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Testing audiophile claims and myths - Page 140

post #2086 of 3043

Well, let's say a guy gets a new shiny USB cable, installs it and suddenly his whole system sounds better. Measurements show the cable is identical to the old, cheap one.

 

the new USB cable performing no better = placebo

hearing an improvement = placebo effect

post #2087 of 3043
Quote:
Originally Posted by xnor View Post

Well, let's say a guy gets a new shiny USB cable, installs it and suddenly his whole system sounds better. Measurements show the cable is identical to the old, cheap one.

 

the new USB cable performing no better = placebo

hearing an improvement = placebo effect

I think the argument is that expensive USB cables cannot be called a placebo because there is no scientific evidence that the health of the owner improves upon purchase. wink_face.gif

 

Cheers 

post #2088 of 3043
Quote:
Originally Posted by ab initio View Post

I think the argument is that expensive USB cables cannot be called a placebo because there is no scientific evidence that the health of the owner improves upon purchase. wink_face.gif

 

Cheers 


Ah, but what about the health of the seller? 

post #2089 of 3043
Quote:
Originally Posted by Wizz View Post

In this debate, something that bothers me somewhat, it's the use of the word "placebo" when dealing with audio perceptions that can't be measured or proven.

 

The placebo effect originally refers to a phenomenon that is, actually, measurable and provable. A patient takes a pill that is supposed to have no effect, but gets better nonetheless. The improvement is measurable (regression of symptoms - like fever, for instance) and sometimes -actually rather often- the "false" pill does better than the real one.

 

To me "placebo" is a term that doesn't fit these audio illusions, since they can't be measured. They're not real... the original placebo effect, on the other hand, causes real, actual, measurable improvements in the patient.

 

What we're dealing with in audio is, in my view much closer to hallucinations, where the brain creates "logical" patterns causing the senses to see, feel, taste or hear things that aren't actually there (at least not in the form we think we sense them). More close to optical illusions, as well. They have been discussed here btw, its a great way to remind people that we should NOT trust our senses, because our senses play tricks on us all the time.

 

Just curious, has anyone here already played a game that I love, which is to concentrate (kind of) on audio noise (pink noise for instance) until actually hearing in it voices, melodies, chords, even a full orchestra? I do that often when taking a shower. It's fun, and rather easy if you have a bit of imagination. I know other people, musicians or not, who play that game too. Sometimes, the illusion can even get pretty uncanny! It's a bit like looking at video noise (like we could with old TV programs...) and seing movement in it. We sure see these things ven though they aren't there per se.

Subjective differences or actual therapeutic effects fall under the placebo category so I think the word placebo is suitable for audio.

post #2090 of 3043
Quote:
Originally Posted by ab initio View Post

I think the argument is that expensive USB cables cannot be called a placebo because there is no scientific evidence that the health of the owner improves upon purchase. wink_face.gif

 

Cheers 

What if the owner was deaf......before

post #2091 of 3043
Quote:
Originally Posted by Wizz View Post

 

Argumentum ad populum. Sigh. Cable believers seem to have an endless cornucopiae of fallacies ready to be thrown at the unbelievers, just as cultists do.

 

Besides, of course we can throw that aside! This is called being rational. Even, dare I say, adult. If in your book a claim (a "noticed improvement" is just that, a claim), whatever silly it is, automatically gains credibility by simply being repeated by more and more people, despite the lack of any proof, then... there is a whole lot of b*s on earth that you are bound to be taking seriously! biggrin.gif

 

Just open any tabloid: thousands of people on earth actually believe what's printed in these. By your book, because there are so many people believing in what is claimed in these, we shouldn't throw these claims aside? Pah! Count me out. tongue.gif

 

I'm not too sure about that, the main idea cable believers employ is, "just listen to it" ie. build a transparent system and compare by ear (or visit someone with a transparent system and compare on their system).  There really isn't that much to it in terms of wild theories and justifications, in fact theory and/or measurement seems to be the preoccupation mainly in this subforum.  No endless cornucopiae of fallacies is or should be required, similarly, no fruitles or unreasonable "burden of evidence" to prove to someone else that you are hearing something with your own ears.  Opinions are offered without promise of universal validity, repeatability etc.  Caveats such as YMMV, IMO, in my system, to my ears ensure that these limits are established.  Opinions can be taken or ignored without unreasonable demands or assurances.  This is what allows normal discussions to take place outside this subforum.

post #2092 of 3043
Quote:
Originally Posted by drez View Post

 

I'm not too sure about that, the main idea cable believers employ is, "just listen to it" ie. build a transparent system and compare by ear (or visit someone with a transparent system and compare on their system).  There really isn't that much to it in terms of wild theories and justifications, in fact theory and/or measurement seems to be the preoccupation mainly in this subforum.  No endless cornucopiae of fallacies is or should be required, similarly, no fruitles or unreasonable "burden of evidence" to prove to someone else that you are hearing something with your own ears.  Opinions are offered without promise of universal validity, repeatability etc.  Caveats such as YMMV, IMO, in my system, to my ears ensure that these limits are established.  Opinions can be taken or ignored without unreasonable demands or assurances.  This is what allows normal discussions to take place outside this subforum.

Actually, the biggest issue is a total disregard of facts and the total embrace of snake oil. The biggest put down is if you do not own the XYZ cable, you're not allowed to state your facts or opinions. Secondly, all facts are ignored. The argument always goes ;"there is no scientific theory yet or there is no measurement. In any industry you cannot do that. If you are a cook and you don't know the recipe....

 

"Oh yes this tasted real good."

"What is it?"

"I don't know, I just picked it up from the backyard. It doesn't look like anything I've ever seen. I must have just invented it! Yeah!"

 

This stuff just won't fly in the real world. If you believe in cable, I got this car I can sell to you and it can go from 0 to 100 in 2 sec. Oh wait, I meant this car will go really really fast. You'll need to buy it and try it..... Ah, test drive is not going to work because it needs 200 hours of burn in.

 

" What do you mean the car is not fast? Do you have the burn in? Mmm... Do you have the racing strip? Hmmm... The road you're driving on probably does not have high enough resolution. Argg... You know sir. You don't know how to drive. And if you want to return the car there is an 100% restocking fee after 100 hr of use"

 

Welcome to the real world.

post #2093 of 3043
Quote:
Originally Posted by drez View Post

 

I'm not too sure about that, the main idea cable believers employ is, "just listen to it" ie. build a transparent system and compare by ear (or visit someone with a transparent system and compare on their system).  There really isn't that much to it in terms of wild theories and justifications, in fact theory and/or measurement seems to be the preoccupation mainly in this subforum.  No endless cornucopiae of fallacies is or should be required, similarly, no fruitles or unreasonable "burden of evidence" to prove to someone else that you are hearing something with your own ears.  Opinions are offered without promise of universal validity, repeatability etc.  Caveats such as YMMV, IMO, in my system, to my ears ensure that these limits are established.  Opinions can be taken or ignored without unreasonable demands or assurances.  This is what allows normal discussions to take place outside this subforum.


"Just listen to it," but only in the context of sighted, non-controlled listening evaluations.  Throw in controls and not knowing what you are listening to and everything turns into a shambles.  Indeed on this web site you are not even allowed to raise the issue of a double blind test in some of the forums.  The human condition is as good as it gets for any of us, but the human itself is a highly imperfect measurement device.

 

"There really isn't that much to in terms of wild theories and justifications..."  Are you being serious here?  From what I've read cable peddlers and their defenders make pretty much nothing but wild theories and justifications.   

 

"No fruitles or unreasonable "burden of evidence to prove to someone else..."  If someone is making a claim, e.g. these two visibly different but electrically identical cables sound "night and day" different shouldn't the burden be on the claimant to back up the claim?  

 

"This is what allows normal discussions to take place outside this subforum."  So far as I can tell, normal discussions take place in this forum too.  What's wrong with having a subforum that has a different tenor than all the other ones?  Isn't variety the spice of life?  I'm sure you're very welcome to post here, but if you are not comfortable with the discussions here why not seek out a spot more to your liking?   

post #2094 of 3043

My point is that speculation based off of other data points is still speculation, and that it is not reasonable to demand evidence or proof from people when they are stating an opinion.  In many cases, this is speculation based off data which is outdated, or not up to academic research standards.  There are already some single blind tests that challenge some of the cable myth claims, but these are met with harsh criticism over methodological weaknesses.  Sorry I can't be bothered to provide all the links at this point in time, but one (probably double blind, I have not read the paper myself) I have come across is the jitter audibility numbers which used to be thrown around, where more recent studies by Julian Dunn have revised the threshold down to 15-20ps.  let's face it most double blind tests are set up by audio skeptics who have a vested interest in not making fools of themselves by discrediting the what they have been claiming for years.  Double blind testing methodologies are difficult to set up, time consuming, and prone to produce null results.  Clearly it is not reasonable to expect everyone discussing hifi components to go to this level of trouble, especially when the likely result will not provide any useful data for the discussion.


Edited by drez - 8/4/13 at 1:00am
post #2095 of 3043
Quote:
Originally Posted by drez View Post

where more recent studies by Julian Dunn have revised the threshold down to 15-20ps.

 

That is a theoretical estimate for a completely unrealistic worst case scenario. Do you listen to ultrasonic pure tones at ridiculously high SPL in a perfectly silent room, with jitter that is deliberately designed to produce a sideband at the frequency human hearing is most sensitive to ? If not, you can safely disregard this threshold for music listening under realistic conditions. It is also possible to simulate various types of jitter with software, and in fact I already did so on this forum, but apparently no one was confident of being golden eared enough to try to ABX the samples, which had very high amounts of jitter, by the way.

 

Quote:
Originally Posted by drez View Post

Double blind testing methodologies are difficult to set up, time consuming, and prone to produce null results.  Clearly it is not reasonable to expect everyone discussing hifi components to go to this level of trouble, especially when the likely result will not provide any useful data for the discussion.

 

Therefore, we should just accept the results of non-blind (and usually not even level matched) testing as fact, even though it is almost guaranteed to produce false positives ?

post #2096 of 3043
Quote:
Originally Posted by drez View Post

Double blind testing methodologies are difficult to set up, time consuming, and prone to produce null results.  Clearly it is not reasonable to expect everyone discussing hifi components to go to this level of trouble, especially when the likely result will not provide any useful data for the discussion.

Yeah, life's tough.  But if you want real data you have to do real scientific tests with controls, and remove as many biases as possible.  No, you can't expect everyone to actually perform double-blind tests on everything they discuss, but to actually favor uncontrolled, bias-laden "tests" (read:opinions) over scientific tests methodologies because they produce the data you like is putting your trust and belief in something rather inauthentic. DBT do produce accurate data.  Sometimes so-called "null results" are exactly that: accurate data.

 

And with that, I submit my post #1000.  I now take a deep breath and wonder why.

post #2097 of 3043
Quote:
Originally Posted by drez View Post

Double blind testing methodologies are difficult to set up, time consuming, and prone to produce null results.  Clearly it is not reasonable to expect everyone discussing hifi components to go to this level of trouble, especially when the likely result will not provide any useful data for the discussion.

Most members on head-fi will go to ludicrous lengths to attain 'sonic nirvana'. I think DBT data is the best educational source as well as being the best determinant to achieve this. 

post #2098 of 3043

I wouldn't accept any opinion as fact, doing so is a big mistake, but this is a fairly obvious distinction, and my point was that in most cases opinion is a better basis for discussion than simulated or extrapolated predictions.  I guess I kind of contradicted myself by referring to data and scientific theory in order to support my argument, so that's probably not ideal and not to the point I was trying to make, and probably supports BlindInOneEar's argument more than my own.

 

In this subforum evidence based discussion is the norm, and I guess a bit of mockery of how foolish the rest of the audiophile community is is to be expected.  I guess my point was that skepticism is fine and all for saving money not buying "snake oil" but consider for a moment that this information cannot provide some kind of perfect prediction for how all components will perform, and that in some cases might overlook certain variables and mechanisms affecting performance.  Put it this way, a lot of what I have read regarding cables doesn't match my own experience, and if you can think of a double blind test that can compare SPDIF cables of different lengths (not saying that there is an ideal, jus that they sound different in my experience) without adding anything to the signal chain, and without any wasted time or effort from myself being put in, I'm sure someone who has already ignored the sound science knowledge and drunk the kool aid will be willing to spend their time to prove what is already considered common knowledge outside of this subforum.

post #2099 of 3043
Quote:
Originally Posted by drez View Post

and my point was that in most cases opinion is a better basis for discussion than simulated or extrapolated predictions.

 

I would hardly consider popular opinion on internet forums as a reliable basis for discussion. Especially when all those who share the opinion are also affected by the same well known and proven psychological and psycho-acoustical effects. If you asked 10 people about this image, they would probably give the wrong answer, unless they already know about the illusion. Does that make their opinion fact, or just confirm that their perception is affected by bias ?

 

Quote:
Originally Posted by drez View Post
Put it this way, a lot of what I have read regarding cables doesn't match my own experience, and if you can think of a double blind test that can compare SPDIF cables of different lengths (not saying that there is an ideal, jus that they sound different in my experience) without adding anything to the signal chain, and without any wasted time or effort from myself being put in, I'm sure someone who has already ignored the sound science knowledge and drunk the kool aid will be willing to spend their time to prove what is already considered common knowledge outside of this subforum.

 

Under those conditions, it can never be proven that a difference does not exist, just like it cannot be proven that alien abduction does not happen. Audiophiles trust sighted testing (even though it has been proven to be prone to showing differences that do not exist, like when comparing an amplifier to itself without knowing about it), and look for every possible excuse to invalidate DBT. But is it really worth obsessing so much about a very low chance that the cable makes a difference that is in most likelihood miniscule at best anyway ?


Edited by stv014 - 8/4/13 at 2:34am
post #2100 of 3043
Quote:
Originally Posted by stv014 View Post ... It is also possible to simulate various types of jitter with software ...

 

I've been thinking... (somebody stop me, before I think again... :) )  I'm interested in what your thoughts are on the following points:

1 - I assume that you apply the "jitter" by altering the values of succesive samples. Theoretically, this may generate components outside the Nyquist bandwidth. Do you filter the results before writing the output file?  "Real jitter" also generates components outside the Nyquist bandwidth.

2 - Does applying "x ns" of simulated jitter result in the same output after the reconstruction filter as "x ns" of actual DAC clock jitter would? It seems logical, and I intend to "do the math". 

3 - The jitter that matters is the jitter in the final clock that clocks the samples into the analog reconstruction stage. Jitter before this point is irrelevant so long as it is less than half a sample period.

4 - All modern DACs oversample. Given point 3 above, is it valid to consider the effects of jitter at x1 sampling rate? In an 8x oversampling DAC, the critical clock is also running at 8x the sample rate...

5 - I don't think it's possible to generate simulated jitter that accurately simulates the effect of jitter of an oversampled DAC clock.


Edited by Don Hills - 8/4/13 at 2:38am
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