quality is very CD dependent. Some CD's can't be listened to.
Grainy top end, with traces of glare
Occasionally shouts on certain passages
Irritates your wife
Constant fighting with speaker placement, and cables.
Sound like you?

You have two choices. Step up to the plate and buy yourself a REAL source for the real big bucks, or slow something down until nothing sounds great but nothing sounds bad either, the result being a musical system that no longer distracts you with the above symptoms.

Slowing things down from a component standpoint really means masking things. This can be done with lower quality cables, such as entry level audiophile type cables between components. This can also be done with speakers by going to higher mass lower efficiency, or just plain smoother better sounding speakers that have a warmer exaggerated bass and or rolled treble. It can also be done in the amplifier(s) or preamp by finding models that are less revealing.

It can be a hard pill to swallow sometimes but if you want some insurance or a safety factor that your system will be musical and enjoyable to listen to, odds will be in your favor if you shop for new or used gear that sings well together. Odds will be against you if you automatically go for the most expensive matching gear you can afford. This is in fact one of many audio paradoxes and is why a guy who found an old Dynaco ST70 at a garage sale and a pair of old Advents usually has better sound than his neighbor who owns the big name high dollar amps and speakers that were supposed to be the shit.

Unfortunately since how good something sounds is subjective and the mind is a powerful thing, those who've spent big bucks on gear and gotten poor results usually don't know it. This is because any time you spend a painful amount of money on audio gear and take it home the sudden change from what you had fools you into automatically thinking its better, followed by the need to justify the money you've spent which always has the effect of biasing your judgment.

And of course during this trial and error time of trying new things that are on the expensive side, you will find it usually doesn't sound as good as you'd hoped so you let it burn in for weeks hoping it will get better. And while things do improve once they're burned in, you have also grown more accustomed to it, and more tolerant of it.

Speaking of hard pills to swallow, I have seen over the years so many things sound good that shouldn't, and at least 200 times as many things that should sound great sound terrible.

I have found the reasons for this is the musically or balance of speed within the system and the acoustics of the room its played in. A 50/50 split down the middle. A $500 stereo can sound better in a good room than a $5000 stereo in a bad room. Over half of all audiophiles (and in reality it probably more like 80%) have poor rooms. Add to that overpriced gear that's too fast for the quality of their source and you have the very fuel that feeds the industry., i.e.. Frustration and the never ending search for a musical system which grows in intensity in direct proportion to the amount of money you've spent.

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MUSICALITY IS A BALANCE OF SPEED

by Steve Deckert
May 2000

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PENTODES, TRIODES & FAKE TRIODES

by Steve Deckert
June 2000

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PENTODES, TRIODES & 'FAKE' TRIODES by Steve Deckert June 2000

Whether you're listening at ten watts or a hundred, the most dynamic range occurs within the first watt of playback. This equates to around 30 dB of dynamic range in that initial watt. Adding a second watt increases the range by another 3 dB, and from there, the power must double for each additional 3 dB increase. In audio, power yields diminishing returns.

In a typical small apartment, the noise floor during the day is around 45 dB. The softest tone the human ear can detect at 1,000 Hz is about 5 dB. For a tone at 30 Hz to be just audible, it must be at least 60 dB.

In a 600,000-cubic-foot concert hall, a full symphony orchestra can reach a sound pressure level (SPL) of 120 dB at the listener's ear. The power required to achieve this level is immense. However, if you transpose this to a 4,800-cubic-foot listening room, the power needed to reach the same SPL would be much less. Assuming the listener is seated about 8 feet from the speakers, reaching an SPL of 120 dB would require approximately 40 acoustical watts. Some modern speakers have efficiencies as low as 0.1 percent, while the most efficient ones approach 40 percent. A 0.1 percent efficient speaker would require 400 times more power than a 40 percent efficient one. In fact, to achieve 120 dB at 8 feet, the 0.1 percent speaker would need 40,000 watts, whereas the 40 percent efficient speaker would only need 100 watts.

You might think there's a significant difference between a 2-watt Zen triode amplifier and a 120-watt solid-state amplifier, but in reality, it's only a 20 dB difference. On a 100 dB efficient speaker, 2 watts produce 103 dB, while 128 watts from the bigger amp produce 121 dB. If you set the volume for a peak level of 100 dB (which is much louder than the average home listening level), there’s no difference between the 2-watt amp and the 120-watt, 250-watt, or even 40,000-watt amps. If you want that extra 20 dB of dynamic range, lower the noise floor and listen at night. This will sound far superior to the same dynamic window during the day, even with a larger amp, because there's 20 dB less ambient noise polluting what you hear.

For what it's worth.

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DYNAMIC RANGE by Steve Deckert November 2001

This original article was written in February 2002, after a customer sent in an amplifier for upgrades. The amplifier was covered with foil stickers and writing, both of which were supposedly magical. The stickers and pen had been quantum-treated, and the idea was that writing the word "yes" with the magic pen on anything would make it sound better. To test this, you could write "no," and it would then sound worse.

Never mind that the person who purchased these tweaks spent enough money to buy better cables or tubes—things that could be heard by everyone, not just the purchaser.

In one of my weaker moments, I called out the manufacturer, who had apparently gone to AutoZone for the foil pinstriping and Office Depot for the Sharpie markers. This manufacturer then sold these items for hundreds of dollars by creating a marketing gimmick.

I once received one of my Zen amplifiers back for repair. It had been treated with both the "PWB Red 'X' Co-ordinate Pen" and "Rainbow Foil." The amplifier now looked similar to a heavily decorated object.

See figure one. The caption was something to the effect that this baby has been treated with the Red 'X' Coordinate Pen and now it will never get sick.

While this is an extreme example, quantum treatments have become a big thing for high-end snake oil salesmen or anyone wanting that 1000% markup to keep their business afloat. On a lesser scale are the things we do to ourselves, like listening to fuses in our gear, flipping them around, and claiming they are directional because we think we can hear a difference.

How good your system sounds is determined by the weakest link in the audio chain, and unfortunately, that includes both your room and your ears. When we talk about your ears—provided they work and aren’t clogged—we’re really talking about your brain and how it interprets sound and spatial cues from the stereo. This particular weak link can be the hardest to track down since it changes frequently. This is why placebos are so powerful in the world of audio gear.

Do things like lifting your speaker wires off the carpet make a difference? Sure. But can you actually hear it? That’s the big question, isn’t it? If you believe you can hear it, especially after letting things settle in for a few hours or days, you’ll likely enjoy your system more. However, if you’re uncertain, you can always set up a double-blind listening test to find out for sure.

Does a power cord that costs $20,000 sound better than one that costs $2,000? Do either of them sound better than a $200 cord? Once again, if you want to know the truth, double-blind testing will give you a clear answer. Over the years, the industry has responded with products that, through the power of placebo pricing, cause people to waste their money.

You can imagine the pressure on someone who just spent thousands of dollars on a power cord to justify that expense. This is the most powerful audio placebo there is. It’s why we have an industry full of grossly overpriced equipment.

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THE POWER OF SUGGESTION by Steve Deckert Feb 2002

$I've often seen comments dismissing the accuracy and importance of "holographic" imaging in stereo playback. As always, I have a strong opinion on the matter. The truth is, there's no such thing as "accuracy" when it comes to good sound. Things that are accurate on paper often sound terrible, while those that sound great in subjective listening tests often perform poorly in measurements. My advice? Leave the accuracy debate out of this. Is holographic imaging important? Absolutely. It serves as a valuable tool for evaluating the true finesse of any stereo system. The thrill of high-end audio lies in its ability to transcend mere frequency balance and create a space from which sound seems to originate—a space defined by its width, depth, and height, and by the illusions that unfold within it. Light (eyes) and sound (ears) are more similar than you might think. If you wanted to technically define the process that creates these illusions in a three-dimensional sound space, you could look at the illuminator equations used in ray tracing. These equations define and map a four-dimensional space to create a three-dimensional image on a two-dimensional plane. A simplified version of an extended (partial) illumination equation is as follows: N __ \ n I = Ia Ka + / IL(Kd cos(theta) + Ks cos (alpha)) + Ks Ir + Kt It. ~~ L=1 The values used in this equation are: Ia [RGB]: Global ambient light IL [RGB]: Light contributed by light L Ir [RGB]: Light contributed by reflection It [RGB]: Light contributed by transmission (refraction) Ka [RGB]: Object ambient color Kd [RGB]: Object diffuse color Ks [RGB]: Object reflection color Kt [RGB]: Object transparent color n [Real]: Phong specular factor N [Integer]: Number of light sources If you substitute the word "sound" for "light" and "harmonic" for "color," you're essentially looking at one of the fundamental formulas for imaging. So, why is holographic imaging important? It's crucial because it effectively squares the amount of information perceived in the recording. When I evaluate the fidelity of an amplifier, I find that the true indicators separating a great amp from a merely good one are as follows: Its ability to handle sounds that move within the soundstage. Can a sound move from the right rear to the left front in a linear path? Can it move in complex arcs or circles, gracefully transitioning between vertical and horizontal? Imagine orbs of shimmering sound that hover in the sound space like UFOs. Visualize their flight paths as you listen. How many can your system accommodate simultaneously without losing focus? This is the quickest way to discern which amp is better, assuming all else—frequency balance and general signatures—are equal. For example, consider two Zen amp prototypes using different coupling capacitors with nearly identical signatures. Casually set up in an average listening room, both sound identical in every way. However, when evaluated in a system that excels at holographic imaging, the assessment of moving targets within the sound space will reveal that one amp has a speed issue with the orbs. They skate through certain quadrants of the sound space faster than in the surrounding quadrants, distorting their rhythm or pace. Creating an amplifier with a good (flat) frequency balance is something anyone can do with a bit of effort. Most people who dismiss holographic imaging have likely never truly experienced it.$