Who's afraid of DBTs

[trithio]

This may generate some controversy and I would apreciate if everyone forgot about trithio and posted to the subject.

The prevalent atitude on CA seems to be that science is useless when it comes to audio. Many people seem to be convinced that audio components are somehow build by wizards with sticks and clay. And particularly DBTs are hated with a passion worthy of a better cause.

 

I wanted to write a post about science, DBTs and audio but then I found a perfect quote in the most surprising place: Stereophile.

 

That is JOhn Atkinson interviewing J. Gordon Holt around 2005.

JA: Do you see any signs of vitality in high-end audio?

 

JGH: Vitality? Don’t make me laugh. Audio as a hobby is dying, largely by its own hand. As far as the real world is concerned, high-end audio lost its credibility during the 1980s, when it flatly refused to the kind of basic honesty controls (double-blind testing, for example) that had legitimized every other serious scientific endeavor since Pascal. [This refusal] is a source of endless dirisive amusement among rational people and of perpetual embarrassment to me, because I am associated with the mess my disciples made of spreading my gospel. For the record: I never, ever claimed that measurements don’t matter. What I said (and very often, at that) was, they don’t always tell the whole story. Not quite the same thing. Remember those loudspeaker shootouts we used to have during our annual writer gatherings in Santa Fe? The frequent occasions when various reviewers would repeatedly choose the same loudspeaker as their favorite (or least favorite) model? That was all the proof needed that [blind] testing does work, aside from the fact that it’s (still) the only honest kind. It also suggested that simple ear training, with DBT confirmation, could have built the kind of listening confidence among talented reviewers that might have made a world of difference in the outcome of high-end audio.

And my question is: why do you think JGH failed so miserably at steering audio in that science-based direction that he apparently values so much? Hypocrisy, helplesness, ....

[89reksal]

The prevalent atitude on CA seems to be that science is useless when it comes to audio. Many people seem to be convinced that audio components are somehow build by wizards with sticks and clay. And particularly DBTs are hated with a passion worthy of a better cause.

 

I'd have to disagree with this premise. I'm generally pretty quick to react to posts/threads where anyone is trying to impose their own beliefs on others. For whatever reason, most of these times seem to involve "objectivists" trying to tell "subjectivists" something can't be this way because of lack of scientific proof, measurements, DBT, etc. For me it's not a matter of thinking these factors are irrelevant. It's more of a sense that at this stage of computer audiophile development, the science as currently understood isn't advanced to the point where it's able to suitably explain some of the more subjective listener impressions. This also applies to measurements. I personally believe that science at this point doesn't even know what actually needs to be measured, so asking for measurements to prove everything is kind of pointless and probably more accurately, unfair. Even if we knew what exactly to measure, is the equipment needed to perform these measurements even available? Or more importantly, would it be readily available to someone at the hobbyist or small entrepreneur level? Based on different comments from some of the participating manufacturers, it seems that the cost of even currently available measuring equipment is prohibitive, making it impractical for most to perform any kinds of experiments.

 

On this same note, something like the Mitchco tests on JPlay, using AudioDiff Maker seem almost laughable, especially when we see people that are normally the first to ask for more objective based explanations, being the first to be so willing to accept these types of tests as any kind of final proof. My own viewpoint on these results is sure, the test performed may have shown that result. But I can't make the leap from that into believing that a test performed with a free piece of internet downloaded software is supposed to be able to measure things that most currently available test equipment is unable to measure.

 

As far as DBT's, I don't have any kind of scientific background, so I may not understand exactly how they're done, but to me it basically comes down to trusting someone else's listening impressions to make a decision. That entire concept doesn't work for me. No matter what I read or hear about, audiowise at least, I always have to try for myself before making any kind of assumption or decision.

 

I guess bottom line for me is that I totally believe in science and scientific method but I just don't believe at this point the science is at the point where it can consistently prove or disapprove or explain what some listeners experience. This means at this point, the most reliable test has to be our own ears.

[PeterSt]

The prevalent atitude on CA seems to be that science is useless when it comes to audio. Many people seem to be convinced that audio components are somehow build by wizards with sticks and clay. And particularly DBTs are hated with a passion worthy of a better cause.

 

I don't know where you got this perception from, but I see it the other way around. In my own perception the "science" stuff is beaten to death in here, and it is only that not many seem to know really what to do and most certainly not how to judge or have some realism with real life.

If you like to compare this to Hydrogen (and of course you do) well THEN you end up with total rubbish. Hey, says me and I am pretty confident about it.

 

So it's the other way around I'm afraid; you like science but you may be the last to know what that really is. For audio I mean.

Sorry ...

[burnspbesq]

And my question is: why do you think JGH failed so miserably at steering audio in that science-based direction that he apparently values so much? Hypocrisy, helplesness, ....

 

Lack of relevance.

 

There are far too many real-world examples of devices measuring substantially identically by every metric we know how to measure and yet sounding very different in real-world use. The only logically sound conclusion that can be drawn from these experiences is that we're not measuring the things that are causing the differences. Perhaps in the future we will figure out what those things are and figure out how to measure them, but for now, measurement seems to be superfluous.

 

Similarly, with respect to double-blind testing, my view has always been that since that's not how I listen in real life, the process is unlikely to tell me anything useful about whether I will prefer component A to component B (or vice versa) in real life. Add to that the fairly obvious problems of agenda effects and Hawthorne effect, and WADR, I'm just not seeing a case for double-blind testing.

[PeterSt]

So it's the other way around I'm afraid; you like science but you may be the last to know what that really is. For audio I mean.

Sorry ...

 

OK, there was no need to get personal. So apologies.

[Ajax]

Trithio,

 

I have actually enjoyed some (not all) of your contentious posts in the past. I think we all need our views to be challenged to grow. However, in your (desperate?) need to be noticed you consciously antagonise and for me it is getting really boring. Your most recent example posted above:

 

"And my question is: why do you think JGH failed so miserably at steering audio in that science-based direction that he apparently values so much? Hypocrisy, helplessness, ...."

 

Attacking a recently departed icon of the industry and implying he is a hypocrite while he is obviously no longer here to defend himself is a low blow that I personally cannot stomach. Please tell me that I have not interpreted you correctly.

 

However, your other inflammatory comments are pretty clear.

 

"The prevalent attitude on CA seems to be that science is useless when it comes to audio. Many people seem to be convinced that audio components are somehow build by wizards with sticks and clay. And particularly DBTs are hated with a passion worthy of a better cause."

 

So there is no confusion I am a civil engineer and many years ago I spent 5 years studying engineering, statics, dynamics, metallurgy, geology, applied maths etc etc and then applied what I learnt in the the real world where if you get it wrong things things fall down and they kill people. But guess what ... we use to base our designs on structures being rigid but then found that under load they became fluid and could actually withstand greater dead loads before failure. We also learnt the opposite .... that they could withstand very little live load if applied in a certain way ... look up the failure of bridges in Wikipedia and in particular the failure of the Tacoma bridge and West gate bridge (Melbourne).

 

List of bridge failures - Wikipedia, the free encyclopedia

 

The point is we are continually learning and if people experience phenomena that cannot readily be explained by the current level of science it does not readily follow that they are idiots or don't value science - it may well be that the science is not yet up to speed, particularly in an industry in its infancy such as CA.

 

IMO the majority of members at CA are here to educate and learn while enjoying the camaraderie of like minded individuals and their common love for music.

 

We are simply sharing our experiences and knowledge. You on the other hand are continually spoiling for a fight with your inflammatory comments.

 

What are your real intentions? What motivates you .. why are you so needy to be noticed?

[mmerrill99]

Trithio, the problem as I see it is that what you are talking about is often pseudo-science. Measurements that have very little correlation to the issue (auditory perception) & tests that fail to be rigorous enough to draw any conclusions from the results (DBTs).

 

The great difficulty in this area is that we are trying to bridge the gap between engineering & perception. The mistake made is to think that the usual approach used in engineering can be directly applied to perception. The reason our current measurements have very correlation with what we hear is because we don't know the rules of auditory perception & therefore don't know what measurements are important.

 

Have a look at David Griesinger's work in the area of auditory perception & his measurements for how we perceive "presence" in the audio stream.Look at this

from about 35:00 & see how current acoustic science has ignored some important areas & how current existing acoustic measurements are wrong.

 

So, you have to remember that "science" isn't a fixed set of theories/rules - it's an approach to explaining the real world that is observed & formulating a theory that best explains the real world. A good theory will be able do this & will also be able to predict the outcome of experiments that haven't been performed before. But all theories are only the best guess that explain the current set of observations. As new observations or new ways of looking at the problem emerge, theories are revisited & revised, if needed.

 

Now, audio DBTs, are a fine idea if run rigorously. We are dealing with auditory perception that is prone to so many influencing factors, not just sight/knowledge of the devices. Unless all these factors are controlled or accounted for, then the results cannot be trusted. A set of standards exist for how to run DBTs (designed to minimise & account for influencing factors) which are seldom adhered to.

[Paul R]

This may generate some controversy and I would apreciate if everyone forgot about trithio and posted to the subject.

The prevalent atitude on CA seems to be that science is useless when it comes to audio. Many people seem to be convinced that audio components are somehow build by wizards with sticks and clay. And particularly DBTs are hated with a passion worthy of a better cause.

 

I wanted to write a post about science, DBTs and audio but then I found a perfect quote in the most surprising place: Stereophile.

 

That is JOhn Atkinson interviewing J. Gordon Holt around 2005.

 

And my question is: why do you think JGH failed so miserably at steering audio in that science-based direction that he apparently values so much? Hypocrisy, helplesness, ....

 

Well first off, you will find more scientists, mathematicians, engineers, and so forth in the CA population that you will generally find in any population save a university. And like within academia, opinions are often furiously defended.

 

Essentially, I think you have it backwards. The science gets beat to death here, more so than on any other forum - especially the gasbag forums. But as well, people recognize that something real is happening in many areas of audio, and seek to explain it, rather than dismiss it. Without the use of pseudo science.

 

When psudeoscience raises its ugly head, such as in the TAS reviews that touted "scientific" listening tests with unexpected results, it gets identified and pounced on very quickly. Harsh criticism is always forthcoming. Very finely calibrated BS detectors start quivering on people all over the forums.

 

One issue I find aggravating it is nearly impossible to insert mathematical symbology here, so everything has to be explained pretty much in English. That takes a enormous quantity of words, when a half dozen symbols can sometimes tell the whole story exactly. Just start talking about time-domain operations (i.e. convolution w/wavelets) and the Nyqvist-Shannon crowd comes down on you with nothing but frequency analysis. (*sigh*)

 

And in specific to JGH - you do know that Stereophile is, to the best of my knowledge, the *only* publication that runs consistent and informative tests on all equipment that they review. Moreover, they have built up a nice huge database of test results on that equipment. I would seriously consider that as holding up and supporting the values of JGH, not failing at it in any way.

 

Point in case is that often you will get a reviewer saying he likes the sound of some piece of gear that tests out as seriously flawed. The reviewer then often gets the opportunity to discuss the issues. Or even more often, a reviewer will comment that this or that piece of gear has a hump or dip in its frequency response around xxxhz, which subsequent testing then almost always backs up with hard data.

 

-Paul

[esldude]

Not sure how quoting the opinion publicly stated by a departed person is wrong as one poster suggested in regards to JGH. Calling it an attack upon that departed person when he can't defend himself. Do note the OP didn't call him a hypocrite, he just wondered what you consider such an opinion, and where it came from. Obviously he can no longer ask the person who made the comments (JGH).

 

Well in any case here is a little bit more on the topic by JGH, 15 years after those above quoted comments. Taken from a post on another forum. Doesn't appear he changed his mind. By Bill Stevenson here:

Daisy BBs and other assorted nonsense - MusicPlayer Forums

 

 

Strong stuff. Fifteen years later, Gordon is comfortably retired in Boulder, Colorado. I e-mailed him Labor Day to ask him about that 1992 polemic. My questions are in italics, followed by Gordon's unexpurgated answers (footnote 2).

 

Do you still feel the high-end audio industry has lost its way in the manner you described 15 years ago?

 

Not in the same manner; there's no hope now. Audio actually used to have a goal: perfect reproduction of the sound of real music performed in a real space. That was found difficult to achieve, and it was abandoned when most music lovers, who almost never heard anything except amplified music anyway, forgot what "the real thing" had sounded like. Today, "good" sound is whatever one likes. As Art Dudley so succinctly said [in his January 2004 "Listening," see "Letters," p.9], fidelity is irrelevant to music.

 

Since the only measure of sound quality is that the listener likes it, that has pretty well put an end to audio advancement, because different people rarely agree about sound quality. Abandoning the acoustical-instrument standard, and the mindless acceptance of voodoo science, were not parts of my original vision.

 

I remember you strongly feeling back in 1992 that multichannel/surround reproduction was the only chance the industry had for getting back on course.

 

With fidelity in stagnation, spatiality was the only area of improvement left.

 

As you were so committed to surround, do you feel that the commercial failures of DVD-Audio and SACD could have been avoided?

 

I doubt it. No audio product has ever succeeded because it was better, only because it was cheaper, smaller, or easier to use. Your generation of music lovers will probably be the last that even think about fidelity.

 

Judging by online forums and by the e-mail I receive, there are currently three areas of passion for audiophiles: vinyl playback, headphone listening, and music servers. Are you surprised by this?

I find them all boring, but nothing surprises me any more.

 

Do you see any signs of future vitality in high-end audio?

Vitality? Don't make me laugh. Audio as a hobby is dying, largely by its own hand. As far as the real world is concerned, high-end audio lost its credibility during the 1980s, when it flatly refused to submit to the kind of basic honesty controls (double-blind testing, for example) that had legitimized every other serious scientific endeavor since Pascal. [This refusal] is a source of endless derisive amusement among rational people and of perpetual embarrassment for me, because I am associated by so many people with the mess my disciples made of spreading my gospel. For the record: I never, ever claimed that measurements don't matter. What I said (and very often, at that) was, they don't always tell the whole story. Not quite the same thing.

 

Remember those loudspeaker shoot-outs we used to have during our annual writer gatherings in Santa Fe? The frequent occasions when various reviewers would repeatedly choose the same loudspeaker as their favorite (or least-favorite) model? That was all the proof needed that [blind] testing does work, aside from the fact that it's (still) the only honest kind. It also suggested that simple ear training, with DBT confirmation, could have built the kind of listening confidence among talented reviewers that might have made a world of difference in the outcome of high-end audio.

 

Yet you achieved so much, Gordon.

 

I know I did, and my whole excuse for it—a love for the sound of live classical music—lost its relevance in the US within 10 years. I was done in by time, history, and the most spoiled, destructive generation of irresponsible brats the world has ever seen. (I refer, of course, to the Boomers.)

[blaven]

Just to be clear double-blind testing and measurements are two entirely different things that can exist on their own.

 

In Audio, one can certainly have DBT without objective measures. The problem might be, that you would need a larger sample size to reach a statistically significant conclusion (particularly if the difference experienced is less easy to detect)

 

Regarding measurements-I would love to see them in things such as cables. That being said, even if two cables measured differently, that would not define which one some of us would think as a "better cable"... And, if they measured differently, that does not mean that we can actually hear or detect the difference without an über sensitive measuring device.

 

It still would be helpful to have measurements, and subjective testing, and occasionally double-blind testing. Certainly some, or all can be applied depending upon what the goal of the reviewer is.

[PeterSt]

A different response from my hand : me.

 

It is just impossible to NOT hear something in the B round you heard in the A one. Only the other way around might work but even then, one time only. And then still you will be in doubt because possibly your attention went to the "thing" in particular just because your attention was elsewhere the previous round (why always listen to the same ? - I can't just because you watched for "that" already).

 

So as you know (from another thread) I can only do it by listening for 5 days in a row to the "B" situation. And after that it doesn't require "A" because A I was used previously for a longer time already. And thus I imply also that only when you know the whatever system for a longer time, you can compare with something new.

 

And you know, I *do* progress. And more fast than anyone else anywhere, I dare say. You'll have no clue.

Ehm, amen.

[mmerrill99]

A different response from my hand : me.

 

It is just impossible to NOT hear something in the B round you heard in the A one. Only the other way around might work but even then, one time only. And then still you will be in doubt because possibly your attention went to the "thing" in particular just because your attention was elsewhere the previous round (why always listen to the same ? - I can't just because you watched for "that" already).

 

So as you know (from another thread) I can only do it by listening for 5 days in a row to the "B" situation. And after that it doesn't require "A" because A I was used previously for a longer time already. And thus I imply also that only when you know the whatever system for a longer time, you can compare with something new.

 

And you know, I *do* progress. And more fast than anyone else anywhere, I dare say. You'll have no clue.

Ehm, amen.

I agree, Peter! Quick A/B testing is very error prone - long term listening is the more reliable way.

[esldude]

To the OP, trithio,

 

Well, you can see the typical course taken on CA. People will tell you of firm results comparing A to B. Of course they most often will mean they listened to A and then to B knowing which was which the whole time. If you ask for it done blind, they demur, say blind listening doesn't work. Will hold their sighted listening beyond bias due to experience and honesty. If blind results dispute sighted results then the blind test must be wrong, because they trust their ears. Never mind that measurements show zip, genuine science predicts zip, and the principles of science and engineering that work to design and produce the equipment somehow fail at predicting results. Even if all those agree and are tested to agree. And blind testing shows the same lack of results. None of that matters because an audiophile somewhere heard something. It really is silly isn't it?

[esldude]

I agree, Peter! Quick A/B testing is very error prone - long term listening is the more reliable way.

 

I do not agree. Quick testing is the most revealing of the smallest differences. Long term listening obscures real differences and tremendously increases the liklihood of other factors influencing the conclusions.

 

Further Peter's description is a bit misleading. The problem of A vs B one time has some real validity. But you can switch from A to B back and forth however many times you want to do so. You aren't limited to one shot each. Doing so every 5 days will take you awhile though.

[Paul R]

To the OP, trithio,

 

Well, you can see the typical course taken on CA. People will tell you of firm results comparing A to B. Of course they most often will mean they listened to A and then to B knowing which was which the whole time. If you ask for it done blind, they demur, say blind listening doesn't work. Will hold their sighted listening beyond bias due to experience and honesty. If blind results dispute sighted results then the blind test must be wrong, because they trust their ears. Never mind that measurements show zip, genuine science predicts zip, and the principles of science and engineering that work to design and produce the equipment somehow fail at predicting results. Even if all those agree and are tested to agree. And blind testing shows the same lack of results. None of that matters because an audiophile somewhere heard something. It really is silly isn't it?

 

To Dennis -

 

Of course, the reverse of that doesn't make any sense either. People will tell you of firm results saying you can't possible hear what you so clearly heard, because someone else taking a blind test can't hear it. Duh...

[esldude]

To Dennis -

 

Of course, the reverse of that doesn't make any sense either. People will tell you of firm results saying you can't possible hear what you so clearly heard, because someone else taking a blind test can't hear it. Duh...

 

People hear lots of things that aren't different due to the soundwaves reaching their eardrums. If the difference is really due to different soundwaves, they also could hear them blind. When they can't, you know something else was responsible for what they heard other than the soundwaves at the eardrum. To equate sighted hearing as equivalent data to blind hearing is a false equivalence.

[Paul R]

People hear lots of things that aren't different due to the soundwaves reaching their eardrums. If the difference is really due to different soundwaves, they also could hear them blind.

 

What makes you assume that? Do people only hear things differently because of the sound waves reaching their eardrums, or do different people hear things differently when the same sound waves reach their eardrums? That is not really a trick question, but the answer is the second. People can hear (perceive) the same stimuli differently, and that includes sound.

 

As for hearing them "blind", meaning without knowing what they are listening to, that is a fairly reasonable assumption, but I think you will find that people perform just about as poorly in blind studies where people *should* have been able to hear a difference as when the signal should have been inaudible. That leads to some interesting questions now, don't it?

 

When they can't, you know something else was responsible for what they heard other than the soundwaves at the eardrum. To equate sighted hearing as equivalent data to blind hearing is a false equivalence.

 

Since the first assumption is not valid, the conclusions drawn upon it are also questionable.

[esldude]

What makes you assume that? Do people only hear things differently because of the sound waves reaching their eardrums, or do different people hear things differently when the same sound waves reach their eardrums? That is not really a trick question, but the answer is the second. People can hear (perceive) the same stimuli differently, and that includes sound.

 

As for hearing them "blind", meaning without knowing what they are listening to, that is a fairly reasonable assumption, but I think you will find that people perform just about as poorly in blind studies where people *should* have been able to hear a difference as when the signal should have been inaudible. That leads to some interesting questions now, don't it?

 

 

 

Since the first assumption is not valid, the conclusions drawn upon it are also questionable.

 

It is not an assumption. People will regularly report a sound difference when the same sound over the same equipment is repeated.

 

Now changing apples to alligator tomatoes, do different people hear the same sound differently doesn't mean very much does it.

 

And unfortunately for your strange argument, no we don't find people do about as poorly when they should have heard a signal blind as when it should be an inaudible difference. That is the very basis of the testing is it not. Blind results are reliably repeatable for genuinely audible differences. The list of such differences diverges from the list of things audiophiles think they hear quite severely.

[PeterSt]

Anyway that is what I, personally, mean with the science in here. Blablablablabla and even more of it. There's no f*ing realism in anything that I can see.

 

psychologicalwarfare.com, that's what this forum should be renamed to. And you know what ? the domain is still free.

 

Don't you notice that every single thread ends up with this ? and when one is finished, one defines a poll and there we go again. Not that I blame trithio for that because how could he know.

JGH was right.

 

Now please continue.

[gmgraves]

This may generate some controversy and I would apreciate if everyone forgot about trithio and posted to the subject.

The prevalent atitude on CA seems to be that science is useless when it comes to audio. Many people seem to be convinced that audio components are somehow build by wizards with sticks and clay. And particularly DBTs are hated with a passion worthy of a better cause.

 

I wanted to write a post about science, DBTs and audio but then I found a perfect quote in the most surprising place: Stereophile.

 

That is JOhn Atkinson interviewing J. Gordon Holt around 2005.

 

And my question is: why do you think JGH failed so miserably at steering audio in that science-based direction that he apparently values so much? Hypocrisy, helplesness, ....

 

 

Since JGH was one of my closest friends, I feel somewhat qualified to answer that. When Gordon was a big influence on the audio scene, Stereophile was a tiny magazine with a small circulation. Gordon was not a great businessman and he had a problem with keeping to a publication schedule. Also, he was a one-man show. He did most of the reviewing, layed-out the magazine single-handedly and paid for each issue out of pocket. His late issues were legendary. Harry Pearson used to say that he started TAS in an effort to force Gordon to publish on time. It didn't work.

 

When, in 1982, Larry Archibald (a wealthy Santa Fe high-end car repair shop owner and audio enthusiast) bought Stereophile, it was with the idea of putting it on a steady business and financial footing. Originally, the idea was that Larry would hire people to run the "front office" leaving Gordon to manage putting the magazine together. More reviewers were hired (including Your's Truly) and more factotum-type support personnel were hired as well. Eventually John Atkinson was hired away from the editorship of Britain's prestigious Hi-Fi News and Record Review to be the Editor-in-Chief of Stereophile. What I watched happen is that with each change, the magazine got bigger (a good thing) and Gordon's power and influence over the magazine's editorial policy became less and less (not a good thing), until, at last he became first, merely a figurehead (Stereophile's motto in those days was "JGH, In who's ears we trust") and then finally, Editor Emeritus, who had no power at the magazine at all. He just did an occasional review after that. In the mid-nineties, Gordon even moved away from Santa Fe to Boulder Colorado severing his relationship with Stereophile altogether in 1999.

 

So you see, even though Gordon was the father of subjective reviewing, and was almost lionized by the audio community, he never really had that much power. And by the time Stereophile became big enough to influence the industry, so was TAS, and Stereophile was no longer in Gordon's hands.

[sdolezalek]

For those of you who strongly believe in DBT, what are the things, in your opinion (or even better what does the data show), that people can distinguish between?

 

I am assuming that you generally believe: (a) that there is no audible difference between cables (power, speaker, USB, ethernet, etc.); (b) that there is no audible difference between 16/44 and hi-res files; and © that there is no audible difference between amplifiers (unless the specifications are really different). I also assume (or maybe hope) that you will acknowledge that there are DBT verifiable differences between speakers?

 

Just trying to figure out whether there is ANY common ground here. Part of me would love to believe the DBTers are right because it would save a LOT of money on stuff that makers no difference.

[esldude]

For those of you who strongly believe in DBT, what are the things, in your opinion (or even better what does the data show), that people can distinguish between?

 

I am assuming that you generally believe: (a) that there is no audible difference between cables (power, speaker, USB, ethernet, etc.); (b) that there is no audible difference between 16/44 and hi-res files; and © that there is no audible difference between amplifiers (unless the specifications are really different). I also assume (or maybe hope) that you will acknowledge that there are DBT verifiable differences between speakers?

 

Just trying to figure out whether there is ANY common ground here. Part of me would love to believe the DBTers are right because it would save a LOT of money on stuff that makers no difference.

 

Good question.

 

Level differences of .2 db are reliably detected. Which is why any non-leveled matched comparison is suspect. The louder audio signal is perceived as better. It is also why long term listening is suspect. Frequency response abberattions not much larger in level if they cover broad areas like a couple octaves are also detected. So certainly speakers are detected. Harman does blind speaker testing with speakers behind a curtain and a mechanism that can swap speakers in only 3 seconds to swap back and forth.

 

Distortion if above .1% can be detected though only with test signals. For music the number is more like 1% though the amount varies with the complexity of the music. Contrary to many expectations the more complex the higher the percent distortion before it is noticed.

 

Jitter is a more variable thing and data show it is detectable at perhaps a few nanoseconds for some types, though several times that much for other types. And experimental data is a bit sketchy on that. It also likely varies with the complexity of the signal.

 

Right off the top of my head that is a start. There are more complex things like masking effects though they don't get talked about all that much on forums.

[Paul R]

It is not an assumption. People will regularly report a sound difference when the same sound over the same equipment is repeated.

 

Now changing apples to alligator tomatoes, do different people hear the same sound differently doesn't mean very much does it.

 

And unfortunately for your strange argument, no we don't find people do about as poorly when they should have heard a signal blind as when it should be an inaudible difference. That is the very basis of the testing is it not. Blind results are reliably repeatable for genuinely audible differences. The list of such differences diverges from the list of things audiophiles think they hear quite severely.

 

It is absolutely an assumption. And a very incorrect one at that.

 

Not everyone will report a difference, and test subjects will report different differences.

 

And bull corn - we absolutely do find people do just as poorly when people should have heard an audible signal as when it should be inaudible. Ever trained acoustic sensor operators? I have. They miss really common stuff all the time, until they are trained to be able to hear and discern what they should hear.

 

There you go again, claiming competence you do not have like a full fledged authority.

[mmerrill99]

I do not agree. Quick testing is the most revealing of the smallest differences. Long term listening obscures real differences and tremendously increases the liklihood of other factors influencing the conclusions.

 

Further Peter's description is a bit misleading. The problem of A vs B one time has some real validity. But you can switch from A to B back and forth however many times you want to do so. You aren't limited to one shot each. Doing so every 5 days will take you awhile though.

This isn't QUICk A/B testing then, is it? The premise of quick A/B testing is the unreliability of audio memory & how we can only retain what we just heard for about 4 seconds which then allows us, supposedly, to compare to the next piece in this time frame - as you say "the most revealing" So why are you now ignoring this premise & the supposed strength of quick A/B testing to suggest that it can be used for long term testing? What exactly are you saying?

[mmerrill99]

What makes you assume that? Do people only hear things differently because of the sound waves reaching their eardrums, or do different people hear things differently when the same sound waves reach their eardrums? That is not really a trick question, but the answer is the second. People can hear (perceive) the same stimuli differently, and that includes sound.

 

As for hearing them "blind", meaning without knowing what they are listening to, that is a fairly reasonable assumption, but I think you will find that people perform just about as poorly in blind studies where people *should* have been able to hear a difference as when the signal should have been inaudible. That leads to some interesting questions now, don't it?

Yes & there is usually no internal controls for false negatives included in such blind tests - a recommendation that ITU & MUSHRA standards make for all such testing. Having such statistics for false negatives within blind tests would certainly be interesting but it's like asking turkeys to vote for Thanksgiving.

 

Blind tests that don't have such reporting of false negatives logically must be disregarded.