Blind Power Cord Test & results

Drubin,

Perhaps I was a bit too jocular in that post. If this obscured my point, sorry about that.

My point was that good experimental designs are very hard to accomplish, and this experiment had so many difficulties, I can’t see how it could be valid as a tool to help decide about power cords. Perhaps, most could see this, but I read this article after seeing it cited several times by others as a source of information to try and decide if after-market PC’s were worth it. Good experimental design is no minor issue. Academic and scientific careers can be made and destroyed in this area. Carefully applied and properly used statistics can’t improve an experimental design with major flaws.

I have yet to read any sort of blind test in audio that had an experimental design that appeared convincing to me, but I read that stuff only when I'm looking for something specific. A frequently cited difficulty, on Audiogon and elsewhere, is that blind testing itself may introduce some inherent bias, but the technorati surely disagree. Many other factors that are more complicated could also be mentioned, but I won’t.

Lots of folks would like to know the answer to questions about upgrading/changing things like PC’s definitively, and that is why such tests have been devised. It just seems like we have a long way to before we get there, if ever.

What a damn shame they didn't consult you before the test. How could they be so stupid? Thanks for setting us all straight.

Welcone to Statistics 101, and so snickering, please.
A not all that close reading of the article will lead anyone familiar with experimental design to conclude that the results are without meaning. I'm sorry I didn't see this thread sooner so my comments could be more current. The sections in quotes were cut and pasted from the article.

1. Reading the article from “Secrets of Home Theater and High Fidelity,” it is apparent that the procedure has many, many steps that might influence the results and that the two groups had different procedures used. The non-comparability of the groups and multiple steps mean that the overall procedure may be flawed. Is there “proof?” No, but there is equally any lack of evidence that this is a valid procedure. Stop, start; un plug, replug;(on multiple components, no less), power down, power up; warm-up; musical selection length determined, how? Half of the participants attended a “training session” the month before. The second trial had musical selections that were longer than the first. Group one (no snickering here, please) had the felt down for the training and felt up for the listening. Group two were felt up both ways. ( I said, “NO SNICKERING!”) Group one ate after the test and greeted Group two. Group two ate before the test with Group one. Lots of experimental manipulation, all of which was quite apparent to the participants. What might this have done? Still, the two groups were different from one another and were different interanlly by virtue of the pre-trainning. At a minimum, the data from the two should not have been aggregated.

“Participants were 80% correct in their responses to the selection from the Berlioz Requiem. Manny calls this “very close to the threshold between chance and perception. None of the other selections produced responses higher than 60%. This phenomenon correlates with John Atkinson’s experience that his participants fared best on massed choral music. If any of us were mad enough to conduct another blind test of this nature, I would choose audiophile recordings of massed choral music for at least 50% of the musical selections. It would be interesting to discover if it would make a difference.”

2. The procedure apparently produced at least one condition that had uniformly positive results, but Manny says it doesn’t matter. How did Manny reach this conclusion?

“In post-test discussion, several of us noted that we had great difficulty remembering what A had sounded like by the time we got through with X. Several participants said that the way they dealt with this phenomenon was by ignoring A entirely and simply comparing B to X without giving thought to A.”

3. Procedures may well have skewed the results.

“In many cases, statistically significant differences could be discerned by participants. In others, no differences could be discerned.”

4. He does not make it clear how he determined this. Even earlier in the review, he noted:

“...that the very procedure of a blind listening test can conceal small but real subjective differences....”

5. Hmmm.....

"But, no, you have to take all the data together. You can't just pick out the numbers that suit your hypothesis. This would be statistically invalid. Same thing with just looking at one music selection."

6. But, if the procedures have many elements that compromise the overall validity, this conclusion is unsubstantiated.

The fact there was some evidence of statistically significant differences some of the time suggests that something may have been going on. Lumping all of the data together is not necessarily a good statistical procedure, particularly with so may manipulations going on and the differences between the two groups and individual participants by having attended some pre-training. With any group, it could be that there is one individual who can detect differences, or one type of music that makes this more detectable. No one is really sure of what to make of statistical outliers (those many standard deviations from the mean), but citing group statistics does not address the issue, particularly with small groups.

"But, we can't do that and claim good science."

7. Calling it science does not make it science.
These procedures may or may not be flawed. What is clear though, is that there is very little statistical power in such procedures -- two small groups with a large number of experimental conditions.

My conclusion is that nothing can be learned from this test as structured. Using statistical procedures to analyze poorly run experiments cannot redeem the experiments. Lots of experiments designed by far more accomplished folks are found to be flawed. This would never be published by anything other than an on-line audiophile publication.

Buy a better power cord and decide for yourself. Get it from a source that allows a trial period.

Rouvin

I don't need someone elses review, I have done my own. I replaced the AC cords on my DVD player and front projector at the same time with VHAudio cryo'd AC cords and the video was dramatically improved, nothing subtle about it. I was not using any power conditioners at the time. This was on a well calibrated system I was naurally familiar with and it was immediately apparent. Perhaps video is easier to perceive than audio.

I've tried various pc in the past and most do change the sound one way or another. A/B doesn't work for me, it usually requires atleast 3-4 days for the differences to by fully noticeable. I have just in the past month went through three different pcs on my source. The first 3-4 days they all sounded very similar, with the only slight noticeable difference in the bass area. After 4 days or so, the differences became more apparent and each takes my system to a slightly different direction.
I don't know the technical workings of this (feel free to jump in Sean,) but I think it has something to do with the pc itself being electrically charged up. From my experience and imho, the neuances of each cord would only reveal themselves after this length. Any A/B comparisons that I have done prior to said time often yield inconclusive results. If I had only done A/B comparisons, I may have drawn the conclusion that they make no differences.

The first time I sat down to compare an "audiophile" power cord to a generic one, I was 100% sure I would find no difference. The idea seemed absurd to me. But listening to certain cords, such as those from Shunyata, quickly demolished that notion. Furthermore, I heard the same things that I subsequently read about in reviews.

This is to me more relevant type of blind testing than sitting through short selections. I was blind to the possibility of differences, and I was blind to the types of differences that others were hearing on these same cables.

I don't kwow whether the cord that was used for testing in this article has a substantial sonic signature or not. I am certain that I could prepare a test between two cords where listeners would hear little or no difference, because there isn't any apparent sonic difference between the cords. (I'm referring to sonic differences, not price differences ; - )

Art

Hmmmm....you think that would work for nookie too or should I stick to my lucky shirt?

This all reminds me of the time I attended a Stereophile-sponsered exhibition/convention (which I believe they hold with some regularity). I was a salesperson at a high-end audio store at the time. At the show, they had one of those "can you tell the difference" events (repeated at least twice, as I recall).
In this case, the comparison was between a top of the line Adcom solid-state amplifier and another amp of a much higher price and, presumptively, of better quality. The test consisted of the playing of ten sets of two different auditions of the amps. Each set of ten consisted of our listening "blind" to two auditions and, then, writing down whether we thought that the particular audition was one of the two different amplifiers, or whether it had, in fact, been of the same amplifier played twice. We were told to write down "same", or "different" for each one of the ten sets of auditions. We were told to not try to identify which specific amplifier had played at each separate audition. Presumably, that would have confused us, utterly, or even, perchance, driven some of us mad.
It was a large room, of about two hundred people. I had the good fortune to be seated in the rear corner of the room. I had decided, counter to our instructions, that it would be more challenging, even, perhaps, subversive, to, indeed, write down the name of the specific amplifier that I believed played each time.
I made all my decisions within the first two seconds of each audition. The person seated next to me actually stood up and complained that my responding so quickly was distracting and confusing him. This pleased me because, as I am a philosopher, I'm in the business of distracting and confusing people.
To make a long story even longer, I was right nineteen of twenty times. (Naturally, I blamed my one mistake on the fellow seated next to me.)
How was I able to do this? Simple. I didn't try to hear any differences, at all. Instead, I relaxed into a near meditative state and concentrated on "listening" to how my body felt. I, then, immediately responded according to how my "mood" had changed the instant the music began to play--and, luckily, one amp made me feel better than the other. I kept my conscious mind nearly empty (something that I can do quite easily). Most importantly, I never left myself enough time to second-guess myself.
There is an instructive and brief Buddhist tale about a monkey who is so desperately thirsty that he sat by a stream and grabbed and grabbed at the flowing water such that he could never get a drink. But, as soon as he released his grip, the water flowed immediately and effortlessly into his cupped hands. Thus, his thirst was sated.
Don't grab at the river of music as it rushes by. Dip your hands in, let it pass, and you, too, can effortlessly drink from it, as you're caressed by its ebbs and flows.

"Pabelson I love discussions/arguments about technical discussions."

I think I may be retarded.

Eldartford....I'm glad you caught the sarcasm anyway. It's sometimes hard to convey without smiley faces. The one that rolls his eyes works pretty well. :^

QUOTEIf I believe, based on listening and science, that some audio tweek doesn't, and cannot possibly, work, a hundred people saying it does won't have much luck convincing me.QUOTE

LISTENING + SCIENCE is probably a good thing. It's the ones that rely strictly on science (or a/b comparisons) that bother me. BTW, a/b comparisons is NOT "listening".

Pabelson I love discussions/arguments about technical discussions. I also believe some number of technical explanations marketed by companies are BS and deserve scrutiny. What I was thinking of were technical discussions where a subjective counterpoint is introduced stating that everyone is being cheap and also the the lame "its all in your head" one-liners when posters are discussing their listening experiences with tweaks, cables, etc.

Dragon1952...You also, and others still miss the point about the ROLE of a scientific explanation of physical effects. I will say it another way.

Not everything requires an exact explanation. (Don't misquote me!). I believe in Gravity, even though its explanation is imperfect.

If I believe, based on listening and science, that some audio tweek doesn't, and cannot possibly, work, a hundred people saying it does won't have much luck convincing me. But if one guy can show me HOW it functions then I cannot deny that it works.

Psychics don't have to guess numbers to be psychics. That would just be a game--and there are more important things to be done helping people.

You guys need to see a good clarvoyant psychic to find out what can he/she tell you...whether reading the cards, shells, tobacco smoke--you name it.

Whith psychic power and primal intensity,

***

There is a logical train of reasoning going on here. We hear a repeatable thing, and look for reasons why it is a repeatable thing. But, just because we have not found many reasons why yet, is no cause to dismiss it.

My link to the Bumblebee story
http://www.pass.maths.org.uk/issue17/news/bumble/index-gifd.html

This is not "religion" or anything like it. It is simply another case where the scientists have not produced much proof to explain a valid repeatable observation. But they have produced some, and even that small bit of proof(differences in resistance, impedance, capacitance, dielectric) shows that there can be some differences that will be audible.

Is this must be the new "scientific" game? "If an easy answer isn't apparent, it must be psychological."?

Just like the bumblebee story shows, scientists don't know everything, never knew everything, and are not likely to ever know everything. Evidently, there are some who think they do.

As I posted earlier, member Aball has written on another thread about a French and German scientific consortium who is studying this very subject, and have already found some things that can be measured, and can further explain why we hear differences. These are hardware measurements, not psycho-acoustic measurements. They have found some kind of "micro-corona" effects around wire which is measurable, and they have produced some kind of measuring device to quantify it. I don't know much about it, but at least someone is doing something about it.

I don't much care about it myself, since I can easily hear the things needed for me to make an informed decision. However, for some who can't trust their ears, and have to lean on numbers for their audio purchasing, this may be helpful.

Also, in future threads, subjective discussions should not be interrupted by contrarian physical explanations and vice-versa.

This is a misconception. These threads get onto the question of "what's real/what's in our heads" because people begin offering totally nonsensical explanations for how cables/tweaks/PCs/etc. work, and others pointed out their errors. Now, maybe you think Audiogon is served by a rule that says, only *incorrect* technical explanations may be posted. But when I say something wrong (and I do), I want to be set right, because that's how we all learn.

In a very interesting post above, Donbellphd notes:

Is this thread about auditory perception or religion? I get the impression it's about religion... (...)

Somewhere in-between, I'd say, and closer to religion: music is an emotional experience and the equip attached to its reproduction seems to borrow from that emotionality... hence a partial (at least) explanation of

...the inability to follow a logical line of reasoning

. As such it could be termed

an anomaly (REPRESENTATIVE) of our population

. There must be similar anomalies representative of other populations -- music maybe (as in, which is the best performance of Mahler2 and why).
Other than that, I also agree that some of the things tossed around make little sense including, sometimes, blurb tossed around by manufacturers of reproduction equip.
At the end of the day, most of us don't know much about circuit design and loudspeaker modelling -- nor should we. Add to that the bickering between engineers who DO know about these subjects which seems to add to the population's confusion...
Cheers

I never believed in sonic differences of power cords, and I laughed at those who did. Then, when I finally broke down and decided to try a high-end cord, I couldn't believe the improvement. Even a skeptic friend of mine was immediately converted after he heard my new power cord.

I have since used many power cords better than this first upgraded cord. I have no interest in reading 'tests' that discredit power cord differences, as I know, beyond a shadow of a doubt, that they can make as much of a sonic difference as different interconnects make. Yes, I'd like to know why and how they do this, but until and if the scientific reasons manifest themselves, I'm satisfied to know that they do.

I can listen to one power cord on a component using 2 or 3 music selections, and then switch to another cord and tell you what the sonic differences are. I can also have one cord in my system for a week, then change to another cord and be able to hear that cord's signature clearly. I have put stock cords back in only to be horrified by how inferior they sound.

I don't like spending money on power cords, and wish they all sounded the same. Problem is: they don't.

Despite my reaction to his posts, I agree with Twl more than I disagree. The parameters such as system and room need to be addressed and while ABX is good tool, it is not worth much on many levels in audio, especially in private circumstances. Also, in future threads, subjective discussions should not be interrupted by contrarian physical explanations and vice-versa. There is no point to it.

I find many of the posts in this thread disturbing. I hope the inability to follow a logical line of reasoning is an anomaly unrepresentative of our population generally. One poster even tosses around statistical significance as though it had meaning outside of sampling, distribution, variance, and inference. But that's just misuse of jargon. I'm really concerned about the apparent inability to reason logically from premises to conclusion. Is this thread about auditory perception or religion? I get the impression it's about religion: You are either a believer (that there are audible differences that can be heard by the discerning few) or not.

Although I was director of a high-tech research center, my original training was in psycoacoustics, particularly binaural auditory processing. I've been addicted to HiFi since before stereo. I admit my speakers are bi-wired, and I have no idea if it makes a bit of audible difference, but I like them that way.

db

It is annoying to me how little audiophiles/public understand science - not in specific examples like bees and PCs per se, but in the way scientists are supposedly rigid, archaic formulists reminiscent of Pink Floyd’s The Wall. In my experience, scientists go to the fringe of knowledge and theory with a lot of grace, unlike the people who try playing the role.

I personally believe cables do make a difference and knowledge of the make-and-model has an influence of perception through expectation. I hope most phile’s, in the silent majority, are in the same boat. And like I stated ABX and blind between-subject testing are perfectly viable in eliminating expectation. An experiment’s procedure may be flawed and the conclusions may not fit the data, but I have yet to read or hear any logical reason why these tests are inherently flawed. One may not like the results, but ya' need more than that to discount the test.

Bumblebee physics myth:

http://www.howstuffworks.com/news-item223.htm

You know, scientists say that bumblebees can't fly, and that from a technical perspective it is impossible. Yet, bumblebees fly all the time. Perhaps we need to do some A/B/X testing to see if we actually are seeing bumblebees fly, or if they are actually not flying, and we are imagining it.

For a hundred years, thousands of scientists and mathematicians have tried to explain how bumblebees fly, and still can't explain it, even to this very day, and this very moment.

I suppose that some here think that we are imagining these black and yellow furry insects flitting about our yards, blissfully ignorant of the "proven fact" that they cannot actually be there.

I'm sure that there must be some psychological explanation for all of us seeing these phantom apparitions that could not possibly be doing what we think they are doing.

You know, it's amazing how widespread these sightings of bumblebees in flight are. One would never think that it could possibly be so pervasive in a society of thinking people who should know better.

Bumblebees have been measured, tested, observed, computer modeled, mathematically analyzed, real-life modeled, and it has been determined that they cannot fly. Boy, I feel alot better, now that I know that.

QUOTEDon't argue that it exists...tell me how it works.QUOTE

Exactly...it doesn't count unless you can explain it! Kind of like why we're all here. We aren't, really, unless you can explain it. Again, that's why scientists get the big bucks. Until they explain it, I won't believe I'm really here...plain and simple. :^

Lmack...You missed the point about the psychic. No doubt you would believe her, although the trick is probably done by a mirror or something like that. The point is that if the mechanism for psychic power were discovered, then it's existance would be accepted by sceptics. Don't argue that it exists...tell me how it works. You may not care how it works, but that's your ticket to credibility.

This is an exercise in understanding human nature, not audio.

Bye.

If you can't hear a difference, what difference would any "scientific" test make to your listening experience? For those of us who can hear a difference--where we have put ourselves to the "test" of reliably distinguishing between some cords in our systems--what is there to prove? I don't really understand what explains the differences I have heard between some cords, interconnects and speaker cables. Nor do I care. Nor do I want to convince anyone else, beyond recommending that they listen for themselves. No one is threatening to deny cord nonbelievers their rights and liberties. As for the psychic phenomena comparison: if someone could reliably tell me what numbers I had written down, out of her view, I wouldn't doubt she is "psychic." While scientists would no doubt like an explanation of this phenomenon, the absence of a scientific explanation would bear not at all on the reality of the phenomenon. So I am not sure why the science-types continue to insist on proof from those of us who are mere listeners--unless they are actually directing their skepticism only to those science-types who also claim to be able hear differences between some cords.

Some people believe in psychic phenomena...

And some people are Psychic phenomena!!!

Joke aside, Eldart, don't confuse metaphysical with psychic...

QUOTESo, people who want to convince me that exotic power cords affect audio equipment, need to come up with some rational explanation as to how this might happenQUOTE

Right on! I mean, heaven forbid we should have to listen ourselves and make our own decisions. That's why scientists get the big bucks, right? :^

Twl...No doubt that "something is going on", but the question is: should the investigator be a scientist or a psychologist. Probably both, IMHO.

Some people believe in psychic phenomena, and many tests have been devised to try and prove, by statistical means that psychic phenomena exist. No one is convinced, except those who believed before the tests. However, IF someone were to discover, not that it exists, but HOW it works, some kind of electromagnetic radiation between brains, then it's existence would not be in question, even by people who lack the ability.

So, people who want to convince me that exotic power cords affect audio equipment, need to come up with some rational explanation as to how this might happen. So far the various "scientific" explanations that I have heard fall short of credibility.

Something is going on here with these cables, and it would behoove us to find out what it is, and why it is.

This is an excellent example of assuming one's conclusion. If every scientist did this, we wouldn't know anything at all.

Scientists *do* know why people hear differences between cables. Some others, it seems, would rather not know.

I'd suggest this approach.

Amongst the audiophile community, there is a very significant statistical majority that there are audible differences in cables. These are people who have done all kinds of listening tests in their home environments, and many would have preferred to not spend any unnecessary money.

These differences are statistically significant enough to comprise a valid observed phenomenon, over a disparate group of individuals.

Now, the scientific response should be that since existing electrical testing methodology has only shown minor differences,and that A/B/X testing has not determined anything sufficient, that there must be some other testing methodology found to either support or refute this widespread observation.

Case in point: When optical communications networks are used, fiber-optic cables carry the signals. Electricity is applied to one driver, and comes out the other end's receiver as electricity(of course opto-couplers are used in this case, but bear me out). If I took that fiber-optic cable and tested it for electrical characteristics, it would seem that it wouldn't even carry any electricity, and it won't. But that doesn't mean that signals are not carried on it. You have to design your testing protocol to measure what you are trying to determine. When we add in the opto-couplers and know(ahead of time) that we are transmitting light signals with couplers on both ends, then we can measure the performance adequately. Similarly, we don't really know for sure(and this whole thread bears this out) what we are trying to measure. All we know is that the existing measuring techniques are apparently not adequate to account for a statistically significant and widespread observation.

So, one way to deal with it, is to just "dismiss" it as folly, or imagination. The other way is to figure out why the tests are inadequate, and determine new tests that actually can make some headway to finding out how to measure what is so commonly observed. The first step in this is to try to determine what the cables are doing that is not in our testing.

If every scientist dismissed everything that could not be readily measured at the time, we wouldn't know anything at all. Measurements are made to quantify observed phenomenon. Anything that is a statistically significant occurrence, justifies further investigation to find tests that can quantify it, whether they be electrical tests or acoustic tests, or whatever.

Something is going on here with these cables, and it would behoove us to find out what it is, and why it is.

All my power cords are blind, I don't need to test them to verify that.

In violent agreement, as they say.

Drubin:
I agree that you can hear differnces "right away" in most cases. However, my point was that conclusions based on initial impressions could be quite "misleading".
I guess we are on the same page.

Perhaps misleading if you are trying to choose which you prefer. Less so if all you are trying to do is detect the difference. When I make a cable change at home, I can hear a difference right away. A day later, I sometimes feel differently about the difference I am hearing.

I have experimented with several power cords over the years spanning the price range from $100 to $3000 . I have observed that all of these cables irrespective of pedigree require some "settling time" of up to several hours to sound their best. Consequently, I think that PC cable evaluation can be very misleading under the conditions of "double blind testing". In my system I can easily hear differnces among some cables.

Subtracting the "blind", audiophiles essentially ABX everything they try in their system. While the hometheaterhifi experiment has problems affecting its validity, these problems are not inherent to ABX. Two factors that apparently people seem to be implied with ABX are time and stress. Time does not have to be a parameter, really. It could be a factor with this experiment - I think the training was too short, but it does not have to be. Although stress is typically not the significant contributor people think it is to cognitive tests, it too can be varied (and tested if one wants). What I would want with an ABX test for PCs is to mimic home trials, without revealing the pc models. That has practical difficulties, but...

Another problem with this experiment is that there is no real hypothesis and barely a conclusion. This subject is difficult to discuss when people are coming up with wrong, overly broad and multiple conclusions. There is only one conclusion per variable which includes the conditions of experiment, and there should have been a distinct hypothesis to eliminate the BS. The hypothesis determines the test procedure...there is no general best way. While the experiment was a good exercise, it was too flawed, imo, to support whether or not "pcs make a difference". Plus no one experiment can yield such a sweeping conclusion. Other factors can be manipulated that could affect the results (that is why I stated the conclusions must include test conditions).

PS -

"Some people can hear the differences and repeatedly get them right, while some people can't."

"There is so much psychological stuff at play here that we can't tell if the differences are real or imagined"

These are not factors after decent sampling, and statistical analysis.

Jayarr said:

the way to test A vs. B is to try to detect differences

I agree insofar as this would be a FIRST objective. Ultimately, a testing would (should) lead to choice since, at the end of the day, a) it's a market & b) we invest in (meaningful?) "improvements" -- or not at all!
HOWEVER, cords seem extremely difficult to test with the "quick succession testing method". You have to power down, change (some PS's will lose juice in the process), power back up and listen immediately -- in order to power down again, etc, etc. I'm not sure there is time enough for the "repowered up" system to reach sufficient operating/ resolution status to easily gauge differences -- or none...

Having said that, I had ONE such successful experience. I use TWO amps and happened to change cord on ONE of the two. On power up, the amp played lower (amplitude) than before. Did it again, same thing. Kept the amp powered up for ~15mins with the cord under test -- no cigar.

I agree with Ohlala. I think the way to test A vs. B is to try to detect differences, NOT try to identify the sound of A or the sound of B. IOW, blindly and randomly compare 2 power cords together (AA orAB or BB) to see if you can discern a difference. Your response will be : Yes, there is a difference between the two or No, there is no difference. Repeat this random pairing 10 times and see if you could detect differences when the pair tested was indeed different(AB) and see if you were correct identifying when a pair was indeed the same(AA, BB). If the results were close to 50%, then you could not detect a difference between the 2 PC's. This way you are not required to know the unique sound of A(or B) intimately enough to identify it right away. I'm not sure this makes the testing anymore valid but I would think it should make it easier to do better than chance. Subsequently, if a difference can be discerned between 2 PC's then you can try to decide if the difference was significant enough to justify any price differential. Also you can decide which PC's sound you prefer and why. This can be ascertained with long term listening tests.

Good post, TWL. I would lean toward #2 and/or #6. Since I always hear differences myself in my system, #1 and #7 are not conclusions I would ever reach for myself. Everyone wants to believe #4 because they think that they have the real golden ears. There were plenty of golden ears at this test who did not do well. Tom, maybe even you would have had a tough time of it. :-)

And Warren, here's a big sloppy kiss for you: Mwaaaaahh!

Eldarford, call me when that happens..I want to be there...I'll bring the marshmellows...lol

After reading the test article again, it seems there could be several different conclusions.

1) There is not enough difference in power cords to be detected, therefore don't waste your money.

2)Blind A/B/X testing is not an adequate test to determine the differences, so different testing methodology is needed.

3)There is so much psychological stuff at play here that we can't tell if the differences are real or imagined, and the testing protocol provides so much stress that even if there are differences, the people can't determine them under those conditions.

4) Some people can hear the differences and repeatedly get them right, while some people can't. It may have nothing to do with the cables, but has to do with the people.

5) The test system and room, while being termed "state of the art", mucked up the sound so much that the cord differences were obscured in the mess.

6) The use of the Exactpower line scrubber did most of the work that the cables were supposed to do, thereby negating most of the differences that would have been heard when using unfiltered AC power.

7) We now can all go out and get cheap systems now, and get another hobby. We have seen A/B/X studies of cords and amplifiers finding no statistical proof of differences, and probably the same will be true of any other audio products they test. Therefore audiophilia as a hobby is extinct. How about flower arranging, or stamps?

I personally subscribe to conclusion #2, even though I have done A/B/X testing myself in the past, many times, and had no trouble with it. I think that too many variables are at play that can cause many of the participants to be unsettled and incapable of making good quality judgments under the conditions presented.

I congratulate all participants, especially Drubin, who gave it a valiant effort.

Drubin: My post was not to say that one CAN NOT tell differences right away, but that many differences are subtle and could easily be lost "in the heat of the moment".

As i mentioned above, if i had not heard instant differences when changing one power cord for another power cord, i would not have taken the time to confirm or deny what i heard via test measurements. The differences were that obvious, but then again, i was already familiar with the sound of my system and that song as played on it. Had i not been familiar with either the components or song used, those differences might not have jumped out at me quite as quickly.

Performing AB testing with a completely unknown set of variables is kind of like trying to find your way in an unfamiliar territory with a lot of distractions taking place. This is much harder than if you've been down that road many, many times before and know what to expect. This is not to say that it can't be done, only that it probably won't be nearly as quick and you might not be quite as sure-footed in the decisions that you make. Sean
>

Drubin...You are brave! Hold fast to your beliefs, even as they tie you to the stake, and light off the straw.

Warren, what are you talking about? I think you're not paying attention.

Sean, I think you are incorrect to dismiss the process as completely as you appear to be doing, and I'm surprised to read your post. I'll bet that every one of us has heard differences aplenty on other peoples' systems with music they are not familiar with. The panel spent quite a bit of time up front listening to the system, the musical selections, and the two different sets of cords. We could all hear the differences, no problem, until the screens were put up and the test started. (By the way, most of us thought we identified the choices correctly.) The system's owner, who has a great ear and knows his system intimately, fared no better than many of us as far as I know.

We're not talking about Electraglide vs. Elrod here. This was $3 stock vs. Valhalla. I'm still hoping someone can offer a solid, rational explanation for how and why the testing procedure obscures differences.

Is everyone familiar with the old Stereophile Test CD where Gordon Holt reads his essay "Why Hi-Fi experts disagree"? As he reads through his piece he uses 14 different microphones. The differences in the sonic characteristics are huge. If the sound characteristics are so greatly affected by which microphone was used, I wonder why we get so worked up about differences with power cords, and the like, which, if they really exist, are so small that most people can't hear them.

And about Albertporter's postings...of course I always read them with care. He obviously has the time and money to experiment with equipment that I could not justify buying, and, most important, he (usually) does not resort to name-calling. However, on some issues I feel free to disagree. No problem.

Been down this audio road before. The best you can do with an ab power cord test is decide which you prefer, with that particular system, at that time, with that recording. After deciding which cord is preferred, does that mean it will perform similarly with a different system? I don't think so. Excellent hearing acuity is a quantifiable thing like vision acuity. We may both view the same Monet, but see different things, have different impressions, though we pocess the the same visual acuity. The same goes for hearing, as well. I have golden ears. You have golden ears. I'll bet our listening experiences will be disparate enough to make us wonder enough....who ears are more golden?

...not even taking into effect what powering off does to solid state and tube gear for the first few minutes...

That *could* be a major compromise in a cord testing situation... unless one listened for a while to each sample under test.

One has to be intimitaly familiar with all of the gear being used and the recording in order to identify if there has been a change made. Picking specific parts of a song to use as a cue tends to work well, but if one wasn't quite familiar with the song or how it was specifically reproduced on the system to begin with, they would be guessing just like anybody else.

As such, short term listening tests when one is not familiar with the system and / or the recording is next to useless, especially when the differences may be quite subtle. Expecting someone to familiarize themselves with both a song and potentially different types of presentations at the same time is too much to ask simultaneously.

As such, these types of tests are basically set up to produce a negative right from the beginning. The one exception is when you get a highly trained listener with excellent hearing acuity. Even then, they are swimming against the current for the above mentioned reasons. Sean
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Good posts Drubin. The "which is this" task can be difficult. With it, I would not conclude PCs to be snake oil and would have preferred if the experimenters used two groups, instead of one group given two variables - as in "is there a difference between A and B?"

What is always obvious is that audiophiles in general, unlike the professionals (Pabelson), are emotionally and knowledge-wise unfit to conduct blind testing. Its goal is to eliminate just one variable, but you’d think it was a religion. Personally I don't see why people should use it at the level of the individual consumer to decide the worthiness of each component - what a pain!, - at a larger level, however, which testing never has or will attain in audio, it has merit.

Eliminating variables is a good thing, and is practiced too little in audio, especially audiogon where anyone proclaims “truths” with any measure of experience or knowledge-base.

Again, this test was not about how you decide what works or what you prefer. It was about whether or not you can hear a difference under controlled conditions.

I think we have all preferred the "lesser" product at one time or another. That does not refute the hypothesis that we are influenced by brand, packaging, etc. etc. Price is but one component of brand perception.

The other night I had assumed an expensive power cord was going to be an improvement, so I hooked it up without listening to it and before everyone arrived for the music session.

About an hour into the music I ask one of my group members if he thought things were "off."

He agreed, and I put in the less expensive cord and the system improved drastically.

I have no problem with that, it saves me money every time that happens. I admit I had a prejudice for the premium cord that had proven itself dozens of times in other situations.

Conclusion? I still use the premium cord everywhere it works and NOT where it did not work. The score is two pieces of (newly acquired) gear that did not respond well to the "high priced" version and nine places where the "high priced" cord was the clear winner.

As I stated early on in this thread. You use what you think will work and then test (long term listening) to see what the facts are.

If this test had been done "blind" I could have easily reversed the brands, based on my past experience.

Does this prove ABX is a superior way to determine what brand to use? No, it only proves humans are influenced by what we learn and if your an adult about it, you admit when testing goes against preconceived notions and go with what WORKS.

In addition, many cords do not respond well to short term listening. Some brands change tonal balance simply by plugging and unplugging them from the equipment, this not even taking into effect what powering off does to solid state and tube gear for the first few minutes.

I hesitate to bring that point up, because someone will now argue that the cord does not change if moved and that there is no effect in powering on and off various pieces of gear.

Again, reason to listen long term, if for no other reason than to remove the possibility of those variables.