A U D I O... P A P E R


Feb 2004 by Steve Deckert

I write this article for two purposes.  Firstly because of recent personal experiences and second because I can duplicate the experiences with a new product that would well represent my work and help further our companies good name.

Somehow for the majority of my years as an audio enthusiast I have never owned what I would call a serious audiophile headphone setup.  So it goes without saying that I also have never really experienced one.  That is not to say I havenít spent plenty of time listening to headphones.  In my studio we record live every Thursday and have for close to 10 years.  I listen to headphones on a regular basis in the studio.  

Rather spontaneously one day I called Sowter to chat about the transformers they make for our signature phono stage and before getting off the phone I caught myself asking if they had any decent headphone transformers.  A few days later I had a pair on my bench.  The timing was perfect as I was really in the mood to do something different that day.  I had just completed building 6 of our Sony SACD players and just couldnít do another one.

I wonít get into the specifics on the design in this article, but I will say that Iíve been researching headphone amps for the past 4 years because so many customers have asked for one.  By now I had a very clear idea of how I wanted to proceed so when the transformers showed up the layout and chassis considerations had already been resolved.  I had my first working unit by the end of the day.

The following day was spent voicing it.  I didnít get very far before I realized I was going to have to get some better headphones.  Compared to my studio I was getting some real special results that I guess I wasnít expecting.  After returning an hour later with a pair of BeyerDynamic 250 ohm headphones I was again surprised at how much easier the voicing process went.  Within 2 days I had explored every possibility and settled on the best circuit.

Okay now that we have that out of the way, this is where it gets fascinating.  All the epiphanies that hit you in rapid succession Ė things I feel compelled to share because I canít help but think perhaps most of our customers and audiophiles in general have overlooked headphones as a serious alternative to setting up a listening room. Personally I never much cared for them because I like the illusion of a 3D image in front of me with the added fascination of watching two large speakers disappear in my room.

As a designer of loudspeakers and amplifiers you could say my life revolves around the success of that illusion.  I have always looked at the empty space between a pair of loudspeakers as a three dimensional canvas where I work feverishly to create deep lucid images of sound.  Iíve just never seriously considered working without that canvas or in any other medium until the last few years. As a result of gaining a deeper understanding of good sound Iíve become increasingly aware of the other elements of good sound that have nothing to do with conventional imaging.

It used to really bug me in my younger years when I would hear someoneís stereo and it didnít image.  Sometimes it would still sound good but without the illusion I just wasnít sucked into the music.  The biggest explanation for this turns out to be not the lack of imaging but overall fidelity in general.  Since listening to Zen Triode amplifiers for the past 10 years on so many different speakers I canít count them anymore, Iíve had many opportunities to hear them set up in situations where there was no real sound stage, yet the playback was so good it just didnít matter anymore.

Just look how hard it is to get perfect sound out of your stereo.  The journey starts with lots of money spent on gear and room treatments and usually a variety of loudspeakers until you finally find something that starts happening for you.  Then you discover really good gear that may or may not cost a lot of money but makes you realize that your previous system actually sucked.  For some this process is an endless cycle.  Each time you replace something in your system that makes your previous component suddenly sound like crap is a form of ascension to a higher awareness of what good sound is.  You wonder with each step where the ladder actually stops. With each successful step you canít imagine how it could get any better and thatís the thrill of this hobby because it usually can!

Good sound is a delicate balance that when knocked out of balance creates an underlying chaos that hides itís true beauty.   Most people including audiophiles have statistically never heard itís true beauty because of one or more weak links in the component chain.  The power from the wall outlet.  The power cord.  The connection at either end of the cord.  The source, the cables, the preamp, the cables, the amps, the cables, the speakers and all the associated connections.  Then there is the room, speaker quality, speaker placement, reflections, type and application of room treatments, the listening chair, itís location. Etc. etc. etc.  All of these variables without exception make up the complete chain of components in your stereo.  The fidelity of your stereo can never exceed the single weakest link in this audio chain. The delicate balance is exactly that.  Ask me which single item is the most important and you arenít understanding the concept of delicate balance.

I will point out that you could divide the chain into two parts, gear and room.  They would be chains of equal length and merit.  Most people focus all their resources on the first half of the chain while remaining in denial that the second half of the chain even exists.  For this reason alone I can claim with all the confidence in the world that headphones even without the natural depth of image you get with loudspeakers are going to sound better.  But thatís just the largest of many reasons why they do.

Loudspeakers are high in several forms of distortion compared to every other component in your stereo system.  A problem that increases with volume and aggravated by standing waves in the room that further alter the frequency balance by as much as 20 dB.  Headphones do not have either one of these problems.

Loudspeakers have limited frequency response.  Low bass is often determined by the longest distance between two opposing corners in your room because of the standing waves in the room.  The average listening room starts having serious problems with bass peaks and or holes starting around 80 Hz.  Itís not uncommon for a room to kill the bass below 35Hz.  Headphones do not have these problems.  Response is typically down well below 20Hz.

The bulk of all dynamics in music as well as the majority of the magic itself lives in the first watt.  The second watt adds only 3 dB with exponentially diminishing results from there.  To achieve bliss, a Zen amp for example, driving an efficient speaker will captivate a listener with no more than 2 very serious watts.  But no matter it seems how efficient your speakers are the sound is always better at night.  The reason for this is because the ambient noise floor in your listening room drops significantly at night.  It may drop as much as 20dB.  That means that music played back at night adjusted to the same level it was played during the day will have 20 dB of added dynamics, detail, with silence between the notes being perfectly black.  Headphones, the closed back designs, offer typically around 18 dB of ambient noise isolation.  Thatís enough to turn day into night, and turn night into heaven.

And while we're on the subject of dynamics and efficiency - 2 watts on a Zen amp is plenty loud on the right speakers but A) how many people use the right speakers with one and B) can you ever have enough power for those moments when you just want to crank it Ė even with the right speakers?   At some point itís bound to get ugly as the gear begins to distort aggravated by the room.  Headphones do not have this problem.  No distortion, and no apparent limit to volume.   For example the BeyerDynamics I am using are around 96 dB Ė same as our top of the line High Definition Tower speakers using the Fostex drivers.  My new headphone amp has a max clean output into these phones of about 300 miliwatts.  Thatís three times what the phones will handle.  You might think that with only 100 miliwatts that a 96dB system wouldnít get any louder then a Zen amp on our reference speakers but donít forget in the case of the headphones the speaker diaphragm is located about ľ inch away from your ear and is automatically 18 dB louder from the ambient noise rejection.  

I have never been able to get the volume control past ľ on my headphone amp and can safely say it sounds about a 100 times louder than Iíd ever want to listen to it. So in short there are no limitations to how loud you listen and BIG BIG BONUS Ė noone else will hear it Ė even in the same room.

Resolution Ė for this I use my Acoustats with custom servo charged tube amps driving the panels directly with no crossovers, 20Hz Ė 20kHz  response with no phase shift. Arguably in the top 1% of the best loudspeakers in the world.  This system is a benchmark for resolution but even as good as it is the headphones are still better.  To illustrate the kind of detail extraction that is possible to hear with good headphones compared to good loudspeakers do the following experiment: If you have a watch that ticks on your wrist or a clock in your house wait until night time and listen to it from a distance of 1 meter away.  What you hear is the max resolution you can hear at that distance.  Now put the watch or clock up against your ear.  The 10 fold increase in information you hear is similar to the difference between good headphones and good loudspeakers.

Going back to the weakest link concept, it stands to reason that a VERY good headphone amplifier is imperative to make good headphones sound good.  Now, maybe I got lucky and invented the worlds best sounding headphone amp but I am sure there would be many that would be good enough to get you as wound up as I am about it. One of the biggest surprises is that Iím just using one of our modified CD players with this headphone amp and comparing the results against my reference vinyl rig and enjoying it with similar enthusiasm!

I canít help but think that especially for someone just starting out in the hobby that this headphone amp and a pair of decent headphones the total of which is less than $1000.00 would be an intelligent alternative to trying to set up a listening room.  And I suppose that if a person was to start out this way, and later wanted to set up a listening room with similar sounding gear he or she would have a reference which could never be topped throughout the process.  That would undoubtedly effect their buying decisions because by comparison most everything they try would sound inferior. That would really help a person choose the right stuff the first time.



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