Asheville Home Theater and Audio presents Paul McGowan – PS Audio, Intl.

There’s a lot of controversy in yesterday’s post and I actually got some hate mail.  Wow, first time for everything.  I am not going to defend the post or my thoughts since it’s clear a number of people misunderstood my intent and thought process, yet an equal number got it.  I think those are good results.

As an adjunct to yesterday’s post NPR (our public radio in the United States) ran a terrific article on teaching democracy to students through jazz.  Jazz is focused on improvisation and to create music on the fly requires a group of people to get together and agree.  What a marvelous idea to integrate jazz into the classroom.  You can hear that broadcast by clicking here.

I would like to expand on yesterday’s core subject, however, the art of design.  Let me just suggest that there are many ways to design equipment, just as there are many ways to cook food.  Designers can follow tried and true recipes and prepare some wonderful sounding equipment, just as chef’s can do the same.  But rarely do designers or chefs standout as stellar examples of innovative creations by following recipes.

No, only those designers and chefs that have the courage to step outside their comfort zones and get away from the tried and true stand out.

There’s art and skill in following a recipe of design or food and creating a successful end result.

But for those adventurous enough to step outside their comfort zones and try something new, especially in the art of reproducing music, the potential rewards for their customers are huge.

Recipes are safe, creative art can be scary.

Asheville Home Theater and Audio presents Paul McGowan – PS Audio, Intl.

Most technology based categories of products do not tolerate or encourage art and individuality.  Rather, they reward sameness and polish of existing art.  Take computers, for example.  The art in computers can be found in their packaging and peripherals but rarely in their performance.  Yes we can have faster, slicker, more efficient but they all better do exactly the same thing or they wouldn’t make it past first base.  Let’s put this observation in musical terms.

Most technological products resemble classical music more than jazz.  In classical music perfection to the original score is highly prized.  The art in classical music comes not from playing different notes than the original score, no, that is strictly verboten, but rather from slight variations from perfect.  Jazz, on the other hand, rewards different notes and recoils at sameness.  Jazz rewards mistakes in playing the instrument as long as those mistakes are in service of new emotion, new art, coaxed out of the artist’s soul.  Hit a wrong note in classical and people wince; perfection first and once achieved, let the art begin.  Hit a wrong note in jazz and we tolerate waiting for the soul to emerge; to heck with the notes.

High-end audio design is more like jazz than classical.  I like that.  It’s one of the few technologically based categories that rewards art over perfection.  The mavericks in this industry are some of the most creative and artful people I know.  More like musicians than engineers, high-end audio designers have soul.

Sure, as designers we want perfection, but not at the expense of art.

Asheville Home Theater and Audio presents Paul McGowan – PS Audio, Intl.

ne of my readers wrote this in response to my post The gift of music.

“My daughter is 16 and part of the MP3 generation.  I am trying, and gave her 16 CDs for Christmas, all of her favorite music.  She promptly loaded them on to her phone.  Yet when I play them on my system she is captivated, but not enough to overcome the convenience of having the music on her phone.  I fear that we are fighting to losing rear-guard action, but I will go down fighting.”

Bravo and don’t give up.  It is not a losing rear-guard action at all.  16 year olds are in a hurry.  16 year olds don’t have time for anything other than figuring out where they fit in.  But they are hungry for what we give them.  They will need it later.  By exposing the daughter to new music and captivating her interests in better sound, if only for a moment, plants a seed that will blossom in its time.

Like Johnny Appleseed, we Audiophiles need to plant as many seeds as we can and then nurture those seeds if possible.  But even without nurturing, planted seeds will many times grow into wonderful new trees.

Take heart.  When the daughter is in her thirties and gets another opportunity to appreciate the better performance of a great system it will be as if a lightbulb turned on in her head.

Planting a new seed is the only way a tree grows.  But it takes patience, love and nurturing.  You’re giving her both.

Asheville Home Theater and Audio presents Paul McGowan – PS Audio, Intl.

Feeding and caring for our biases

Over on the Community Forums one of our posters suggested they had previously owned several class D amplifiers and found them to sound thin, cold and unengaging.   “Why would anyone bother producing such an amplifier?”  On the face of it it’s a good question.

Problem is, the type of amplifier topology has little to do with how it sounds.  Yeah, I know, that doesn’t ring true does it?  I mean, all class A amps sound a certain way, just as all tubes amps, all class A/B, all Class D amps?  Doesn’t that fit your expectations and biases?  But then you hear an amplifier that sounds open, gorgeous, musical in every way.  You wonder what magical properties it must have to sound like this?  Let’s just say for this post it doesn’t matter.

It doesn’t matter because it’s near impossible to generalize performance from a specific topology.  It’s hard because in large part that sound is more dependent on how the designer managed the design rather than the topology itself.  Everything from the power supplies to the input stages, to the chassis parts, isolation, wiring, connectors etc.  The same is true for loudspeakers, turntables, cartridges, etc.

As humans we compartmentalize things.  Life’s much easier if we can place our biases, opinions and conclusions in small compartments that serve us well.  We read a review or group of reviews and compartmentalize the reviewer’s conclusions into easy to access data.  We hear a set of speakers and form an opinion that now extends to any speaker similar in construction.  We like the sound of moving coil cartridges so we never consider a moving magnet.  Air bearing turntables sound best, direct drive motors are to be shunned, switching power supplies all sound a certain way.

I know it’s hard to release some of our cherished biases but if you can, it’ll help in your quest for what really matters, how it sounds.

Asheville Home Theater presents Paul McGowan – PS Audio, Intl.

The gift of music

Yesterday was Christmas and as we opened our presents it occurred to me that few of us give music anymore.  At least my family doesn’t give music as a gift.

Years ago it was commonplace to get a new album, and new CD for a gift.  Perhaps it’s only me, but I see far less of this and think it’s a shame.  What greater gift could one give?

I think next year I am going to make a point of giving music as a gift to family and friends.  New music.  Curated music.  Music that I personally selected that I want to share.  That’d be a great present.

Perhaps a gift idea for you?

Asheville Home Theater presents Paul McGowan – PS Audio, Intl.

… that we don’t notice things until we hear something different?  That we don’t notice there’s no body to a cymbal until we hear one that has it?  Or we don’t notice the signer’s voice is anything but natural until we’re presented with the same voice in a live setting?

Our ear/brains have amazing abilities to adapt to our surroundings and allow us to comprehend sounds and their sources even if they aren’t true to those sources.

It is only when we hear something more natural that we instantly recognize the deficiencies and then find it hard to imagine how we ever bought into the first sound as being real.

I just had such a moment recently listening to music I know well.  A new piece of gear comes in and that same music revealed much that was wrong with what I was listening to and apparently had adjusted myself to the reference.  As soon as you hear something “more right” you reject the original and can’t even imagine how you lived with it as being accurate.

Our references are not set in stone.  Not even those that we compare to the “real deal” which is live music, because even live is dependent on your environment, mood and circumstances.

In truth, the Absolute Reference is a myth.  But a nice one.

Asheville Home Theater presents Paul McGowan – PS Audio, Intl.

I just finished uploading the last in our series on Building a Music Room.  This edition, the 7th and final in our series, can be viewed on Youtube by going here.

I’ll share something with you that truly has me baffled.  If you go to our Youtube channel you can see that the 6th video in our series has garnered nearly 53,000 views while the others all average about 7,000.  While I agree that the 6th video is the most interesting because it shows the setup of the giant IRS in our music room, I surely don’t understand how or why so many people viewed it.  Don’t get me wrong, I am delighted.  I am just baffled.

In the latest video we cover how we solved the bass problem in the room.  You may remember from the other videos that we had a pretty serious 25Hz bass bump in Music Room One.  We experimented with installing the Helmholtz Resonators in each corner to reduce the bump but failed to get more than a small reduction.  So what did we do?  As I explain in the video, we moved the listening position to be smack dab in the middle of a bass null.  We then moved the speaker set to match the listening position.

This is something any one of you can do if you have a low bass issue in your room (either too little or too much).

Typically when we setup a loudspeaker pair we position the speakers where they work best in a given room.  We then place the listening position where we get the best imaging and tonal balance for the speaker position.  But many times you must do the opposite if you have low bass problems.  Having said that it’s also true that most of you don’t have these issues because you probably don’t have low bass unless you have installed a subwoofer.  But for those with a sub that produces true low bass, you can follow these few steps to fix room problems.

The first step is to determine where the problem frequencies are.  This is important because if the problem bass frequencies are low enough (20Hz to 30Hz) moving the subwoofer around isn’t going to do much.  In this case, you’ll have to move yourself around to find the point in the room where the build up suits your needs.  If the bass issues are higher up the frequency ladder, moving the subwoofer itself is effective.

If you don’t have the advantage of a tone generator, you can use music to help you out.   For this I choose something with a pipe organ to help me figure out the frequency I am concerned with.  My favorite is Reference Recordings Requiem.  Rutter’s Requiem has some extraordinary low bass.  Bass low enough that most people don’t even know it’s there because most people have inadequate bass.  It’s also interesting to me those same people think they have good bass.  Track 9 is perfect for this and the low notes of the organ should match the level of the other instruments and sound natural in the room.  It’s pretty powerful so don’t be afraid if it’s an eye opener when it plays, but you need to achieve proper balance with the singers and the orchestra.  Of course the subwoofer has level and contour filter controls and you adjust these first.

There comes a moment when the subwoofer adjustments, either though the sub’s controls or placement in the room, gets one part of the spectrum right (hopefully the upper bass above 30Hz) but not the other.  From your listening position you hear too much of the low organ notes and turning the sub level down loses the rich full body of the midbass.  This is the point where an experienced setup person resets the sub level back up for best midbass integration and begins walking the room from front to back listening for the low bass nodes.  As I explain in the video, bass frequencies tend to bunch up in nodes through a room.  As you walk from front to back the bass level changes a lot.  This is where you can find just the right spot for low bass and that is where you set your listening chair.

Now, all that’s left to do is position the main speakers such that you maintain proper imaging and tonal balance based on the new listening position.

I know this is short and sweet and we could probably go on for hours, but without a proper setup disc it’s the best I can do in a written piece.

Asheville Home Theater presents Paul McGowan – PS Audio, Intl.

Reader Ed Houck reminds me of one of the best methods for bass setup.  It’s nearly foolproof and works not only for bass and subwoofers, but with full range loudspeakers as well.

I certainly couldn’t use this with the IRS in Music Room One because of their size, but if your loudspeakers are movable, try this great tip for setup.  Might make a wonderful weekend project.

It’s called the reverse placement method.  As an overview, you put the speaker in the listening position and then walk around the area you eventually want the speakers placed to find the optimal spot.

  • Place the sub (or full range loudspeaker) in the actual area you would like to sit, not in the positions where you want them ultimately placed.
  • Walk around the room with a roll of masking tape in the areas you’d like to place the speakers.
  • Listen for the best balance of mid bass and deep bass.
  • Mark that spot with a small piece of tape.
  • Continue doing this with as many spots as seem to present excellent sound. .
  • Once you have a number of options, simply place the sub or full range speaker into the place or places that offer the most reasonable WAF (wife acceptance factor).

If you have the luxury of a second sub, the same method can be used to get better bass in the areas of bass suck-out:

  • Locate the area of bass suck out
  • Place the sub in that spot
  • Walk around the room listening for areas where bass quality is high
  • Mark those spots with tape
  • Choose the spot you like best and place the sub there
  • If you have 3 or 4 subs you can continue to do this for a very uniform bass regardless of listening postion
  • Simple, quick, effective, and nearly foolproof.

Asheville Home Theater presents Paul McGowan – PS Audio, Intl.

I have often thought of my life as one lived by different people.  I feel distinctly different than when I was a boy, a teenager and a young man. Different enough that I seem almost like different people.  And one of those different people used to be far more impatient than the me of today.  So much more impatient that whenever I came into our engineering offices with a look of excitement, the engineers would flee for their sanity.  I would routinely yank hard at the rudder, stopping one project to start another.  While not entirely cured of this tendency, I would have to say I am much better than days gone by.

I have learned that I have to stand in line and wait my turn.  Such is the case with the new power amplifier we are designing.  I have been standing in line waiting to test out the latest front end.  I have now moved up to first in line and I thought I’d give you a sneak peek at what’s under the covers.

For those of you who have followed my Posts on a regular basis you may remember I delayed the launch of the PerfectWave Power Amplifier project, scheduled for release this month, because I was unhappy with the sound.  The high frequency part of the sound, to be specific.  The highs just weren’t there.  Sure it measured perfect, but sonically the amplifier sounded dull and lifeless on the top end.

My suspicion of why this happened centers around the input stage of this power amplifier, which is broken into two sections: the input stage and the output stage.  The original input stage was designed around a combination of bipolar and JFET devices in a classic discrete fully balanced amplifier topology.  There were lots of devices in the parallel amplification stages, minimal feedback, high output bipolar current buffers, high input impedance JFET buffers.  It’s a derivation of circuitry we’ve used for years and has served us well.

But the sophistication of the Hypex output stages are such that I am guessing they are revealing some of the closed in nature of this type of input stage more than I would like.  That closed in nature goes hand-in-hand with the amount of feedback in the stage and the way it’s implemented.

I know, I can see some of my readers eyebrows raising at about the same rate the hair on the back of their necks is shooting up reading that.  But I can tell you that as the level of feedback goes down, the degree of openness goes up.  In fact, there seems to be a direct 1:1 relationship when auditioned as a straight preamplifier.

So, you might ask, why not simply remove all the feedback and get on with it?  Well, in the end that’s what I’ve done but it was not without a great deal of agony as a designer because feedback provides a number of benefits that have to be made up some other way if you’re going to get the results you need.

I’ll explain what I did on the input stage tomorrow.  My fingers are crossed that perhaps by this weekend I’ll be auditioning the new amp.

It’s hard standing in line just to roll the dice.

Asheville Home Theater presents Paul McGowan – PS Audio, Intl.

We got close.  Really close.  The technician finished stuffing the new input stage, our chief engineer Bob Stadtherr brought it up and tested it, he and I spent a fun afternoon tweaking the square wave response and then 5pm rolled around.  5pm Friday December 21st.  The last day of work for a week for many folks at PS Audio.  Now I have to wait another week till the holidays are over before we connect the input stage of the amp to the amp module and listen to it.  I too am heading out this morning to spend a week with my family.  I am bummed about having to wait a week and impatient with the holidays getting in the way of listening to my new amp.  Where’s my lump of coal?

In the meantime let me tell you about tweaking the square wave response and a little more about this stage.  Round about 4pm Terri walked into the lab where Bob and I were huddled around the scope stroking ourselves over the beauty of the square wave of the new amplifier input.  We beamed with pride.  ”Check that out!”  Said I to Terri.

You know that look people give you when they think you’ve slipped a cog?

“Seriously?  Really?  You two nerds are admiring that thing on the scope and want to know what I think?”  No, we probably didn’t want to know what Terri thought.  Bless her heart.

There’s nothing like a good square wave response on an input stage.  I know this sounds funny because we don’t listen to square waves, but in fact square waves tell us a great deal about how a circuit is going to sound.  Not everything, mind you, but a lot.

A square wave is a collection of sine waves.  There’s a fundamental sine wave, the main one at the frequency you set, and then declining higher frequency sine waves that fill in the edges.  Over the years, as a designer, you look at a lot of these to see how your amplifier is doing.  You tell a lot by how it looks at the beginning and the end of the square wave. Here’s a picture I borrowed from a Stereophile review.


It isn’t important what this product is that the image is taken from.  Could be anything.  Let’s focus instead on how the example looks at the beginning of the square wave.  See the little “tit” or rise at the beginning?  The little sharp edge?  This will tend to sound a little bright when you have this rise.  You see this type of imperfection when you use feedback.  You can see it in other situations as well, but when it’s a result of feedback, there are sonic consequences.

I am sure the technocrats will howl over this, but I am simply sharing with you some years of experience.  If this tack-sharp blip is present in an amplification stage with GNFB (global negative feedback), almost invariably the amp will have a hard or slightly bright sound indicative of that type of topology.  Yes, a designer can add a capacitor to smooth out the little tit, but that in itself will not help the sound, only the way this looks on the scope.  If the tit is present because of feedback, lowering or eliminating the feedback is one surefire way to get better sound.  It’s also possible to fix the open loop circuit (no GNFB) such that when you close the loop (add back GNFB), the tits aren’t present.  But that’s fodder for another discussion.

This is the kind of stuff you find out over years of looking at scopes and listening to the sound of circuits.

Now take a look at this square wave.

good one

See how nice, rounded and gentle this looks?  Compare it to the other one.  If you see this type of response on your scope and it’s the output of a simple circuit with or without GNFB the audible results will be far nicer sounding (e.g. musical).

This is the stuff we nerds get excited over at work.  Is it any wonder I am antsy about listening to the new circuit?