Null test of analog interconnects

[sandyk]

"I would turn statistical and point to a spot on a curve that says your finding the ghost is unlikely."

Prufrock
Try telling that to the staff of Concord Repatriation Hospital in Sydney Australia , especially on the night shift,
where even elderly patients sometimes talk about the late night visitor. My daughter inlaw wasn't aware of any this stuff until she recently started nursing there, and felt very uneasy late at night, and had an elderly woman patient talk about the visitor and the clothing she was wearing. I found this link after she told me of her experience.
Seems that medical science, that you continually keep equating to audio experiences, can't disprove ghosts either. (Grin)


http://www.concordheritage.asn.au/pd...ive/200705.pdf

[bdiament]

Hi prufrock,

...Barry, at the risk of sounding like someone who continually ups the ante, the testing you have done is just blind, not double blind...

The point is, my tests are designed to convince *me*, one way or the other.
They are not designed to convince anyone else.

Further, the fact that my assistant is looking at the screen and can tell what he's switched to has zero impact on whether or not I have any clues aside from what is coming from the speakers. If I had any doubts, I'd find another way to test.

I also differ with you on what science has to say.
I understand you see and perhaps hear it differently.

By the way, set up a test I approve, pay me for my time and I'll gladly take you up on your 10:1 odds. Bring cash. ;-}

Best regards,
Barry
Soundkeeper Recordings
Barry Diament Audio

[spdif-usb]

After I've asserted what I believe I'm hearing, he does some rapid switching so I can "count" the switches. Then I listen some more.

Rapid switching actually often breaks the test.

Human hearing is non-linear on lots of levels, and because we have memory, we can never perform the same test twice. If a better system lets you hear an instrument you hadn’t noticed before, for example, you can go back to a lower-quality system and will always hear that instrument.

Robert: That brings to mind a conversation we had at CES about why blind listening tests may not be reliable. You said that when exposed to sound, our brain builds a model over time of what’s creating that sound. The rapid switching in blind testing doesn’t allow that natural process to occur, and we get confused.

Bob: That’s right. Perception happens on lots of different time scales. There’s something called the conscious present, which is a period of time over which some of this integration into an object would happen. If you were dropped into a concert hall, how long would it take you to really understand what it is you’re hearing? It can take several seconds, or even minutes, before you’re listening fully into the space.

Sometimes when you’re looking for a difference between A and B, you can hear it quickly. Other times the difference between A and B can come on a time scale of minutes or even longer where you find that you’ve changed something and you don’t notice a change but find that you have a very different connection to the music. But if you are doing quick switching that mechanism gets broken.

The problem with A/B switching, or blind listening tests, is that it doesn’t always eliminate things that we find to be important on a lot of time scales. Obviously you can do blind listening on long time scales, and that’s good. I don’t tend to do a lot of that, because typically what we’re trying to do is work out whether something we’re doing has made a difference rather than to prove that you can hear it.

Listening is so multi-dimensional. It’s always struck me as quite interesting that I can take a system where the speaker has certain, even gross, defects and maybe an amplifier has others, but we can change something very subtle in the digital signal processing that’s feeding that chain and we hear it very clearly because this difference is on a totally different dimension than all the other defects. It’s separated and independent, whether it’s spatially or whatever it is. We go into listening tests to decide when we stop hearing a distortion rather than just arbitrarily playing one thing and another thing with no knowledge of what’s going on. What we’re looking for is not only that we can hear a difference but also that it is more musically satisfying. Did it take me closer to the artist? Does it inform me more of what the composer intended? Am I able to tell better what the instruments are? You can’t always do that if you’re not somehow in control of the parameters. Do you agree?

Source: TAS 194: Meridian Audio's Bob Stuart Talks with Robert Harley | AVguide

[bdiament]

Hi spdif-usb,

Rapid switching actually often breaks the test...

?
The rapid switching is not done during listening evaluations. It only comes in after I've declared what I'm hearing is "A" or "B". At that point, any switch to the other will tell me it is the other. When my assistant does it rapidly, no counting is possible hence, wherever he "lands" is once again unknown to me. Then I start listening again, telling my assistant when to switch.

Perhaps it is a "you had to be there".
In the end, it matters only to me.

Best regards,
Barry
Soundkeeper Recordings
Barry Diament Audio

[Jud]

It might help to dilute the view the wider community has of audiophilia as well. You know,half deaf SOB's listening for phantoms that no one else hears

This has really puzzled me the several times I've seen it.

I have a buddy whose hobby is drag racing. You need to spend into the tens or even hundreds of thousands of dollars to have a competitive car even in the lower-level class that he's running in (cars not as highly modified from stock as those you may see in any drag race you happen to catch on TV). A couple of decades ago I used to do a fair amount of scuba diving, also very expensive (plus travel costs if you live away from more interesting, pleasant sorts of dive sites). Used to do a lot of backpacking as well. Could get into some $$ for gear, though you could do it pretty cheaply if you wanted. Involved long, steep, effortful days of hiking when you could just as well be lolling on a beach somewhere.

All of these pursuits and others as well are easily subject to ridicule on many fronts. (Jerry Seinfeld had a nice line about scuba diving: "Another hobby where the object is - not dying!") But why should those who enjoy this stuff care in the least? I have enough sense not to try to cajole my wife and friends into long listening sessions. I'm not above the occasional quick demo, though - bring them in, turn "Pinball Wizard" way up on my 40-year-old LP of The Who's "Tommy," and watch their eyes go wide the first time Townshend interrupts the strumming intro with one of his trademark electric windmill chords. Or put on the Beatles' "Love" version of "Strawberry Fields," the one without all the big production of the original, and see them mist up as that voice, the one my friends and I all grew up with, is there in the room, naked and vulnerable.

It's really just the same as friends talking to me about their hobbies. As long as they don't require me to be way into it, but just show me interesting stuff, it's cool. And that's the way I treat them when I talk to them about audio. I don't think they feel I'm any crazier than they are with their own hobbies (at least not for that reason), and if they do, well so what?

[bdiament]

Hi Jud,

Well said.

I've done some backpacking myself and ultimately got some expensive gear. What it provided, in addition to the pack, tent and sleeping bag combined being lighter than any single one of those from other manufacturers, was the first time I'd woken up in the woods without feeling damp.

As with other pursuits, folks who don't engage in it and folks who haven't experienced it (and had an *appreciation* for the experience) will not understand.

I've also shared that "rush" of introducing folks to what fine gear can do. I find great beauty in watching and hearing folks reactions when they first get a real close look at Saturn's rings or the pale greens and purples in the Orion Nebula through the larger of my two telescopes. (Mostly hearing their reactions because it is quite dark at the observing location.) Having those photons land on the retina is very different from receiving photons reflected from a photograph.

And your "Strawberry Fields" story reminds me of having some colleagues, all used to studio type speakers, listen to "Here, There and Everywhere" on a system built around (the then $135,000) Infinity IRS V. There are two things I'll never forget about that day. First, one of the folks approached one of the speakers and raised his hand to touch it while looking up at its size. In my mind, I saw the scene from "2001: A Space Odyssey" where one of the apes approaches the monolith. ;-}
The second thing I'll always remember is that by the end of the song, there wasn't a dry eye in the room.

Best regards,
Barry
Soundkeeper Recordings
Barry Diament Audio

[Jud]

There are people with really good test equipment who have tested interconnects. They get vanishingly low distortion from the cables of many kinds. Right down in the noise level of testing equipment far better than I have to use. Frequency response with reasonable components far wider than needed for audio. No time domain or impulse problems that could plague an audio signal. So if people are really hearing something I am at a loss as to what it could be. A difference test means you don't have to know what it could be. It should show up if it is there. It appears within the limits of what I am using nothing or darn close to it shows up. Doesn't prove that idea. Does provide some evidence. And does narrow down considerably what it could be. Maybe some other worthwhile tests looking in another way will occur to me.

Now why do I bother if I 'hear' cables. Why not just listen and go with that? Partly because I am just a curious fellow. Partly because if multi-kilobuck cables do nothing extra I just as soon not spend money on them. Mostly because to put together a nice system rationally you would rule out what doesn't matter spending most money and effort on things that do matter. If cables are a done deal, then move onto other areas that can be improved.

All makes sense. The concerns are completely valid. And as I've noted myself before in this thread, some of the differences that engineers I admire are claiming to be significant are small enough to give me pause. It's your senses vs. your logic, and that's enough to make anyone uncomfortable. I'd just urge you to allow for the possibility that the factual premises for your logic may not be as complete as they seem - that you (not specifically you, but any of us) don't know what you don't know.

I keep wanting to go back to that Keith Johnson video (and perhaps I'll even have time today), because he talks about things like each component other than the amplifier benefiting from an isolation transformer. This raises for me the role that interconnects play in transmitting noise around the system, behavior not measured by the frequency response comparisons that null testing does.

Are factors like this the solution to the apparent conflict between your null test results and sighted listening? I don't know nearly enough to say. Perhaps as Robert Christgau's T-shirt says, it really *is* "all balls," and we're just making up these differences in our heads. But it does seem that this would run into psychological effects of extraordinary complexity - consistency of effects from listening session to listening session, among different people, the level of detail of the consistencies, preference not simply following price.... At the end, have you really simplified anything, or have you just substituted an equally or even more complex psychological explanation for a technical one? Julf's new signature has a rich irony for me - the fellow who wanted to simplify, and began with the principle that we were at the center and everything else moved in simple circles, who then had to bring in circles upon circles, and circles upon those, until he had this:

[Julf]

Julf's new signature has a rich irony for me - the fellow who wanted to simplify, and began with the principle that we were at the center and everything else moved in simple circles, who then had to bring in circles upon circles, and circles upon those, until he had this:

And that is before we get into his teachings about astrology... Yes, Ptolemy should have followed his own advice.

[spdif-usb]

The rapid switching is not done during listening evaluations. It only comes in after I've declared what I'm hearing is "A" or "B".

Alright then. Thank you for clearing that up to me.

[bdiament]

Hi spdif-usb,

You're welcome. I understand where you were coming from.

Sitting in the studio, for example and trying different EQ treatments on some mixes that come in, during the comparisons, if done too quickly (and almost always after even doing it slowly for a certain amount of time in a day), one can easily get what I refer to as "lost in A/B Land". This is a sort of listening fatigue unique to this type of endeavor. If this point is reached, no decision can be made (at least no good decision) and I know it is time for a long break.

As with any other aspect of listening, I think practice makes us better if for no other reason than we learn what to avoid. It also helps one hone their skills so decisions can be arrived at more quickly and easily.

Best regards,
Barry
Soundkeeper Recordings
Barry Diament Audio

[spdif-usb]

Sitting in the studio, for example and trying different EQ treatments on some mixes that come in, during the comparisons, if done too quickly (and almost always after even doing it slowly for a certain amount of time in a day), one can easily get what I refer to as "lost in A/B Land". This is a sort of listening fatigue unique to this type of endeavor. If this point is reached, no decision can be made (at least no good decision) and I know it is time for a long break.

Listening fatigue is usually not the culprit IMO. Instead, small differences can often not be heard during a blind listening test, simply because, during such tests, the very fact people are trying their best to hear differences is what actually keeps them from hearing any. As a result of listening specifically for differences, our perception is altered in such way it makes the differences go away, whereas listening purely for pleasure magnifies them.
Moreover, as Bob Stuart of Meridian Audio pointed out at the beginning of the part I quoted earlier, the same test cannot be performed twice because we have memory. Taking a long break does not erase that memory.
So, objective listening tests do not exist because one cannot perform a listening test without knowing the fact one is performing a listening test. This may seem a little far-fetched to some, but nevertheless it is exactly how the human brain works.

[bdiament]

Hi spdif-usb,

I believe you misunderstood me again - or once again, I didn't write it clearly.

When I'm in the studio doing what I described, I'm not listening to see *if* there is a difference. I *know* there is a difference because I deliberately created it.

Best regards,
Barry
Soundkeeper Recordings
Barry Diament Audio

[spdif-usb]

When I'm in the studio doing what I described, I'm not listening to see *if* there is a difference. I *know* there is a difference because I deliberately created it.

But when people are comparing two different analog cables, which is what this forum topic is about, they also know there is a difference because they deliberately used two different cables. Whether or not the difference is too small for said people to be able to hear it does not change the fact they know that they're performing a listening test, and this knowledge fact still affects their perception regardless.

[bdiament]

Hi spdif-usb

?!
I believe we're talking about two different things.
No problem.

Best regards,
Barry
Soundkeeper Recordings
Barry Diament Audio

[Brian A]

I find it very interesting that so many good people with good ears are willing to risk their credibility with their subjective claim that they can hear the differences between cables. These claims cannot be ignored.

The Null Test is an old test made new through the recent availability of powerful digital signal processing.

I suggest that this thread should be focused only on the Null Test and should not be focused on blind testing. This is because blind testing is a statistical analysis method, and the blind test topic has ample threads on this site and elsewhere regarding the pros and cons of using it and suggestions for sampling procedures, analysis and populations.

The Null Test, on the other hand, could be an objective test; one which can be conducted by single individuals using a scrutable methodology and with results that could be reproduced and verified by others.

I suggest that those interested in advancing the Null Test procedure presume that some types of cables DO sound different and to begin the search for the reason for the difference. The subjective claim regarding cable differences is too strong to be ignored. The breakthrough will be in identifying the characteristics of cables that make them sound different, not showing that, like all past measurements using the traditional (antiquated) analytical tools, all cables should perform the same.

Maybe this work is too much for us here. Perhaps someday, an open-minded electrical engineering graduate student, who has access to rigorous methodology and to the peer supervision needed to structure a repeatable and scientifically defensible test with make the breakthrough. No one in the past could do what many of us can do now.

No, I haven’t been drinking this evening.

[esldude]

Yeah, I agree with you. One reason I posted was this is measurement oriented rather than ABX type stuff. Further it is something other people could try with a source and one computer (plus a few adapters from Radio Shack depending on their sound card).

I know I have read papers going back at least to the 1930's using some version of this methodology. Similar results. As you state, this is made new by digital tech available now.

I just wonder if most readers appreciate how very close to identical 80 dB nulls are? I noticed the latest sample files I posted have been accessed by exactly zero people. You can take the digital source files and digitally boost one by .01 dB which so little, and you go from completely digital zero at 24 bit to a null in the range of 100 dB. You can amplify that tiny residual and hear music. But without the large amping you are not going to hear this if it were there. And this is simply a level difference. It isn't distortion or anything.

I am pretty sure the nulls I have been doing don't null out completely primarily due to level differences. When you amp them up the music you can hear, though buried in white noise, sounds full range, doesn't sound thin or fat or on its own fuzzy. I have created files with tiny imbalances of response or purposeful distortion. They don't sound so much like the original as the real results. So I have the feeling the only residuals are those tiny level differences. The other thing making me think residuals aren't from the wire is nulls from the same two wires is just about the same level and sounds the same as other cables or versus other cables. If they differed and were partly due to wire differences, then you would think a cable versus itself would have a different sound amplified sound than a cable versus a differing cable.

I guess one thing you need agreement on is how deep a null is close enough to call inaudible? Now completely utter nothingness as a result would do it. Some of these results aren't so far from that. I believe that 60 dB is not going to be heard by anyone with music. I am virtually certain 80 dB isn't. You always have someone who will say if it doesn't turn something up then it isn't measuring the right thing.

I don't know what it would not be measuring. It is true, ground currents between pieces might vary though I am not sure what wire could fix or worsen that. One could have odd components so the RCL values cause trouble. I probably am not aware of other things it could be. I have done a little bit of testing that shows some construction methods pick up hum and other noise differently though these differences are pretty far down. The answer to that is buy shielded cable of the right construction or route them more carefully.

Finally, the difference files can be listened to. I am somewhat dismayed so few have. 34 people voted in the poll. 33 people have accessed the first difference file I posted. None the other two posted files. Nearly 4000 people have viewed the thread. Probably 20 or more have responded. 190 posts so far. And so few even bothered to listen to the sounds before arguing (whether for or against).

One thing I hoped was a good many might be curious enough to do this at home. You only need a source, and one computer. I would have given tips to help folks figure it out and avoid some common pitfalls. Do this yourself and see what you think then. Don't listen to my idea or other's idea, you have it in your capability to do this for yourself. Pretty impressive results are available with a laptop or netbook.

Looking back at the Carver challenge, it was mentioned most amps only null to 48 dB channel to channel. This was awhile ago, so that may be improved these days though I am betting not by much (.1 dB between channels is close to 48 dB). He agreed with the people he challenged that if he got 70 dB nulls and they sounded the same then he had won the challenge to make his cheap SS amps sound like the state of the art tube monoblocks of the time. He didn't convince many people though he convinced the staff of Stereophile.

Finally, I have posted before of interconnect cable measurements (not nulls) done by a MIT grad student. I think it was from 1998 so not ancient history. First he modeled the cables using SPICE and Matlab. Then did the measures to a pretty high level of accuracy to see if they matched his models, and to see if there was reason for them to sound different etc. etc. It was a way to test his modeling and learn something. His models appeared to be pretty much dead on and he was left with nothing to explain that they could perform differently with most equipment.

Here is a 49 page PDF of that work if you care to read it.
http://dspace.mit.edu/bitstream/hand...5/41567257.pdf

[prufrock]

I find it very interesting that so many good people with good ears are willing to risk their credibility with their subjective claim that they can hear the differences between cables. These claims cannot be ignored.

Brian
My experience with humans and their thought processes leads me to the opposite conclusion. What you are really saying is that if enough people believe in something, then there is very likely to be substance in what they are claiming. I can list multiple human belief systems that fly in the face of that. I have on other threads mentioned Dowsing as one of these. Water Divining, as it is often called, is widespread across many cultures. If you were to ask the average man in the street if dowsing assists people to find subterranean water, I reckon at least half of the people would answer in the positive. However no dowser has ever displayed such a talent (despite confidently helping to design the experiments) and the James Randi foundation's $1million prize remains unclaimed. Ask the same questions about telepathy, psychokinesis, faith healing, crop circles, UFO's, remote viewing etc and you will get millions of replies in the affirmative. The one million bucks, however, looks as safe as ever.
And the beliefs mentioned above are only on the fringe. The are others with far more public "credibility". Take homoeopathy and acupuncture for example. Neither of these have ever performed better than a placebo in studies. If you told someone in the street that you had just been to you acupuncturist, you would be unlikely to get a funny look. It has achieved public acceptance. However, delve into the rationale of it and you will see it is based on ideas that precede the dark ages.
There are many eloquent and knowledgeable posters around here that do believe cables/interconnects make a difference despite the science indicating they do not. Unfortunately the appeal to authority doesn't always work. Aside from their specific area of knowledge, they are just as liable to be hoodwinked as the rest of us. If the measurements say nothing is happening, your odds are far better with the science than relying on human perception.

Regarding DBTs: It will always come back to these. They are not perfect but still the best tool available. The nulls show nothing is happening that matters. The believers say science is not measuring the right things and that is why nothing is showing up in the measurements and that they CAN hear a difference. However then they go on and say sorry, DBTs wont work either because it is flawed procedure unsuited to audiophilia. Bulldust. All it is is a procedure that asks listeners to identify a cable/interconnect when they cannot see it or use any other clues.

[Paul.Raulerson]

Hi Dennis -

As I and other people pointed out, the way you worded the poll was not really comfortable for most people. Including me. I was not joking when I told you to be honest I would have to check both answers. I think that more than anything else, limited the responses to your poll.

As for what you measured and documented, I am not sure how anyone could argue with it. It is, however, a paradox, because people can hear a difference between interconnects in their systems. A paradox just means we don't have one or more critical pieces of information, or we are not evaluating that information correctly. It will resolve with time.

It really comes down to an issue of either many many people are fooling themselves, with an unparalleled degree of consistency or - more likely to my way of thinking - we are simply not testing the right thing.

Let me point out that a null between the cables is great, but is there any possible operator that the cables could present that would affect the sound coming out of the speakers? Obviously, if that is true, and circumstantial evidence points to it being true, then whatever that operator is need to be identified and measured. Most likely it is going to be a rather complex interaction of things though, else it would already have been easily found and measured to the last nanometer.

Again, you did good work on this, no fooling. But - trust your ears too. If your ears and your results don't agree, then they don't agree. Take that as a fact, but put hallucination way down on the list. If you have to ask yourself if you hallucinating, then you probably are not.


As for the 1998 cable simulation - well - I have my own opinions about that. Simulating cables is hard stuff. I've been working on a speaker cable simulation for more than a year and it is not above 80% reliable yet. And at that, it cannot handle all the factors that come into play. And believe it or not, music from a digital source acts differently in a bloody speaker cable than music from an analog source. Don't ask me why, because every theory I have right now is as loose as ashes...

-Paul

[ringenesherre]

I find it very interesting that so many good people with good ears are willing to risk their credibility with their subjective claim that they can hear the differences between cables. These claims cannot be ignored.

I beg to differ completely on this one. I do not find it interesting at all and I am convinced that it is best to ignore these claims. Let me explain why.

Let us first assume that interconnect cables cause audible effects in mainstream scenarios, i.e., not due to exotically mismatched components, extremely long runs >> 30 feet etc.. Then the following hypothesis needs to be true:

Yet ill understood (or even unmeasurable) characteristics of electrical cables carrying low frequency alternating current ( << 100 KHz) are causing changes of the reproduced audio signal large enough to be discerned by human hearing.

Why does it have to be true under this assumption? Because our (extremely well-tested) scientific understanding of the matter tells us that we cannot expect any audible differences. Thus, to explain a contradictory observation, we need to assume that our understanding is incomplete (or even downright wrong).

This hypothesis sounds very unlikely to me, especially given that we can design electrical circuits that reliably operate with frequencies up to multiple GHz, i.e., at least 100.000 times higher than audio frequencies.

Now, assume the contrary position, i.e., that in mainstream situations there are no audible differences due to interconnects. Then the following hypothesis has to be true:

Human perception of audio is flawed. For example, it is prone to a number of biases.

This hypothesis has to be true given the assumption, as many people report hearing differences between cables.

Now, in contrast to the previous hypothesis, this second hypothesis is not in contradiction to our scientific understanding. Quite to the contrary, there is a huge pile of research on how human perception in general is unreliable and in particular how what we think or see affects what we hear. Pars pro toto let me mention the McGurk effect, where visual information clearly influences our audio perception.

Now using Occam's razor (or just common sense), which of these hypotheses is more likely to be true? Which assumption is the correct one?

Add to that the fact that people regularly fail to discern between different cables in blind testing situations or even report differences when the cables were not changed at all.

Just my 2 cents
Peter

P.S.: Believe what you must and spend your money any way you like. But be careful making claims solely based on a large amount of people believing something.

[1audio]

The null test can be very useful but the level so far is one or two steps away from being unimpeachable. We really need to test at the output of the next stage in the chain so we capture the effects of noise coupling, interface interactions etc. And there well may be acoustic effects from the acoustic interactions with the cable. There are physical properties of signals over cable that the acoustics will interact with. An old friend manufactured alarm systems based on coax cables strung through fences to sense the fence being disturbed. It worked well.

The Null test also needs to be tested for sensitivity. Bill Waslo has a demo of that. He has a string quartet (I think) that he mixed a Sousa marching band into at -50 dB for one pass. Its completely inaudible under normal conditions. Really obvious in the null test. Something like this process would help arrive where the real threshold of hearing stuff lies.

For what its worth I have tested cables with incredibly sensitive instruments and not found any smoking guns. The things I have found are really tiny and hard to connect to audible effects. I design cables and would really love to have something that can be quantified that I can connect to audio performance. Meanwhile I strive to remove anything that I can identify as having an impact electrically, even if its very theoretical (like magnetic parts of connectors). I do get suspicious when claims are made that defy physics. Even so I have contributed support to long shots like room temperature superconductors (it did not pan out, yet) and carbon nanotube cables (they may really work).

However I do hear differences. A key part for me of this is that on a new design with no prior history there will be no external bias. There is no one to provide expected results. There may be internal bias but it could go either way. I would like to say its all BS, my life would get easier. But I still seem to hear something.

I also find interesting to read reviews of audio products (electronics for example) from reviewers in different parts of the world with no connections between them arriving at very similar descriptions of the "sonic" character of a product. Either the review samples had directs on what to hear, the color and shape of the product has a huge influence on the sound expectations or they are somehow hearing similar things.

Double blind testing and most other current testing regimes do suffer from the effects of over exposure. Hearing the same track several times really makes it difficult to hear differences. Dr. Otala demonstrated to me many years ago the basics of an academic test, with the requirement that the first listening be discarded. That session is going from nothing to something. The second session is where useful data will start to come in. What we perceive has a lot of learning and memory connected making it more removed from what we hear.

I am challenged daily to listen to changes and I know that if they are not gross changes by the end of the day I won't hear them. The short list of test tracks gets very old fast and new stuff takes a while to be useful for aural evaluation.

[Paul.Raulerson]

Hey Peter -

I guess what I don't understand is why you and Prufrock and others are so intent on trying to prove nobody can hear a difference?

I surely don't see people who can hear a difference worrying about forcing people who cannot to admit they can hear it. In fact, just the opposite, everyone I know freely grants that those folks are correct in saying they cannot hear a difference. Without attaching a stigma to it either.

Prufrock brought up the Annoying Rand's famous one million dollar challenge. I would note that anyone who admires that guy should read Michael Fremer's experience with him.

The annoying Randi tried his best to rig the speaker cable test, and when it looked like he was about to loose the money, backed out and quite litterly lied about it. To be fair, one of the cable companies backed out too, but that doesn't change or excuse the way Randi behaved.

Comon guys - that Randi person makes his living fooling people - and he is good at it - look how many people he has fooled into trusting him! Man should have worked for Enron...

In any case, I don't see anyone seriously disagreeing with Denis' results, do you? I see people disagreeing with the wild conclusion that anyone who can hear a difference is hallucinating though. To compare this subject to flying saucers and fairy tales is not reasonable, and merely loose and turbid thinking - in my opinion.

[esldude]

The null test can be very useful but the level so far is one or two steps away from being unimpeachable. We really need to test at the output of the next stage in the chain so we capture the effects of noise coupling, interface interactions etc. And there well may be acoustic effects from the acoustic interactions with the cable. There are physical properties of signals over cable that the acoustics will interact with. An old friend manufactured alarm systems based on coax cables strung through fences to sense the fence being disturbed. It worked well.

The Null test also needs to be tested for sensitivity. Bill Waslo has a demo of that. He has a string quartet (I think) that he mixed a Sousa marching band into at -50 dB for one pass. Its completely inaudible under normal conditions. Really obvious in the null test. Something like this process would help arrive where the real threshold of hearing stuff lies.

For what its worth I have tested cables with incredibly sensitive instruments and not found any smoking guns. The things I have found are really tiny and hard to connect to audible effects. I design cables and would really love to have something that can be quantified that I can connect to audio performance. Meanwhile I strive to remove anything that I can identify as having an impact electrically, even if its very theoretical (like magnetic parts of connectors). I do get suspicious when claims are made that defy physics. Even so I have contributed support to long shots like room temperature superconductors (it did not pan out, yet) and carbon nanotube cables (they may really work).

However I do hear differences. A key part for me of this is that on a new design with no prior history there will be no external bias. There is no one to provide expected results. There may be internal bias but it could go either way. I would like to say its all BS, my life would get easier. But I still seem to hear something.

I also find interesting to read reviews of audio products (electronics for example) from reviewers in different parts of the world with no connections between them arriving at very similar descriptions of the "sonic" character of a product. Either the review samples had directs on what to hear, the color and shape of the product has a huge influence on the sound expectations or they are somehow hearing similar things.

Double blind testing and most other current testing regimes do suffer from the effects of over exposure. Hearing the same track several times really makes it difficult to hear differences. Dr. Otala demonstrated to me many years ago the basics of an academic test, with the requirement that the first listening be discarded. That session is going from nothing to something. The second session is where useful data will start to come in. What we perceive has a lot of learning and memory connected making it more removed from what we hear.

I am challenged daily to listen to changes and I know that if they are not gross changes by the end of the day I won't hear them. The short list of test tracks gets very old fast and new stuff takes a while to be useful for aural evaluation.

Glad you have responded again Mr. Martin. One need only listen to your products to know you have tremendous credibility. It is among the very finest and most transparent I have ever heard. Not flattery either, just gut level experience with your designs.

Make suggestions for what you would do next. I am currently using Wyred4sound amps driving Soundlab Aura speakers. Would you move the difference test to the speaker terminals? What pitfalls of null or difference testing can you fill in for us?

I must admit, my predilection is to go with the rational, scientific conclusions. Yet my experience is hard to refute. I could explain my initial experience with speaker cables which was effectively blind. I am somewhat twisting in the wind here. Very interesting though not very comfortable.


Dennis

[esldude]

BTW, has anyone identified the song I posted earlier as a difference file? It was quite popular. Not say Beatles popular, but not at all unknown. Surely some of you golden ears can easily discern the difference versus the noise it is buried in. Otherwise, I can only surmise none of you can discern the difference between the cheapest, crappiest, included for free interconnect with a DVD player from a sure enough high quality, pure silver interconnect manufactured by Audioquest. Seeing as how you cannot identify the difference, I think it safe saying the difference is meaningless. Or, any interconnect including the cheapest is beyond the ability of the most golden ears to discern.

Have at it folks!

[sandyk]

"Seeing as how you cannot identify the difference, I think it safe saying the difference is meaningless."

Dennis

Or perhaps seeing you only got a total of 34 votes, split 50/50, most people from the opposite side, simply couldn't be bothered ? (grin)

Kind Regards
Alex

[esldude]

I cannot change the laws of physics captain.