Master Thread: Are Measurements Everything or Nothing?

[satow]

Not hearing a difference between audio electronics is actually a good thing. It means the stuff has gotten better than our ears, we can decide by practicality, features, price and aesthetics instead, save a lot of money, and focus on what really counts instead: enjoying some good fucking music.

I agree regarding the enjoyment of listening to music.

 

[ahofer]

“If you can't hear the difference, that is your problem, not mine.“

It would be a problem if it caused us to use our resources in an unproductive pursuit or made us unhappy. So it certainly isn’t a problem in either of those senses. Whether it is a problem for you is more difficult to ascertain.

 

[Miguelón]

I am not confusing you. Someone else did. Here is a quote from the article:

Tice claims that TPT "programs" the electrons to flow in a more direct path.

You don’t “program” electrons. They don’t collide with the conductor atoms; they are a part of the atoms. Stereophile is not a scientific publication.

The science is well understood. It is outrageous that someone claims to discover some physical behavior with ZERO proof, measurements, explanations, just made up stuff. Note that the “concept” did not take hold outside of the audiophile community.

Electrons are subject to five fundamental physical laws. Electrons behavior is subject to electric fields and magnetic fields, which is “connected” to voltage, current and power. We don’t deal with programing individual electrons. (see Heisenberg principle).

But putting the programed electrons story aside, we do deal with “massive amount” of electrons which forms electric signals.

Clock signals are measurable. There are low and high voltage levels, rise and fall time, jitter, possible cable reflections (poor termination). There are solid theory and good equipment to view and measure it all very precisely.

So again, the idea of digital sampling of signals (audio, video, MRI, communications….) is based on equal time between samples. A time error will distort the waveform. That is what counts, and what is measurable.

Perhaps Stereophile will claims that Caesium clocks in high performance audiophile level DACs will soon set new standards for the second, in the International Bureau of Weights and Measurements…

 

[Miguelón]

LOL! I get what you’re saying, but the idealized “perfectly transparent gain block” doesn’t describe how real analog stages behave. Spatial cues come from the recording, but different circuits preserve or collapse those cues to different degrees because of phase behavior, noise modulation, harmonic structure, and load interaction.

Nobody’s claiming a preamp creates holography. The point is that some designs maintain microdetail and depth better than others.

And yes—your FLAC example shows exactly why the type and envelope of distortion matters. That same principle is why different gain stages can sound different even when they measure clean.

If they measure “clean” that means precisely that are beyond human threshold of discrimination: that’s the definition of ‘clean’.

The room response will modulate your recording orders of magnitude higher than minimal differences between one amp and another.

 

[Jaxx1138]

Well, that Cult part might be true. But the measurements do matter.

 

[ahofer]

The point is that some designs maintain microdetail and depth better than others.

Has anyone proven the existence of ‘microdetail and depth’ that is audible yet unregistered by our measurement technologies? We are all ears, as it were. Seems like a simple thing to show, if true.

Until then, forgive us if we cling stubbornly to the null hypothesis.

Sorry this is redundant. But:

What your adding is a LOT of distortion and non-linearity in response.
Over 60db worth of noise and distortion going from the passive mode to the active tube mode.

That explains it! The components are ADDING ‘microdetail’ plainly in the measurements! Now that is entirely plausible.

 

[Ropeburn]

Has anyone proven the existence of ‘microdetail and depth’ that is audible yet unregistered by our measurement technologies? We are all ears, as it were. Seems like a simple thing to show, if true.

Until then, forgive us if we cling stubbornly to the null hypothesis.

To pick up the wording:

The human ear can hear milli- but not microdetail.

 

[rdenney]

Has anyone proven the existence of ‘microdetail and depth’ that is audible yet unregistered by our measurement technologies? We are all ears, as it were. Seems like a simple thing to show, if true.

Until then, forgive us if we cling stubbornly to the null hypothesis.

Sorry this is redundant. But:


That explains it! The components are ADDING ‘microdetail’ plainly in the measurements! Now that is entirely plausible.

This is something poorly understood by those who eschew technical understanding. A sine wave at, say, 58 Hz (a low B-flat) is just this deep hum with almost no definition to it. Make it loud, and it's just a bigger hum that maybe reverberates in the room to become louder still. But it's still very poorly defined unless it rattles something in the room. But distort it at just 1%, and now you've added a stack of overtones to that deep sound that range up to frequencies that we hear with greater definition. I've played sine waves on the bench and can easily tell the difference between 0.002% distortion (such as produced by my HP distortion analyzer's test oscillator) and 1% (as produced by my budget-level Tektronix signal generator). Of course, sine waves are easy because they provide no masking in a test like this, but they help to illustrate the point I'm making.

When I play a tuba, the sound has a range of overtones baked into the characteristics of the instrument, and these may even be louder than that 58-Hz fundamental. Were it not so, the notes in the bottom octave of a contrabass tuba, the fundamentals of which are below 64 Hz, would be nearly unhearable. But those overtones provide two features: 1.) definition by including frequencies that are much easier to hear, and 2.) a characteristic tone that identifies the instrument and also changes with the energy being put into the sound by the performer. So, the tone very much provides cues on the intended loudness and power, which is at least as informative as the actual change in SPL. Partly, it's because the added higher harmonics are easier to hear, and partly it's because those added higher harmonics change the character of the sound which the listener interprets as the performer's intent to be more powerful. Musicians of all instruments (including singers) learn how to play at low SPL while still introducing cues of loudness, and also has to play loudly (as measured) while minimizing those changes in tone. For example, I can play a low F as a pedal tone on my bass tuba in F, such as the lowest note in the Vaughan Williams Concerto for Tuba cadenza in the first movement. But with my six-valve F tuba, I can also play it with all the valves down--no longer a pedal tone but now played on the next harmonic up but with a bugle that is now twice as long. Same note, but much different tone and character, and it simply sounds more energetic even when it isn't louder. Musicians also do this because they know their sound will be smeared by the reverberation in the hall, and they want a sound that won't get lost in that reverberation. It is not their objective to sound great up close, but to sound as they intend "out front".

So, we are trained from listening to real instruments performed by real musicians to interpret higher harmonic content as being louder or more powerful and with greater definition. It's no wonder that a playback system that adds some distortion, thus increasing the harmonic content, will sound more defined--more crisp. People whose skill is more in word choice might use a word like microdetail.

The problem, of course, is that is is less realistic--the instruments should be adding overtones and distortion based on the intentions and skill of the musician, not the playback system. Musicians would usually prefer to be in charge of that tone, and I as a listener of recorded music am more interested in what the musicians do than in what the amp designer does.

Rick "distortion can be exciting" Denney

 

[Alan O]

So, we are trained from listening to real instruments performed by real musicians to interpret higher harmonic content as being louder or more powerful and with greater definition. It's no wonder that a playback system that adds some distortion, thus increasing the harmonic content, will sound more defined--more crisp. People whose skill is more in word choice might use a word like microdetail.

That - and the rest of it - is a fascinating insight. Thank you!

 

[Ropeburn]

This is something poorly understood by those who eschew technical understanding. A sine wave at, say, 58 Hz (a low B-flat) is just this deep hum with almost no definition to it. Make it loud, and it's just a bigger hum that maybe reverberates in the room to become louder still. But it's still very poorly defined unless it rattles something in the room. But distort it at just 1%, and now you've added a stack of overtones to that deep sound that range up to frequencies that we hear with greater definition. I've played sine waves on the bench and can easily tell the difference between 0.002% distortion (such as produced by my HP distortion analyzer's test oscillator) and 1% (as produced by my budget-level Tektronix signal generator). Of course, sine waves are easy because they provide no masking in a test like this, but they help to illustrate the point I'm making.

When I play a tuba, the sound has a range of overtones baked into the characteristics of the instrument, and these may even be louder than that 58-Hz fundamental. Were it not so, the notes in the bottom octave of a contrabass tuba, the fundamentals of which are below 64 Hz, would be nearly unhearable. But those overtones provide two features: 1.) definition by including frequencies that are much easier to hear, and 2.) a characteristic tone that identifies the instrument and also changes with the energy being put into the sound by the performer. So, the tone very much provides cues on the intended loudness and power, which is at least as informative as the actual change in SPL. Partly, it's because the added higher harmonics are easier to hear, and partly it's because those added higher harmonics change the character of the sound which the listener interprets as the performer's intent to be more powerful. Musicians of all instruments (including singers) learn how to play at low SPL while still introducing cues of loudness, and also has to play loudly (as measured) while minimizing those changes in tone. For example, I can play a low F as a pedal tone on my bass tuba in F, such as the lowest note in the Vaughan Williams Concerto for Tuba cadenza in the first movement. But with my six-valve F tuba, I can also play it with all the valves down--no longer a pedal tone but now played on the next harmonic up but with a bugle that is now twice as long. Same note, but much different tone and character, and it simply sounds more energetic even when it isn't louder. Musicians also do this because they know their sound will be smeared by the reverberation in the hall, and they want a sound that won't get lost in that reverberation. It is not their objective to sound great up close, but to sound as they intend "out front".

So, we are trained from listening to real instruments performed by real musicians to interpret higher harmonic content as being louder or more powerful and with greater definition. It's no wonder that a playback system that adds some distortion, thus increasing the harmonic content, will sound more defined--more crisp. People whose skill is more in word choice might use a word like microdetail.

The problem, of course, is that is is less realistic--the instruments should be adding overtones and distortion based on the intentions and skill of the musician, not the playback system. Musicians would usually prefer to be in charge of that tone, and I as a listener of recorded music am more interested in what the musicians do than in what the amp designer does.

Rick "distortion can be exciting" Denney

Good heavens, how inhumanly complicated is all that? Makes me realise once again why I prefer synthesizers. At least then you only have to worry about the interactions of six FM operators, or wavetable scanning, granular sample playback, or analog oscillator PWM or hardsync or ringmodulation between them. And simply assign various parameters to the usual physical controls for expression and 1000 ways of harmonic characteristics control.

All simple stuff easy to understand, and at least real instruments for real musicians. Not these overcomplicated acoustic contraptions that on top of it all are a pain to record...

 

[Sal1950]

That explains it! The components are ADDING ‘microdetail’ plainly in the measurements! Now that is entirely plausible.

Meow

 

[Newman]

That - and the rest of it - is a fascinating insight. Thank you!

Best to treat it as an untested hypothesis with regard to playback equipment.

 

[bmc0]

So, we are trained from listening to real instruments performed by real musicians to interpret higher harmonic content as being louder or more powerful and with greater definition. It's no wonder that a playback system that adds some distortion, thus increasing the harmonic content, will sound more defined--more crisp. People whose skill is more in word choice might use a word like microdetail.

Where it gets less clear (pun intended) is when multiple notes are put through the same wideband distortion generator. Many instruments only play one fundamental pitch at a time, and those that can play multiple fundamentals usually do not generate high-level intermodulation products (distorted electric guitar being a notable exception).

 

[rdenney]

Best to treat it as an untested hypothesis with regard to playback equipment.

I think it’s fair to say that many observers prefer added harmonics in the sound of playback equipment. Atkinson said as much at an Axpona talk years ago, when he suggested lots of even harmonics may make an amp more sellable to audiophiles.

Overtones are music when made by the instrument or harmonic distortion when made by the playback equipment. The difference between the two may not be much in terms of frequency, amplitude, and phase. It’s a policy question in my mind—I prefer as a matter of policy a playback system that preserves the characteristic tone of the instrument as played and recorded in the recording space.

The untested hypothesis is whether added harmonic distortion is a source of additional perceived detail. It seems to me even clipping could be that, if not too obvious, so I doubt it’s the only source.

Famously (and perhaps apocryphally), Bob Moog made a mistake in the oscillator of the first Moog synthesizers, overdriving an amplification stage in the tone generator and creating a surplus of second harmonic distortion. It apparently is credited with the carrying power that allowed keyboardists to compete with guitarists in rock music.

All this is entirely measurable, of course.

Rick “certainly hears plenty of harmonic distortion in early synths, but doesn’t want the playback system to be adding more” Denney

 

[Mart68]

I think it’s fair to say that many observers prefer added harmony in the sound of playback equipment. Atkinson said as much at an Axpona talk years ago, when he suggested lots of even harmonics may make an amp more sellable to audiophiles

But he has a vested interest in promoting the idea that amplifiers have a sound.

Isn't it the case that harmonic distortions in amplifiers are way below what we can hear? (Some rare edge cases excepted ofc).

 

[rdenney]

But he has a vested interest in promoting the idea that amplifiers have a sound.

Isn't it the case that harmonic distortions in amplifiers are way below what we can hear? (Some rare edge cases excepted ofc).

I seem to recall a hint of irony in what John said. He was postulating why an amp might be preferred over something like a Benchmark AHB. His comment was off the cuff at the end of a panel discussion—what amp would sell well to audiophiles?

The question of what we can hear depends on a range of contexts. I have conducted my own experiments with a pure sine wave played through decent but old speakers, and harmonic distortion in the 1% range (-40 dB) is clearly hearable. -25 dB starts to sound like a MiniMoog. -60 dB is detectable—the sound of a distortion analyzer oscillator through an old amp. A pure sine wave is an unrealistic test, of course—an edge case—but it tells me those harmonics are there even when masked by music. They are measurable even if inaudible, which is relevant to this thread. I can’t hear distortion in real music worse than the middle -30’s dB, showing the effects of masking (at least with the music used for that test).

Rick “said all this before” Denney

 

[Gregss]

But he has a vested interest in promoting the idea that amplifiers have a sound.

Isn't it the case that harmonic distortions in amplifiers are way below what we can hear? (Some rare edge cases excepted ofc).

For decent, quality equipment, yes. But some love tubes and their distortion. Which is fine, just don't pretend they don't distort.

 

[Ropeburn]

I think it’s fair to say that many observers prefer added harmonics in the sound of playback equipment. Atkinson said as much at an Axpona talk years ago, when he suggested lots of even harmonics may make an amp more sellable to audiophiles.

Overtones are music when made by the instrument or harmonic distortion when made by the playback equipment. The difference between the two may not be much in terms of frequency, amplitude, and phase. It’s a policy question in my mind—I prefer as a matter of policy a playback system that preserves the characteristic tone of the instrument as played and recorded in the recording space.

The untested hypothesis is whether added harmonic distortion is a source of additional perceived detail. It seems to me even clipping could be that, if not too obvious, so I doubt it’s the only source.

Famously (and perhaps apocryphally), Bob Moog made a mistake in the oscillator of the first Moog synthesizers, overdriving an amplification stage in the tone generator and creating a surplus of second harmonic distortion. It apparently is credited with the carrying power that allowed keyboardists to compete with guitarists in rock music.

All this is entirely measurable, of course.

Rick “certainly hears plenty of harmonic distortion in early synths, but doesn’t want the playback system to be adding more” Denney

That may have been a mistake initially, but since then it's a staple feature in many synths, usually implemented as filter input overdrive. Very easy to do, just set gain of oscillator mixer and/or buffer accordingly. On higher values it even bleeds into filter frequency control, giving a bit of filter FM, further adding all kinds of complex harmonics. Rich, adjustable, dynamically playable, which is what you want for flexibility of sound design.

Waldorf Pulse for example got nasty gain in the oscillator mixer, overdriving filter input from volume 30-40 (of 127). Highly useful and largely responsible for the hard and aggressive sound it's known for. Indeed as you said: cuts through any mix without additional processing. Add a hot output of 5V max, making it easy to overdrive the usual mixer inputs, and you got a monster.

Or sometimes it's non adjustable, but still deliberate. Vermona Perfourmer got an ever so slight but audible overdrive between oscillator and filter. Users frequently state it "sings beautifully", even if you use the sine waveform. You don't want it perfectly clean; that would be good for control purposes but sound rather boring. You want those harmonics.

People found out because you can circumvent it by patching the VCO out directly to another voice's VCF input, then you get a much cleaner sound.

 

[Sal1950]

Isn't it the case that harmonic distortions in amplifiers are way below what we can hear? (Some rare edge cases excepted ofc).

But some love tubes and their distortion

Yes tubes may be the glaring exceptions but there are also some cases of SS amps that play about with things. Pass Labs First Watt line of amps are some examples. Nelson seems to like kicking around with various design aspects to introduce a subtle distinctive sound to each one.


"First Watt SIT-3, Although that relatively high level of second-harmonic distortion, which is a deliberate design choice, is controversial, the First Watt SIT-3 is a well-engineered amplifier.—John Atkinson"

"If you have a chance, have a listen to the SIT-2 for an "audiophile experience" as another example of what high 2nd and 3rd harmonic distortion amplifiers sound like. As a solid state box (the Amp Camp Amp being the other solid state one I've examined with high distortion), this machine has the benefits of better reliability, won't wear out like tubes, and doesn't require much if any warm-up time. Archimago's Musings."

 

[Mart68]

Yes tubes may be the glaring exceptions but there are also some cases of SS amps that play about with things. Pass Labs First Watt line of amps are some examples. Nelson seems to like kicking around with various design aspects to introduce a subtle distinctive sound to each one.


"First Watt SIT-3, Although that relatively high level of second-harmonic distortion, which is a deliberate design choice, is controversial, the First Watt SIT-3 is a well-engineered amplifier.—John Atkinson"

"If you have a chance, have a listen to the SIT-2 for an "audiophile experience" as another example of what high 2nd and 3rd harmonic distortion amplifiers sound like. As a solid state box (the Amp Camp Amp being the other solid state one I've examined with high distortion), this machine has the benefits of better reliability, won't wear out like tubes, and doesn't require much if any warm-up time. Archimago's Musings."

Amps like the firstwatt are what I had in mind when I mentioned exceptions, it's worse than many tube amps especially the old school ones from the days when they were chasing the best distortion figures. And it's clipping at 8 watts so will always be clipping on peaks.

There's no similar explanation for why 50wpc NAD amps could sound different to 50wpc Rotel or Yamaha be different from Naim or any other 'normal' design. But Stereophile et al will still describe their individual 'tone' or 'character' as though reviewing a piano or guitar.