Sound Quality Vs. Measurements

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An old debate, repeated over and over. He states his opinion in the first paragraph, so the rest of the article is not surprising. Of course if he is wrong, then we don't need audio salesmen or reviewers as the engineering facts would speak for themselves. Turkeys may be sincere, but they don't vote for Christmas! If he is right, then we can throw away our oscilloscopes and data sheets and just fiddle with 'designs' until they 'sound right'.

I suspect the truth is more complex. There are other threads on here which discuss the same issues so there seems little point in yet another one.
 
DF96: Note his bio.

Steve Guttenberg

Ex-movie theater projectionist Steve Guttenberg has also worked as a high-end audio salesman...and works as a freelance writer for Home Theater, Inner Fidelity, Tone Audio, and Stereophile.

One assumes that he's unaware of the huge amount of excellent work correlating measurement with perception done by actual trained engineers and psychoacousticians. Or doesn't want to risk the pay and free toys that go with those writing gigs.
 
Agreed.

Thanks.


An old debate, repeated over and over. He states his opinion in the first paragraph, so the rest of the article is not surprising. Of course if he is wrong, then we don't need audio salesmen or reviewers as the engineering facts would speak for themselves. Turkeys may be sincere, but they don't vote for Christmas! If he is right, then we can throw away our oscilloscopes and data sheets and just fiddle with 'designs' until they 'sound right'.

I suspect the truth is more complex. There are other threads on here which discuss the same issues so there seems little point in yet another one.
 
IMO it depends on what kind of distortions are present. IM distortions and HF stuff like crossover degrade sound. Odd harmonic spectrum patterns are not so good either. Many prefer softer even harmonics and believe they add charactor to the sound. Personally I strive for transparency. Generally high BW amps with adequate damping and current slew that shift the distortion spectrum to low levels at very high frequencies tend to sound more transparent but there is certainly a bit more to it than that.:mischiev: Everyone seems to like to blames the amp and not the speakers/enclosures and the listening room.:rolleyes:
 
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As DF96 said the truth might be somewhere in the middle.

But surely Guttenberg states the obvious, that is a matter of perceptual evalution to decide if the interpretation of measurement results is already sufficient or not.

Up to now this position is common sense in the audio field, otherwise listening tests were not necessary anymore.
 
"I can show you six areas in the JC 2 where I can change parts that will change the sound but not change the measurements"

Thats' a quote by Richard Schram, president of Parasound, on the JC2 preamp, the production version of the Blowtorch, designed by no other than the famous John Curl.

I think this is a good quote because while my electronics knowledge is not great (or even good) I know that this is an extremely good design by itself. But they didn't put it together by blindly choosing "well functioning" parts. The original design even used a specialist to choose the best sounding parts for the right purpose. So yeah it is obvious to a lot of us that it takes both measuring and listening to create a good piece of gear. But not to everybody, but I think people need to learn this. And in my recent experience with purchasing a second hand Mccormack amp, and knowing the designer's philosophy and history, Im now even more convinced to believe more in parts selection, layout, and a killer power supply than i do in pure design. But hey, what do I know.. we never stop learning.
 
It is undeniable that the full suite of relevant measurements available to characterize audio gear will likely not reveal every possible nuance of sound. It is far more undeniable that the human senses unaided are open to wildly self-delusional inferences and conclusions, and centuries of experience highly recommend an objectively refutable approach to understanding the universe, including audio. Wise observers will use both measurements and their ears together, but great caution is required when we sail the ship unaided by compass or sextant and expect to reach the correct destination.
 
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Every now and then this subject comes up to remind us how foolish we all are. I believe in this, I believe in that.....

Looking for an universal truth? Well, I'm sorry to disappoint you - you won't find any here. Yes, people like talking for the pleasure of talking which is what I'm doing right now but that is well known and as far as universal truth goes, it isn't the most interesting one. Haha.

Moot points, wanna check if a different cap gives better sound? That's easy, grab a soldering iron and hear for yourself. Enjoy it and STFU because your system it's not my system, and if you're selling to others don't STFU just tell the whole world how bloody good those caps are.
 
"It depends" The only true statement. Here is my quandary. Being an engineer, I want real measurements. I want to see something different in the transfer function. On the other hand, I have no question at all how different amps sound, all measured below my equipment threshold and what we are SUPPOSED to be able to hear. I also know my wife has sensitivities that confound and amaze. She can yes/no within seconds any amp or speaker. I have tried to fool her. Nope. Perfectly consistent. So, my long term goal is to figure out what on earth she is hearing and then measure that.

I have one picture of a sequence of three half wave pulses at 4Khz computer generated and played back through various amps. I find a frequency compression in the initial wavefront in amps she does not like, and less in amps she does. Just for a reference, She likes my old Rotel and Creek but did not like any of my tube amps, Hafler or B&K. I think I hear part of what she is complaining about, but not reliably enough that I trust it to be objective. I am too poor to have a Bryston, Krell,or Levinson as references. She DID like the original Cary triode in a store.

On The King James Version, CD of the original LP, when Harry really gets hard on the horn, there is some slight edge that does not happen in real life. On Clapton Unplugged, the audience noise is just plain bad, but some amps make it worse. On Bream Plays Segovia, some amps make his strings sound metal.

What I am suggesting is whatever we should measure is dynamic in nature. I doubt it is linear. I can't directly correlate just bandwidth, but wider bandwidth amps seem to far better as a general rule ( over 50K ). Generous supplies tend to fair better. Good physical layout tends to fair better. I can't point to any parameter, topology or components on a 100% repeatable measurement correlated to her ears. I have had over 35 years to do this and no luck yet. I remember when we switched focus form HD to TIM. We all thought that was the key. Not yet.
 
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I also know my wife has sensitivities that confound and amaze.

Yes. I know what you're talking about. It's weird because it's uncommon and it's confusing because you don't know where it comes from. I also have it (intermittently) and that's why I think it's just too complex to understand and too complex to explain. Then you read some guy saying all amps sound the same....and you smile. :)

I can't point to any parameter, topology or components on a 100% repeatable measurement correlated to her ears. I have had over 35 years to do this and no luck yet.

Again, I hear you. Over 15 years and all I can say is that I have no idea. I gave up trying to understand - it beats me. The only sure thing I know is that I tend to like the sound of triodes. I'm clueless about ideal parts and topology.
 
tvrgeek said:
I have one picture of a sequence of three half wave pulses at 4Khz computer generated and played back through various amps. I find a frequency compression in the initial wavefront in amps she does not like, and less in amps she does.
A half-wave pulse has infinite bandwidth (although finite slew rate), so all (finite-bandwidth) amps will modify it in some way. Testing audio amps with a non-audio test signal is of course an interesting exercise, but you then have to try to read across to how the amp will behave with an audio signal.

"frequency compression in the initial wavefront": this is mixing frequency and time domain descriptions. Could you show us some of your results? My guess is that most of what you are seeing is simply low-pass filtering, but the phase response around the roll-off point could have some effect. The really interesting part would be any residual non-linear effects, as you surmise.
 
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