Measurements and the Correlation of What We Hear

[fas42]

My discussion with Floyd was around his statement that humans easily hear linear distortions and that there is no difference between people in their ability to hear the same. I asked him then why it is that training does help with hearing compression artifacts. His answer was that non-linear distortion is indeed impacted by training and audibility does vary therefore between people. He went on to say that audio equipment has too little non-linear distortion for that factor to matter.

...

I will stop here to get some reactions .

My reaction is that I'm staggered that someone in the industry could say that: a bit like saying cars with tyres stop you feeling any bumps in the road ...

Frank

 

[DonH50]

Measuring capacitor hysteresis is not terribly complicated but takes a good set-up. A lot of measurements are not straight-forward and require some serious gear, though less nowadays, but the measurement noise and distortion floor for decent equipment far exceeds our ability to hear it. So, to me and IMO/IME, the real problem is making a valid set of measurements in-situ and then (the big one) correlating the results to what we hear (or worse, think/perceive that we heard). To take a very old example, the TIM problem was not that we couldn't measure it, it is that we did not know what to measure.

The eternal cry that we can't prove it by the measurements, including things like comparing two peices of gear, is more often an example of not having the time and resources to do so. It is easy for subjectivists to say "you can't/haven't measure that" when the logistics and resources to do so are time- and cost-prohibitive for most of us. I have seen the opposite happen, however, when an objectivist claims we did not hear something because we did not measure it (see TIM exanple above for the classic case). Perhaps ARC has clear mesurements comparing two preamps or power amps, but for most of us that's a hard thing to do. Now, if someone wants to loan me a couple of peices of ARC gear, I'd be glad to give it a go... BTW, I measured my modified SP3a1 many years ago and was amazed at how well it stood up to the then-current crop of SS preamps, back in the days when the goal was adding 0's to the distortion numbers.

 

[mep]

But the point would be, what conventional measurement technique would clearly show the effect of changing those caps when comparing the numbers before, and the numbers after?

Frank

Again, you are making my point.

 

[JackD201]

Are components now better than before? I wouldn't say so in the general sense but I would say that making a product better today should be easier. Mainly because there are references to actually beat, a broader availability of parts, technological advancements in these parts from materials, fabrication, quality control and the like, availability of more accurate measuring and testing equipment. Every year there are just more shoulders to stand on especially with the democratization of knowledge provided by the net.

The harder question is, ARE they better? Even within one company a new product may be better than a prior one on paper but customers of that brand might not consider it so. Mark's question is thus apt. What measurements do matter most? I don't know. At this point published measurements are useful to me to determine what may or may not work in my system, thus helping me narrow down candidates, but they're not enough to guarantee satisfaction.

I'm also torn between going with what I instinctively like and having to know why I like it. In a hobby meant to deliver pleasure, I often ask myself why I should intellectualize every little thing. There's a need for it for sure but there should be a time to switch that friggin switch off.

 

[steve williams]

There is, IMO, one incontrivertable fact, that is:

A hearing test, with sinewaves, or square waves, or triangle waves, or music at a lot of discrete volumes, can be used to record your ability to hear it or not and at what volume and frequency and thus, yes, measurements can correlate with hearing...........but, what happens inside your head as far as how accurate that sound is, well, there ain't no correlation. As I have said also before, the stereo image depth, stage, etc., is what happens in your brain. Yes, you can design speakers or record tricks to get exaggerated soundstage etc, but each persons brain will react or reconstruct it a bit differently.

I am saying that there is nothing in audio electronics signals that can not be measured, and its just a matter of how complex (how many tones, waveforms, nulling of signals, blah blah) that you want to do to slice down the differences in how any single amplifying device passes the signal through.

And maybe, since our hearing is not as good as it once was, perhaps we just don't hear the things that irrated us as much (thinking of excess treble and irration for example in early cd recordings/players...if you can't hear past 8 khz those frequencies might as well be light waves since your apparatus can not hear it, and that can be proven by measurments.

My opinion, when folks argue that an amp with 0.00003 percent TOTAL harmonic distortion across the frequency band sounds sterile, well, they are used to a lot of coloration. No problem with that. I am the first to pronounce manipulating sound to ones satisfaction by whatever means pleases you.

Hearing as a physical measurable thing, we can do.......perception or preference are in the minds of the beholders...

I would also add that re-capping an amp will make it sound different than with the 20 year old caps, but some of those old caps "held on and re-released the signal" and thus can be considered more musical.........just something to chew on Mark.

Tom

IMO Tom has hit the nail right on the head and the part in particular is highlighted in bold.

IOW "is flat where it's at or is it the use of some coloration?"

I can remember back in the 60's the introduction of the "tone control" which started it all.

 

[mep]

The short story however Mark is that if you can hear a difference it can be measured. I'm not an engineer or a physicist etc but I like to think myself educated. I did take physics for several years including sound as did you. Science is science. Listening does not trump science.

Steve-I'm not saying that listening trumps science. People love to say that if you an hear a difference, it can be measured. What I'm asking is where are those measurements? That is my whole point to this thread. Saying we can measure it but we don't doesn't get us there. Surely there are subjectivists here that have upgraded their system electronics and feel strongly that their new purchase is better sounding than the gear it replaced. Where are the measurements that will show it? That is my question. To tell me that we can measure it, but it's expensive, time consuming, etc. and that's why we haven't measured it is no better than someone who says he doesn't need measurements to know that what he is hearing sounds better than the gear he replaced.

 

[amirm]

Amir,
Can you explain this key sentence "His answer was that non-linear distortion is indeed impacted by training and audibility does vary therefore between people. "? Thanks.

This was a short conversation but I am going to say that his answer was relative to very low measured distortions such as THD relative to his field of interest, speakers and rooms. Clearly he considers the former a negligible factor.

 

[fas42]

I'm also torn between going with what I instinctively like and having to know why I like it. In a hobby meant to deliver pleasure, I often ask myself why I should intellectualize every little thing. There's a need for it for sure but there should be a time to switch that friggin switch off.

I am perhaps fortunate, or very unfortunate, in that it has been driving me crazy for decades knowing that there are differences but not fully understanding why, not even now. The engineer and perfectionist in me is driving me hard to acquire that understanding, I certainly have a lot of experimentally developed techniques at my disposal, but I certainly could not give clear answers that would satisfy all rationalists as to why a certain procedure does the job.

This gets back to Mark's lament, following Don's comment, that it is still all too hard: expensive, time consuming, disinterest by the people who could do it, to find all the answers ...

Frank

 

[MylesBAstor]

I am perhaps fortunate, or very unfortunate, in that it has been driving me crazy for decades knowing that there are differences but not fully understanding why, not even now. The engineer and perfectionist in me is driving me hard to acquire that understanding, I certainly have a lot of experimentally developed techniques at my disposal, but I certainly could not give clear answers that would satisfy all rationalists as to why a certain procedure does the job.

This gets back to Mark's lament, following Don's comment, that it is still all too hard: expensive, time consuming, disinterest by the people who could do it, to find all the answers ...

Frank

Let the academicians figure out why. These are small co's and don't have the time or resources to devote to figuring out the minutiae. OTOH, someone like Harman or Krell might have the resources.

 

[Phelonious Ponk]

It's how audio electronics don't sound that interests me.

Tim

 

[fas42]

Actually, there is a very simple extension of conventional techniques that would be extremely telling for stereo amps, I've mentioned this before. Do a distortion test on one channel only, at a low power output level. Repeat this test, with the other channel with null input, and then with steadily increasing output right up to maximum level on the other channel. A "perfect" amp will show no variation in the distortion of the first channel, but of course as the power supply gets more and more stressed from feeding the second channel a real amp will show distinctive variations in distortion figures.

Frank

 

[FrantzM]

Let the academicians figure out why. These are small co's and don't have the time or resources to devote to figuring out the minutiae. OTOH, someone like Harman or Krell might have the resources.

So how do they design their gears to be "better" if they don't have the time and resources to figure out the minutiae ...???

I would add that a product which is add coloration will have to do so consistently ... doesn't that add things to the recording that weren't there consistently?
Pleasing it might be. Hi-Fi? I have my doubt...

Now I tend to think that we are not measuring the right parameters ...or that our protocols could be improved. For example we have fallen in love with THD. It has been shown that we can take up to 50% of THD without even noticing it !!!! yet it is hard for me to accept that all electronics sound the same. So what account for the differences.\? I reject the view that we can't measure what we can reliably hear. The very fact of recording is measurement. If we can record it we can measure it ...

 

[MylesBAstor]

So how do they design thei gears to be "better" if they don't have the time and resources to figure out the minutiae ...???

'Cause it's not cause-effect and one can come up with 10 explanations as to why what they changed in the circuitry did what it did. Circuits aren't much different than biology-change one thing and you affect numerous paths.

I would add that a product which is add colorations will have to do so consistantly ... doesn't that add things to the recording that weren't there consistantly? Pleasing it mught be.
Hi-Fi? I have my doubt...

Now I tend to think that we are mnot measuring the right parameters ...or that our protocols could be improved. For example we have fallen in love with THD. It has been shown that we can take up to 50% of THD without even noticing it !!!! yet it is hard for me to accept that all electronics sound the same. o what account for the differences.\? I am not yt convinced that they all sound the same. I reject the view that we can't measure what we can reliably hear. The very fact of recording is measurement. If we can record it we can measure it ...

I keep hearing this adding colorations statement over and over again. I don't know any designer of any cutting edge product, for instance Krell, Rowland, cj, ARC, VAC, Spectral, etc, that nowadays doesn't strive for neutrality? OTOH, too paraphrase HP, if all these products are supposed to represent real music, how come they all sound so different? I'm sure Krell and Spectral sport top notch measurements, yet I don't think there's anyone here who would mistake a Krell for a Spectral amp.

 

[amirm]

I keep hearing this adding colorations statement over and over again. I don't know any designer of any cutting edge product, for instance Krell, Rowland, cj, ARC, VAC, Spectral, etc, that nowadays doesn't strive for neutrality?

Agree that it is hard to add coloration to amplifiers as such an act quickly shows up in the measurements. On the other hand, speakers are manipulated to have a specific coloration all the time and that is the main technique to drive sales.

 

[FrantzM]

'Cause it's not cause-effect and one can come up with 10 explanations as to why what they changed in the circuitry did what it did. Circuits aren't much different than biology-change one thing and you affect numerous paths.



I keep hearing this adding colorations statement over and over again. I don't know any designer of any cutting edge product, for instance Krell, Rowland, cj, ARC, VAC, Spectral, etc, that nowadays doesn't strive for neutrality? OTOH, too paraphrase HP, if all these products are supposed to represent real music, how come they all sound so different? I'm sure Krell and Spectral sport top notch measurements, yet I don't think there's anyone here who would mistake a Krell for a Spectral amp.

Not cause and effect ????? What is it then ? Color me befuddled

Now about the fact hat a Spectral sounds different from a Krell. If they were perfect they would both sound the same i-e perfect.. They are not and their differences illustrate the different approach taken ... If it weren't clear enough I don't think I can infer the sound of an equipment from its specs sheet.. I am not sure anyone can ... So that a particular set of measurements shows similarities doesn't mean same sound ... but these results could point toward some similarities in sound ...

 

[fas42]

Agree that it is hard to add coloration to amplifiers as such an act quickly shows up in the measurements. On the other hand, speakers are manipulated to have a specific coloration all the time and that is the main technique to drive sales.

We are now arguing semantics: if two amplifiers sound different then one or other, or both, is adding distortion, colouration to the sound. Whether it is intentional or not, the colouration is there, otherwise the Krell would sound identical to the Spectral.

Mark's point is that the colouration we're worrying about is subtle, not obviously staring you in the face and easy to measure. Of course, I have my own point of view about what's happening here, but we won't open that can of worms ...

Frank

 

[RogerD]

If it can be heard it can be measured.

Can it really?? Maybe in the macro,but what about greater clarity when changing two 4uf coupling caps? or changing between resistors of the same value.

Take a 55 year old piece of equipment and do a total recap,based on your knowledge and experience of voicing using this and that brand of capacitors and resistors,every value is the same,but as expected the change yields greater clarity and dynamics. All values remained the same and measured within tolerance. Plus the change effects overall tonal balance.

Just like tube rolling,measurements can not explain the sonic difference. Audio will always be the sum of knowledge,science and art.

 

[andy_c]

If the results of an uncontrolled experiment cannot be explained by science, is that a failure of science? If not, whose failure is it?

How many experiments by audiophiles could be considered controlled experiments? Let's say, comparing amps. Let's forget about the contentious issue of blind testing and only consider level matching. How many audiophile amp comparisons are level-matched? And of these, how many allow for comparison of the amps within the very short time span of auditory memory? This is not easy, as it involves some kind of DIY effort to construct a switching mechanism of some kind.

Then, in rare cases when such controls are put into place, how many reject the results because they imply a conclusion that's rather mundane, and which contradicts preconceived notions?

From my perspective, what it comes down to in a lot of cases is a claim of "science cannot explain why X is true", when X has not been demonstrated to be true in the first place. Most audiophile experiments aren't even worthy of consideration in the scientific sense to begin with, as they are typically totally uncontrolled. And that's fine if the idea is to have fun - we all want to do that. But if one wishes to go beyond that into the realm of fact, there's homework that needs to be done. Unfortunately, the audiophile hobby is beset with roving packs of homework-eating dogs .

 

[fas42]

Sorry, I would beg to differ, Roger, that subtle change for the good would be measurable, as the thread title is calling for. The big headache is knowing what the correct measuring tool is, or if you have such a device, exactly how to apply it. The clumsy attachment of one piece of kit in a laboratory setting to a host of electronic gizmos is equivalent to dragging a person who's feeling out of sorts into a hospital, hooking up a gaggle of impressive looking, expensive doodahs, pushing all the go buttons and out pops the answer: here's exactly what's wrong with you. Yeeeaaah, right ...

Frank

 

[fas42]

If the results of an uncontrolled experiment cannot be explained by science, is that a failure of science? If not, whose failure is it?

Or a controlled one ...

Here we are, worrying about silly old audio, yet at the moment we've got the chance to knock one of the biggies of science on the head: the old "you can't go faster than light" thingy. Just when you think it's safe to go outside, along come some mongrels and give one of your cherished beliefs a whack on the skull! Ain't anything sacred ...???

Frank