In the homecinema-fr.com (http://www.homecinema-fr.com/forum/index.php) forums, I organized a listening test of CINCH audio cables (the ones between CD player and amplifier, asymetric).
We were 5 people trying to show an audible difference between such cables in a blind setup.
Protocol
The protocol was this one :
Phase 1 : we listen to the system, we listen to the CDs, we listen to the cables, and look for the differences that they can bring. This phase ends as soon as we have chosen a system and a musical sample with which two cables show plainly they difference.
Phase 2 : we listen in a simple blind setup in the following way. Among the chosen cables, a drawing of lots is performed twice. The first result is plugged in, and the musical sample is played. The same is done with the second drawing. The listeners must tell if the cables were different or the same. When one listener at least has given 7 right answers in a row, phase 3 begins.
Phase 3 : The listeners who managed to identify the cables in phase 2 go on with the trials begun in phase 2. The total number of trials depends on the number of listeners in such a way that the probability that one listener at least finds all the right answers is less than 1/100000. The success condition is then "one listener at least gets a score superior or equal to R right answers for S trials". The validity of this success is given by the probability that one listener at least gets this score or a superior score.
Listening setup
The system was composed of an SA15 Marantz CD/SACD player (1,500 €), an RCD02 Rotel CD Player (600 €), a 530 Acuphase integrated amplifier (8,000 €), Prism RC500 Taralabls speaker cable, and Magellan Concerto Triangle speakers (15,000 €).
Here are some of the cables that we listened to (click to zoom in) :
(http://perso.numericable.fr/laguill2/pictures/homecinema-fr/20050508-cablesmodul/PICT0219S.jpg) (http://perso.numericable.fr/laguill2/pictures/homecinema-fr/20050508-cablesmodul/PICT0219.jpg)
From left to right :
Taralabs RCS Reference generation 2 (560 € for 1 meter).
DIY ACR (4.5 € per meter)
DIY RG179 silvered copper + golden / Teflon plugs (4.5 € per meter)
DIY by Ogobert
DIY by Ogobert (unshielded)
2.30 € standard cable, with an optional 5 meters extention (between 4.50 and 8 €)
Audioquest Diamondback (137 € for 1 meter).
There was also a Van Den Hul Ultimate the first.
The tests didn't pass phase 2. No one managed to identify reliably if the cables were changed or not between two listening sessions.
Here is a full account in French with pictures, and many instructive details about the listeners answers : http://www.homecinema-fr.com/forum/viewtopic.php?t=29781210 (http://www.homecinema-fr.com/forum/viewtopic.php?t=29781210)
The protocol and the probabilities were discussed in this thread : http://www.homecinema-fr.com/forum/viewtopic.php?t=29770792 (http://www.homecinema-fr.com/forum/viewtopic.php?t=29770792)
The tests didn't pass phase 2. No one managed to identify reliably if the cables were changed or not between two listening sessions.
Copain - I am so happy to see the results of your tests. They seem to support what common wisdom, physics and engineering indicate: wire is wire is wire. Those high-end salemen are selling snake oil. Chapeau!
I'd be more than interested to see a CINCH vs. SPDIF comparison, with same prepositions. Needless to say, i expect CINCH to perform better .,...
Clearly your skepticism interfered with the harmonious transfer of the higher order musical energy signatures within the audiophile cables. Also it's rather obvious your listeners didn't have golden ears and were unable to appreciate the significant improvements to the synergy that is present when using high-end audio cables.
And the scary thing is, there are some hard-core "audiophiles" out there who would probably think that and be serious about it...
Nice test, i love it.
You could argue the listeners were not trained well enough or had bad ears, but it certainly proves that any difference, if present, is not at all clear for everyone to hear. A nice additional test might be to setup a high end mic & recording system and analyse the data, it'd be interesting to see if there are inaudible differences between cables. And if so how cheap a cable can be and still perform exactly like the expensive ones.
With a €25k audio setup it doesn't hurt to spend more than €2,30 on audio cables though as you'll want some physical durability and the cost will still be a tiny fraction of the total setup.
The tests didn't pass phase 2. No one managed to identify reliably if the cables were changed or not between two listening sessions.
For me is very pleasant to confirm (with your test) that many years of electronic engineering were not wrong.
Many electronic engineers (including me) knew this, but a proper listening tests confirms it.
Thanks for so interesting report.
I'd be more than interested to see a CINCH vs. SPDIF comparison, with same prepositions. Needless to say, i expect CINCH to perform better .,...
[a href="index.php?act=findpost&pid=297082"][{POST_SNAPBACK}][/a]
SPDIF uses CINCH plugs !
Clearly your skepticism interfered with the harmonious transfer of the higher order musical energy signatures within the audiophile cables.[a href="index.php?act=findpost&pid=297093"][{POST_SNAPBACK}][/a]
But we
heard the differences ! Better bass handling, better decay, better stereo image, clearer harmonics, less bass...
The only problem is that we also heard the differences when the cables were the same
A nice additional test might be to setup a high end mic & recording system and analyse the data, it'd be interesting to see if there are inaudible differences between cables. [a href="index.php?act=findpost&pid=297099"][{POST_SNAPBACK}][/a]
I've added the RMAA results of most cables.
Anything which is magnetically shielded should be enough IMHO.
I'd be more than interested to see a CINCH vs. SPDIF comparison, with same prepositions. Needless to say, i expect CINCH to perform better .,...
[a href="index.php?act=findpost&pid=297082"][{POST_SNAPBACK}][/a]
SPDIF uses CINCH plugs !
[a href="index.php?act=findpost&pid=297191"][{POST_SNAPBACK}][/a]
I guess he was talking TOSLINK vs. Cinch ... or bit-true against bit-true ...
Why not glass vs. plastic optical s/pdif? Some people really believe they can hear the difference.
Nice test. What a pity I can't read the links!
A team of German magazine ct once performed a test high end chinch vs. simple wire (both as digital electrical cables) and couldn't tell the difference...
Would be interesting to do the same for analog. How cheap can the cable be then ?
How cheap can the cable be then ?
[a href="index.php?act=findpost&pid=297208"][{POST_SNAPBACK}][/a]
Obviously, it can be cheap enough to still offer proper electrical and mechanical (plugs are most important IMO) abilities.
The only problem is that non-shielded cable can be interfered by surrounding cables and magnetic fields.
Interesting test indeed. Some crude Babelfish translation of the french thread: "Results of the test as a blind man" (http://babelfish.altavista.com/babelfish/trurl_pagecontent?url=http%3A%2F%2Fwww.homecinema-fr.com%2Fforum%2Fviewtopic.php%3Ft%3D29781210&lp=fr_en).
I'd be more than interested to see a CINCH vs. SPDIF comparison, with same prepositions. Needless to say, i expect CINCH to perform better .,...
[a href="index.php?act=findpost&pid=297082"][{POST_SNAPBACK}][/a]
SPDIF uses CINCH plugs !
[a href="index.php?act=findpost&pid=297191"][{POST_SNAPBACK}][/a]
I guess he was talking TOSLINK vs. Cinch ... or bit-true against bit-true ...
[a href="index.php?act=findpost&pid=297202"][{POST_SNAPBACK}][/a]
......
/me goes to hide in the cellar ......
Interesting test indeed. Some crude Babelfish translation of the french thread: "Results of the test as a blind man" (http://babelfish.altavista.com/babelfish/trurl_pagecontent?url=http%3A%2F%2Fwww.homecinema-fr.com%2Fforum%2Fviewtopic.php%3Ft%3D29781210&lp=fr_en).
[a href="index.php?act=findpost&pid=297232"][{POST_SNAPBACK}][/a]
The link doesn't work for me:
phpBB: Critical Error
Could not connect to the database
The link doesn't work for me:
phpBB: Critical Error
Could not connect to the database
[a href="index.php?act=findpost&pid=297247"][{POST_SNAPBACK}][/a]
This is because the homecinema-fr.com website is down for the time being.
Anything which is magnetically shielded should be enough IMHO.
[a href="index.php?act=findpost&pid=297201"][{POST_SNAPBACK}][/a]
Why do you need a magnetic shield ? Only esoteric cables include magnetic shield in addition to the conventional shield. None of the tested cables was magnetically shielded.
The only problem is that non-shielded cable can be interfered by surrounding cables and magnetic fields.
[a href="index.php?act=findpost&pid=297218"][{POST_SNAPBACK}][/a]
One of the tested cables was not shielded, and didn't perform worse than the others. Though we did not listen to it much.
The original RMAA results showed a stronger 50 Hz component with it, in the background noise, but the new results that I posted after the test didn't show it. The devices had been moved between the tests, and the cables position was not the same. I think that this is why the DAT deck did't pickup the 50 Hz hum the second time.
Anything which is magnetically shielded should be enough IMHO.
[a href="index.php?act=findpost&pid=297201"][{POST_SNAPBACK}][/a]
Why do you need a magnetic shield ? Only esoteric cables include magnetic shield in addition to the conventional shield. None of the tested cables was magnetically shielded.
[a href="index.php?act=findpost&pid=297250"][{POST_SNAPBACK}][/a]
The agressor signals are electric-magnetic waves. Waves with only a magnetic or only an electric field don't exist. Kill the electric part, kill all.
Would be interesting to do the same for analog. How cheap can the cable be then ?
Wait... in this test, the
analog signal was run over the CINCH cables, right? (else it wouldn't even be worth the trouble)
Yes.
I think you were under pressure and that made you confused.
I am sure there is a difference, even if I can't hear it eiter.
Was not the color of the cables different?
That alone should have made enough difference to SEE!
Oh c'mon, this test is clearly corrupt! I bet these homecinema-fr.com people are heavily sponsored by the producers of ... euhm ... cheap cables, yes, that must be it!
LoL, someone made the horrible mistake of trying to post this over at Head-Fi in the cable forum.
Evidence of what I've always suspected...the only appreciable difference between cables is how they look.
Personally, I'll pay extra for pretty blue cables.
Great post, Pio2001. It's always nice to have a good test confirm that interconnect cables don't make a big difference, as many have suspected for a while. I think the take home lesson is that, when buying interconnects, go for a decent quality shielded cable with good plugs - anything more than that and you are wasting your money.
It would be nice to see a similar test with speaker cables. I suspect that the vast differences in measured parameters (R, L and C) between different cables will have audible effects. It would also be interesting to measure speaker cable parameters, use transmission line theory to calculate the effect they will have on the signal, and see whether listeners report these same differences.
It would be nice to see a similar test with speaker cables. I suspect that the vast differences in measured parameters (R, L and C) between different cables will have audible effects. It would also be interesting to measure speaker cable parameters, use transmission line theory to calculate the effect they will have on the signal, and see whether listeners report these same differences.
[a href="index.php?act=findpost&pid=297402"][{POST_SNAPBACK}][/a]
Vast differences in L and C might result in audible effects - but the differences of real-world speaker cables are never going to be vast enough. This has been blind and double blind tested many times in the past.
R can make an audible difference when the speaker cable is too long vs the gauge of wire used. The practical effect of the increased R is to decrease the damping factor of the amplifier, potentially to an audible level. Interestingly, listeners sometimes percieve the high resistance cable as sounding better than the low resistance cable. Indeed, it is often found that the low damping factor is what gives tube amplifiers that 'tube sound'. When resistance is added in series with a solid state amplifier to match that of a particular tube amplifier, in many cases it is found that the tube amplifier does not sound audibly different to the solid state amplifier in a double blind listening test.
Very interesting test. Thanks
It would be nice to see a similar test with speaker cables. I suspect that the vast differences in measured parameters (R, L and C) between different cables will have audible effects. It would also be interesting to measure speaker cable parameters, use transmission line theory to calculate the effect they will have on the signal, and see whether listeners report these same differences.
There definitely are differences between different speaker cables, but most of them are mainly going back to their R component, influencing the electrical damping factor Q es and thus the behaviour of the bass speaker around the resonance frequency. A High R value will increase Q es, leading to more but less controlled bass.
There are also measurable and audible differences for the mid/hi range, but funny enough you can get rid of most of them by simply making the effort of adding several R-L-C circuits to the crossover of the speaker, in order to get rid of peaks in the impedance curve of the speaker. Especially helmholtz layouts ( bass-reflex ) will react very sensitive to impedance compensation circuits of the 2nd impedance peak ( you can see the resonance frequency of the helmholtz resonator by finding the minimum between the two peaks of the bass speaker ), especially in combination with a low frequency low-pass, like for analog subwoofer or integrated woofer layouts. You can hear the difference directly for voices, as some singers will definitely and immediately loose a couple of pounds of overweight with a simple R-L-C impedance compensation ....
Christian
matroska project admin
Vast differences in L and C might result in audible effects - but the differences of real-world speaker cables are never going to be vast enough. This has been blind and double blind tested many times in the past.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=297427")
The reason I brought it up was that a friend of mine tested a couple of "high end" speaker cables in a local hifi store and found a couple of designs have extremely high C values. If his measurements are correct (will try dig up the raw data and post it here) they suggest that some cables will have an audible effect.
After posting, however, I re-read Rod Elliot's article ([a href="http://sound.westhost.com/cable-z.htm]Loudspeaker Cable Characteristic Impedence[/url]) on the matter. He has made some reliable measurements and calculations. The results presented in the article suggest that even the expensive esoteric crap will not have an audible effect.
Speaker cable without audible effect :
http://www.hydrogenaudio.org/index.php?sho...=0entry142650 (http://www.hydrogenaudio.org/index.php?showtopic=14082&st=0&#entry142650)
Speaker cable with audible effect : next page in the thread above.
Just wanted to say "thanks" for this test. I hope that, with all the work involved, you also had some fun listening to nice recordings on high quality equipment.
The agressor signals are electric-magnetic waves. Waves with only a magnetic or only an electric field don't exist. Kill the electric part, kill all.
[a href="index.php?act=findpost&pid=297256"][{POST_SNAPBACK}][/a]
[Slightly off-topic: is there a way to shield audio equipment from cell phone interference? Can this problem be eliminated by using high-end equipment (and, of course, properly shielded cables)?]
LoL, someone made the horrible mistake of trying to post this over at Head-Fi in the cable forum.
[a href="index.php?act=findpost&pid=297387"][{POST_SNAPBACK}][/a]
Could you post a link, please? (so we can all have a laugh)
Nice test, i love it.
You could argue the listeners were not trained well enough or had bad ears,
Well, they all passed Phase I -- they all *thought* they heard a difference. So you'd have to propose that that not passing Phase 2 means, the difference they *thought* they heard wasn't real, but there's still *another* difference they didn't hear. The thing is, that can always be proposed, as long as results remain null.
but it certainly proves that any difference, if present, is not at all clear for everyone to hear. A nice additional test might be to setup a high end mic & recording system and analyse the data, it'd be interesting to see if there are inaudible differences between cables. And if so how cheap a cable can be and still perform exactly like the expensive ones.
With a €25k audio setup it doesn't hurt to spend more than €2,30 on audio cables though as you'll want some physical durability and the cost will still be a tiny fraction of the total setup.
[a href="index.php?act=findpost&pid=297099"][{POST_SNAPBACK}][/a]
Or buy/build and ABX box, so that cable switching was faster.
I think the take home lesson is that, when buying interconnects, go for a decent quality shielded cable with good plugs - anything more than that and you are wasting your money.
[a href="index.php?act=findpost&pid=297402"][{POST_SNAPBACK}][/a]
From my experience, the plugs make a huge difference. I'd always try to have golden plugs because metal plugs tend to corrode. Headphone plugs (6,3mm) are often very bad.
[Slightly off-topic: is there a way to shield audio equipment from cell phone interference? Can this problem be eliminated by using high-end equipment (and, of course, properly shielded cables)?]
[a href="index.php?act=findpost&pid=297817"][{POST_SNAPBACK}][/a]
The room within a closed metal case is always free from waves like the ones from cell phones. If I recall correctly, then holes in the case must be smaller than the wavelenght of the waves to be excluded. (Please someone confirm or deny ?) E.g. a coaxial cable with infinite lenght and perfect shield (zero resistance) has zero interference. (Faraday-cylinder)
The validity of ABX testing for audio equipment is questioned in the following article:
http://www.stereophile.com/news/050905debate/ (http://www.stereophile.com/news/050905debate/)
This article is currently displayed on the home page of the Stereophile website.
Lest there be any question, I am the author.
jason victor serinus
The validity of ABX testing for audio equipment is questioned in the following article:
http://www.stereophile.com/news/050905debate/ (http://www.stereophile.com/news/050905debate/)
This article is currently displayed on the home page of the Stereophile website.
Lest there be any question, I am the author.
jason victor serinus
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=298375")
Anyone can 'question' something... providing evidence that the questions are valid, is another matter altogether....one that Stereophile hasn't adequately addressed. The argument Mr. Atkinson presented in the debate would convince no scientist that ABX testing was an invalid method for audio equipment.
Mr. Serinus also wrote the Secrets of Home Theater article onthe power cord test...the results were negative for difference there too (there's an HA thread about it). He 'questioned' the results there too on several grounds (some valid, some not)...leading his editor to insert a postscript affirming that ABX tests *do* work.
[a href="http://www.hometheaterhifi.com/volume_11_4/feature-article-blind-test-power-cords-12-2004.html]http://www.hometheaterhifi.com/volume_11_4...ds-12-2004.html[/url]
Here is a link to Mr. Serinus' website, describing his work in holistic healing. I leave it to the reader to judge his ability to evaluate scientific methods:
http://www.planeteria.net/home/whistler/pages/healing.html (http://www.planeteria.net/home/whistler/pages/healing.html)
The validity of ABX testing for audio equipment is questioned in the following article:
http://www.stereophile.com/news/050905debate/ (http://www.stereophile.com/news/050905debate/)
This article is currently displayed on the home page of the Stereophile website.
Lest there be any question, I am the author.
jason victor serinus
[a href="index.php?act=findpost&pid=298375"][{POST_SNAPBACK}][/a]
Quoting from your article ...
But tests can neither adequately describe nor convey everything we hear, sense and feel.
That's right ... you don't feel the same way every day so you definitely cannot expect to 'sense' music the same way every day. A shiny, chrome-plated and expensive 'high-end' tube amplifier (with electrical parameters that any japanese electronics engineer would be ashamed of if any of his devices would show these) might sound very pleasant to you on one day ... another day, it might prove to sound 'dirty' whereas the 'boring' jet-black japanese 500$ MOSFET integrated amp might be your favourite of the day ... simply according to the mood you're in.
We all agree on the fact that 'hearing' music must be learned first ... since it is not an ability that you were born with. Thus, concentration abilities will influence your hearing
Objective and scientific blind testing simply rules out your daily mood ... that's why it is so important. Additionally, ABX does not natively allow you to determine which test object sounds 'better' (you'll need something like ABC/HR for that) ... it's just about finding differences on a valid statistical basis without knowing which device is actually playing. The ABX protocol sometimes simply is overrated.
The main problem (to me) that lead to the situation we face today is that HiFi magazines throughout the world are mostly exaggerating on a high level when testing equipment ... describing tonal differences with different speakers is easy ... but whenever they bring up the terms 'sounds more musical' or 'fast sound' (there are literally thousands of these), I need to ask myself what these people are actually writing about.
... but whenever they bring up the terms 'sounds more musical' or 'fast sound' (there are literally thousands of these), I need to ask myself what these people are actually writing about.
[a href="index.php?act=findpost&pid=298388"][{POST_SNAPBACK}][/a]
It's the old issue - "sounding better" vs. "sounding more transparent". Most people mix up those two or think its the same, although it is not.
I guess we can all agree that it is just natural that people prefer a certain "coloring" of the sound. Thats an absolutely reasonable and valid wish. The question however is "where" should the coloring happen? Do you want it "hardcoded" into your speakers? Or wouldn't it instead a better idea to demand that the equipment shall sound as transparent as possible, and you then can color the sound on-the-fly with EQs and DSPs?
Playback and recording -equipment should be as transparent as possible - if you want "coloring" then thats the job of "postprocessing" (EQs, DSPs, etc.).
my 2 cents,
- Lyx
Or buy/build and ABX box, so that cable switching was faster.
[a href="index.php?act=findpost&pid=298154"][{POST_SNAPBACK}][/a]
No, because we are testing the hypothesis that any standard plug or wire will destroy the sound, and that only ultra-expensive ones can transmit the signal unaltered.
Introducing an ABX box with standard interconnects in the path of the signal is a valid procedure only if we first assume that standard interconnects don't spoil the sound, in other words, if we first assume that the tested hypothesis is wrong !
krabapple: ad hominem arguments rarely do anything to address the issue at hand.
Jason: Correct me if I'm wrong on this, but I see three main points in your article raised against the practicality of ABX testing. I have a response that applies to all of them, but I'd first like to point out each one individually in case I misinterpreted something and you'd like to set the record straight. The italics are just there to separate what I perceive your arguments to be from my responses; I'm not trying to assign quotes to you.
- The emotional response to some sections of music is influenced by the music leading up to them and even if the specific sections are not possible to ABX, one piece of equipment may produce a better overall effect than the other. ABXing the full effect is impossible because the entire thing takes too long for a scientific test. This one I actually don't have a specific response to. I can't see how one would prove that just testing clips is fine without comparing a clip test to a test of the entire thing, which I would agree takes entirely too long.
- Participating in an ABX test places one in circumstances sufficiently different from normal listening that one may lose one's ability to notice subtle differences. It is true that an ABX test could affect one's listening abilities, but I'm not convinced that this effect would be enough to separate the test from, "normal," listening. Obviously, if someone went into a test expecting not to hear a difference, then there would be some question to the validity of their test if they came back with a null result, but aside from that one issue, people can be in a variety of emotional states outside of testing, as JeanLuc posted. If you evaluate one amplifier after getting a promotion at work, then evaluate another after your dog gets run over by a truck, any differences you noted between the two in a convential audiophile magazine writeup would be suspect. The results of a blind listening test aren't going to be any less reliable than results found outside of one.
- Music is a very emotional and subjective thing and therefore cannot be properly judged within a scientific test. I gave a blunt one-line reply to this point in a thread (http://www.hydrogenaudio.org/forums/index.php?showtopic=33970) here on HydrogenAudio about the article being referenced. ABX tests rely on the listener to make the decision as to whether two things sound different, not frequency response graphs or distortion measurements. Whether the emotional response to music can be measured with a microphone or not is irrelevant to ABX testing because the instruments used in an ABX test are still a very subjective human mind and pair of ears.
Finally, I'd like to say something about ABX testing with regard to buying audio equipment. When making a purchasing decision, you have to consider the differences that you
know you're going to experience outside of audibility, like whether you think one looks more impressive than the other or whether one costs more than the other, along with how different the two pieces of equipment sound. If you can't ABX two things after several trials, there's at least a good chance that you aren't going to really hear a difference in regular listening. In that case, I think it would be better to mostly ignore the issue of whether one sounds better than the other when deciding which to buy and focus on how the other things fit together. Regarding the anecdote John Atkinson gave in the debate about how even though he couldn't ABX two amplifiers, he hated listening to one (I think it might've been a third) and noticed an immediate improvement when switching to another. In this case, I think it would be valid to say that he enjoyed the other amplifier more, but saying that this is sufficient evidence that the two amplifiers were audibly different is a stretch. There's nothing to prove that he wouldn't have had a similar change from hate to love if he'd started with the more expensive amplifier and then replaced it with the cheaper one, or that printing off a picture of the more expensive one and taping it to the front of the cheap one wouldn't have made him like it. There's a lot more uncertainty to subjective testing than ABX testing (hence the term, "subjective") and I think that if someone is trying to decide which of two pieces of audio equipment would be better for them to buy or for them to recommend to others, one should try to remove as much of this uncertainty as possible.
Note added after previewing: Normally, I try to proofread what I've typed before posting it, but in this case, I think I'm going to make an exception...
Or buy/build and ABX box, so that cable switching was faster.
[a href="index.php?act=findpost&pid=298154"][{POST_SNAPBACK}][/a]
No, because we are testing the hypothesis that any standard plug or wire will destroy the sound, and that only ultra-expensive ones can transmit the signal unaltered.
Introducing an ABX box with standard interconnects in the path of the signal is a valid procedure only if we first assume that standard interconnects don't spoil the sound, in other words, if we first assume that the tested hypothesis is wrong !
[a href="index.php?act=findpost&pid=298442"][{POST_SNAPBACK}][/a]
Then your DBT will always be open to criticism that it was insensitive to real difference due to the length of the switching interval.
You could instead use the subjective 'best' cable (determined by sighted listening) as the ABX-->preamp cable, and switch between two cables as input. Or use two inputs in the preamp, from two identical source units, using different cables for each input.
I didn't say it would be easy
krabapple: ad hominem arguments rarely do anything to address the issue at hand.
Sir, I have addressed the issue at hand numerous times in numerous forums. And Mr. Serinus quite likely posted here in response to pointers I placed on other audio forums, to this thread, so I feel personally responsible to provide some background.
Personally as a scientist, when confronted with anti-science -- whether it be standard high-end audio journalism, or 'intelligent design' arguments in a Kansas courtroom -- I find it informative to know where the poster is coming from, intellectually...to place a person's claims in some sort of context. I have to wonder whether someone who has embraced New Age healing can really be swayed by scientific arguments at all. I'm also pretty sure Mr. Serinus has encountered them before, on other forums.
Do you think Mr. Serinus' *article*, if posted here (versus just a link to it) would likely have passed TOS muster?
Personally as a scientist, when confronted with anti-science -- whether it be standard high-end audio journalism, or 'intelligent design' arguments in a Kansas courtroom -- I find it informative to know where the poster is coming from, intellectually...to place a person's claims in some sort of context. I have to wonder whether someone who has embraced New Age healing can really be swayed by scientific arguments at all.
[a href="index.php?act=findpost&pid=298501"][{POST_SNAPBACK}][/a]
While you *may* be right in this case, i dont think one can generalize this. For example, i myself am very interested into spirituality(however, this does not mean that i'm open to any kind of occult BS) and do believe that there is another plane besides of the material one. But i can differentiate when one or the other is useful or efficient. On the topic at hand(and most topics on ha.org) i think the scientific approach is more efficient, because the subjective one would be too error-prone. Engagement in "un-scientific" practices and philosophies does not automatically exclude scientific thinking and abilities. But it can be the case(and often is).
- Lyx
Introducing an ABX box with standard interconnects in the path of the signal is a valid procedure only if we first assume that standard interconnects don't spoil the sound, in other words, if we first assume that the tested hypothesis is wrong !
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A proper ABX device does not interfere with the signal directly. Ok, so there may be a few plugs and a bit of wire, but even then you can always test if the ABX switcher alters the sound by testing and switching manually. Once someone realizes that the ABX device does not audibly alter the sound, then they will realize how useful it is for objective comparisons.
John noted that Arny's PCABX protocol requires that one digitize the output. This introduces an unverified mode of testing and adds variables to the mix, first in the nature of the digitizer, which conceivably (if not indubitably) alters the original sonic data, and second in the unknown nature of the amplifier over which the digital files are played back.
This may be a valid point against PCABX (and subject to manual tests whether it makes an audible difference or not), but not against ABX tests in general.
He further asserted that while most audiophiles and reviewers audition equipment by listening to familiar music for extended periods of time on one unit, ABX involves listening to short musical snippets of often unfamiliar music on ever-changing units.
Again, you can certainly listen to familiar music for relatively extended periods of time while ABX testing. Yes, a statisitcally relevent number of tests need to be done, but this does not need to be done all at once - the test can be spread over weeks if you wanted to. If you are a music lover, then spending a significant amount of time listening to music doesn't seem to be too much of a demand?
We need to do what all audiophile reviewers of worth have learned to do: trust our ears.
The best way to trust our ears is to control all of the variables except for the sound itself - that way, any differences that we hear will be real to our ears. So the only way to trust our ears is with ABX testing. Anyone who does not like the objectivity of ABX testing obviously does not trust their ears.
Remember, the ABX procedure itself does not judge the differnece in sound (that is left to the listener), but it enables us to verify if the differences we are hearing are real.
The crazy thing about this ongoing debate is that listening to music is not a rational, scientific phenomenon. Who knows where the music that a composer puts on paper actually comes from, let alone the source of the inspiration with which musicians bring those notes to life? Can you explain why one interpretation of a classic song moves you to tears and another leaves you cold? Can you scientifically explain what makes your heart skip a beat?
Of course not. And since audio components and cables are nothing more than electrical conduits for that which lies beyond words and reason, how can we expect charts, graphs, and short bursts of preselected tones to tell us everything about how a component will affect us, let alone how it will interact with other components in a given listening environment?
One thing is certain: Music is music, and protocols are protocols. ABX may be a valid testing protocol for laboratory equipment, but when you bring auditory sensation, emotional reaction, and other, at best, only partially understood mechanisms of brain response into the equation, you are pretending that you can objectively test that which you cannot adequately explain. And please, please don't try to convince me that because you can't fully explain something or detect it with scientific instruments, it doesn't exist. Better to sell me the Brooklyn Bridge.
This is precisely why ABX testing is important. ABX lets us verify that the supposed audible differences between two components is real or not, without letting any other variables (some of which we may not yet understand) interfere with the result.
PS, many of the questions posed in the above quote are in fact being studied by scientists...
The article is obviously biased in that it keeps mentioning the word "absolute" to sway the reader. It is clear that the author is missing the point of science and objective testing. Science is not about absolute certanty, it is about highly probable outcomes. As science progresses, scientists develop more and more probable (in terms of accuracy) theories. For a theory to be of high probability, it has to be consistent with all scientific observations. The scientific method is used to control all of the variables except for the one that you are trying to test - so there is a high probability of the cause leading to the effect.
A theory does not have to be
absolutely correct for it to be useful in the real world. Using a highly probable theory is far more useful than a theory with a much lower probability.
ABX should be used to determine whether there actually is an audible difference between two components, as the results of an ABX test are far more likely to be correct than a single sighted AB comparison.
But if you believe that there is no difference between your (potentially flawed) perceptions and reality, then I believe there is an opening for you in the Oceania outer party.
Besides all this discussion, there's a thing that Pio's test clearly proves and that was already well known: that our perception and reaction to sound is easily influenced by our mind even in unpredictable ways. In other words, we (I guess some people more than other) easily tend to hear differences where there are none. Remember, in this test, people really heard differences. But those differences didn't exist in reality. It was just their mood, subsconcious bias, beliefs, or other factors , that made them feel that some supposed cable sounded better than other.
But high-end proponents always ignore this basic fact as a key factor for invalidating their way of evaluating audio equipment. Blind tests, even if they had shortcomings (which is up to discussion), are so far the most realiable way of analyzing real differences in sound.
Said this, I think there's nothing against people buying equipment that makes them feel the music better, even when that enjoyment comes more from the placebo-effect side of the equipment than the actual sound they produce. Of course, in a serious discussion about these issues, both effects should be acknowledged and analyzed by separate.
Then your DBT will always be open to criticism that it was insensitive to real difference due to the length of the switching interval.
I adress this issue with phase 1 and 2.
In phase 1, listeners look for an audible difference. They decide the switching interval so that the difference is audible.
In phase 2, they check that this difference is real, before starting the test.
You could instead use the subjective 'best' cable (determined by sighted listening) as the ABX-->preamp cable, and switch between two cables as input. Or use two inputs in the preamp, from two identical source units, using different cables for each input.
I didn't say it would be easy
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Using a cable for the ABX->preamp interconnect is not a good solution. The ABX switcher can mask differences between the cables.
Using two identical sources might be a solution. However it was criticized because the cables would interfere with each other. Some cables are designed to kill stationary waves caused by external influences. If they are compared to standard cables plugged into the same device, the standard cable can receive that radiofrequency and inject it into the other cable.
A proper ABX device does not interfere with the signal directly.
Then ABXing cables makes no sense.
you can always test if the ABX switcher alters the sound by testing and switching manually. Once someone realizes that the ABX device does not audibly alter the sound, then they will realize how useful it is for objective comparisons.
I'm pretty sure that any hardcore audiophile would "hear" the switching box altering the sound. You know, I've been told over and over by all audiophiles that it was impossible to listen to a hifi system before buying it if a switch was in the path of the signal.
In order to prove that the ABX switch is transparent, we need to show that it is not ABXable itself. Thus we need to run an ABX test where it will be plugged and unplugged between each playback. Since this is unavoidable, let's save time and apply directly this procedure to the cables.
But actually, it's worse than this : two people already stressed that the 1500 € Marantz SACD player was too poor to reveal the sonic differences between the cables, and that we should have used the Acuphase one instead.
That's why the real solution is to invite hardcore audiophiles to take part to phase 1. We were no hardcore audiophiles, and our first reaction, at the beginning of phase 1, was that all the cables sounded the same. I must admit that the differences that we believed to hear after this in phase 1 and 2 were only caused by our desire to hear something altogether.
This wouldn't spoil statistics. Phase 3 has not started yet. Technically, the test is still running in phase 2. And jumping between phases 1, 2 and 3 is not forbidden as long as results given in phase 3 are permanent, and the number of trials and listeners of phase 3 are not changed after one result of phase 3 at least is known.
Then your DBT will always be open to criticism that it was insensitive to real difference due to the length of the switching interval.
I adress this issue with phase 1 and 2.
In phase 1, listeners look for an audible difference. They decide the switching interval so that the difference is audible.
In phase 2, they check that this difference is real, before starting the test.
Yes, but one could be *really picky*, and suggest that you havent' ruled out that there is still a *real difference* that went undetected, because of the switching interval effect. Certainly in an actual scientific experiment, there would be an attempt to reduce the switching intervals to be essentially instantaneous, to avoid this sort of criticism. It's tedious but necessary if you want to make the case airtight.
You could instead use the subjective 'best' cable (determined by sighted listening) as the ABX-->preamp cable, and switch between two cables as input. Or use two inputs in the preamp, from two identical source units, using different cables for each input.
I didn't say it would be easy
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Using a cable for the ABX->preamp interconnect is not a good solution. The ABX switcher can mask differences between the cables.
LOL. In terms of pickiness, that's the same sort of objection as I raise above.
Using two identical sources might be a solution. However it was criticized because the cables would interfere with each other. Some cables are designed to kill stationary waves caused by external influences. If they are compared to standard cables plugged into the same device, the standard cable can receive that radiofrequency and inject it into the other cable.
And again..
Certainly the switching interval effect (the result of limits on audible memory) is *real* and has been documented, while these other effects seen speculative. So why are you worried about one and not the other?
A proper ABX device does not interfere with the signal directly.
Then ABXing cables makes no sense.
? A properly designed passive switch should have no sonic effect on the inputs and outputs, other than the switching.
you can always test if the ABX switcher alters the sound by testing and switching manually. Once someone realizes that the ABX device does not audibly alter the sound, then they will realize how useful it is for objective comparisons.
I'm pretty sure that any hardcore audiophile would "hear" the switching box altering the sound. You know, I've been told over and over by all audiophiles that it was impossible to listen to a hifi system before buying it if a switch was in the path of the signal.
In order to prove that the ABX switch is transparent, we need to show that it is not ABXable itself. Thus we need to run an ABX test where it will be plugged and unplugged between each playback. Since this is unavoidable, let's save time and apply directly this procedure to the cables.
But actually, it's worse than this : two people already stressed that the 1500 € Marantz SACD player was too poor to reveal the sonic differences between the cables, and that we should have used the Acuphase one instead.
You're surprised by such a response?
That's why the real solution is to invite hardcore audiophiles to take part to phase 1. We were no hardcore audiophiles, and our first reaction, at the beginning of phase 1, was that all the cables sounded the same. I must admit that the differences that we believed to hear after this in phase 1 and 2 were only caused by our desire to hear something altogether.
This wouldn't spoil statistics. Phase 3 has not started yet. Technically, the test is still running in phase 2. And jumping between phases 1, 2 and 3 is not forbidden as long as results given in phase 3 are permanent, and the number of trials and listeners of phase 3 are not changed after one result of phase 3 at least is known.
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Pio, I think your test was great. But now you know the sorts of quibbles that you can expect to encounter.
Yes, but one could be *really picky*, and suggest that you havent' ruled out that there is still a *real difference* that went undetected
That's right. However, the differences ruled out are larger and larger.
We showed that some skeptics (Emmanuel Piat and me), and some unconvinced people (Marsupilami and JC07) could be lured into hearing things if they force themselves to look for differences between sources that seem identical to them at first sight.
That's completely different than proving that someone absolutely certain to pass the test because differences are so huge that they can't be missed, can fail.
Certainly in an actual scientific experiment, there would be an attempt to reduce the switching intervals to be essentially instantaneous, to avoid this sort of criticism.
I didn't get this critisism at all. 99% of audiophile people acknowledge that all cable sound the same when switched quickly (Edit : interconnect cables without RLC filters). There is no debate about this fact. One of the main criticism was exactly the opposite : the listening sessions were too short ! The majority of audiophile who believe in cables say that the differences can only be heard after a long time, usually several days of use (not burn-in, but just hearing adaptation from the listener).
A long-term test have already been proposed with listening sessions of one week each in the workgroup I created in homecinema-fr.com. The listener accept to have his cables hidden at home. Someone visits him, and is left alone in the room. He does something, or not. The listener can listen during the whole next week to decide if the cable have been changed. I'll be able to provide the statistic analysis for them if they find some listeners to start the test.
I know that scientifically, this kind of test have near 100 % of chances to fail, but that's not what audiophile believe.
Certainly the switching interval effect (the result of limits on audible memory) is *real* and has been documented, while these other effects seen speculative. So why are you worried about one and not the other?
As I said, it spoils the test, because obvioulsy, one cannot prove somthing if he assumes that this thing is wrong in the hypothesis on which his demonstration is based.
When I test something, I must have the decency to read the instruction manual. For exemple, the cables tested had a direction. Audiophiles say that these cables, plugged in the right direction, sound better than standard ones. I want to see if this is right or wrong. Not if audiophile cables plugged in the wrong direction sound better than stadard ones. Audiophile never said that expensive cables sounded better than standard ones in the wrong direction. There is no need to test it. Everyone agrees on this.
In the same way, no audiophile pretends that high end cable sound better than standard cables when an ABX switcher is plugged in the middle of the path of the signal. I'm not going to test this. All I want to test is audiophile claims, and this is something that no audiophile claims.
Actually, it is very probable that the cable manufacturer himself would dismiss that use of his cable. Testing a device, I must use it as it is intended to be used. Otherwise I'm not testing its claimed properties.
Sir, I have addressed the issue at hand numerous times in numerous forums.[a href="index.php?act=findpost&pid=298501"][{POST_SNAPBACK}][/a]
I didn't mean to suggest that you haven't.
And Mr. Serinus quite likely posted here in response to pointers I placed on other audio forums, to this thread, so I feel personally responsible to provide some background.
Personally as a scientist, when confronted with anti-science -- whether it be standard high-end audio journalism, or 'intelligent design' arguments in a Kansas courtroom -- I find it informative to know where the poster is coming from, intellectually...to place a person's claims in some sort of context. I have to wonder whether someone who has embraced New Age healing can really be swayed by scientific arguments at all. I'm also pretty sure Mr. Serinus has encountered them before, on other forums.
If the arguments he presented in the article were new ideas that he and maybe a few other people were coming out with, then I would agree that his background would be something that should be considered; however, since I've heard everything he said in that article from other people advocating subjective testing over ABX testing, I don't think questioning his background is a good way to meet his objections. If he followed you here from some other board where you gave direct responses to all of his claims, well, then I'm sorry for singling out your one post.
Do you think Mr. Serinus' *article*, if posted here (versus just a link to it) would likely have passed TOS muster?
No.
i use just some Composite Video cables that came bundels with some GFX card at my work.
Its same plugs as the normap phono cable, but now left/right are seperate to differet cables and there is some kind of shielding.
but i only do this because they where free :-)
Very nice test. Good work!
Certainly in an actual scientific experiment, there would be an attempt to reduce the switching intervals to be essentially instantaneous, to avoid this sort of criticism.
I didn't get this critisism at all. 99% of audiophile people acknowledge that all cable sound the same when switched quickly (Edit : interconnect cables without RLC filters). There is no debate about this fact. One of the main criticism was exactly the opposite : the listening sessions were too short !
<snip more of same>
I think there's a misunderstanding here. Shortening the switching *interval* does not mean that the listening sessions have to be short! What I mean by swithcing interval, is the time it takes to *change* from cable A to cable B...not the time it takes to listen to them. (I would call that the 'listening interval')
Short switching intervals are more sensitive because audio 'memory' only remains accurate for details for a short time.
direction sound better than stadard ones. Audiophile never said that expensive cables sounded better than standard ones in the wrong direction. There is no need to test it. Everyone agrees on this.
I think you need to be careful about claims of 'audiophiles never said'. Audiophiles have said *A LOT* of kooky things in my experience, one being that 'direction' of the cable is important -- Robert Harley of Stereophile says this in his book. He attributees it to the crystal structure of copper or some such
pseudoscience.
In the same way, no audiophile pretends that high end cable sound better than standard cables when an ABX switcher is plugged in the middle of the path of the signal.
What makes you so sure that no audiophile ever perceived such a difference in an ABX test , Pio?
I'm not going to test this. All I want to test is audiophile claims, and this is something that no audiophile claims.
Again, what makes you so sure? Do you mean, you 've simply never *seen* such a claim?
You might want to ask guyes like Tom Nousaine or Arny Kruger about what audiophiles have claimed, when using ABX boxes. Remember that any ABX test involves first perceiveing a difference between A and B -- even when connected to the ABX box.
It's true that audiophiles might (and have) claim that an ABX box itself 'masks' differences...but if they hear differences when comparing A and B, that can't be globally true, for the same reason it wasn't true in your test: people heard differences in phase 1.
I can't tell all that audiophile have claimed. What I say only reflects the common opinion that I have gathered in different shops, in the press, among audiophile firends, and on some audiophile forums.
To put it otherwise, if a test with an ABX box fails, it leaves a valid objection for audiophiles : the box is not as transparent as the cables tested, and masks the difference.
If I let a hardcore audiophile setup everything in phase 1, and he says that the difference is huge and that I am deaf, then he can't tell after the test that the system was not transparent enough to reveal the difference.
I can't tell all that audiophile have claimed. What I say only reflects the common opinion that I have gathered in different shops, in the press, among audiophile firends, and on some audiophile forums.
To put it otherwise, if a test with an ABX box fails, it leaves a valid objection for audiophiles : the box is not as transparent as the cables tested, and masks the difference.
If I let a hardcore audiophile setup everything in phase 1, and he says that the difference is huge and that I am deaf, then he can't tell after the test that the system was not transparent enough to reveal the difference.
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The *same* objection can be made about your tests, due to the time it takes to switch cables: that your method was not as 'transparent' as one using short interval cable switching would be.
For an ABX box test that has already been performed, and whose results were null, all the audiophile can claim is that the the ABX box masked differences *OTHER THAN* the ones that were 'heard' when the subjects were comparing A and B, *using the ABX box*. People , including audiophiles, *can* and *do* hear such differences when they switch between A and B using an ABX box. If they don't, there's no reason to continue to test. Subjects have to hear differences *during* ABX box tests, in order for the test to be meaningful. And subjects do!
Just as with your test, if no one had claimed to hear difference in the phase 1 part, there would be no reason to continue. But they did claim to hear differences, and so you did continue with the test.
You have to think what this test is about. Most audiophiles don't care about the switching intervals. No audiophile uses a procedure to perform quick switching when comparing cables. They don't need it, they hear clear differences. This was a test aimed to check audiophile claims, not limits of human hearing. As such, the test was performed using usual "audiophile" procedures, except for the blind and statistics part, of course.
You have to think what this test is about. Most audiophiles don't care about the switching intervals.
Well, most of them don't care about objectively substantiating perceived differences *at all*, much less whether short or long switching intervals were used to do it!
No audiophile uses a procedure to perform quick switching when comparing cables. They don't need it, they hear clear differences. This was a test aimed to check audiophile claims, not limits of human hearing. As such, the test was performed using usual "audiophile" procedures, except for the blind and statistics part, of course.
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Points taken, but I'm playing devil's advocate -- I have lots of experience debating 'audiophiles' at this point , and I'm giving Pio a taste of the sorts of objections they could raise to his protocol, though unlike them I'm focusing only on the ones that have scientific validity -- there are a half-dozen flooby-based objections 'audiophiles' would raise too!
For my own sanity, I don't need to convince them - I just need to convince me.
Any kind of listening experience where I can hear differences one moment, but not the next - and the only thing that's changed is that I have the identity of the sound source hidden from me - that's enough to convince me that I'm imagining the differences.
I don't care what anyone else thinks about the matter!
I don't discount stranger things happening though - in one test, I could detect phase correction of a loudspeaker on a Friday afternoon, but not on a Monday morning - both times blind. Conclusion: it was either chance, or altered perception - either way, it suggested to me that it wasn't that important, but speakers should be phase linear if possible because it might be audible. If you can fix something cheaply that might be audible, do it. If you're tempted to fix something, at great expense, which you can't hear - find something better to do with your money/time/life!
Cheers,
David.
Pio2001, would it be possible to put a couple of late-incoming follow-up questions? My French is really lousy, so I can't figure out these things:
1. How long were the usual timespans between the observations in phase 1 and phase 2 respectively?
2. Was phase 2 performed on CDs only, or also on SACD media?
Thanks in advance (with no obligation)
FA
1. How long were the usual timespans between the observations in phase 1 and phase 2 respectively?
10 to 30 seconds. Shorter and shorter as Patrice improved his performance
2. Was phase 2 performed on CDs only, or also on SACD media?
On CD only.
While I'm here, I can add that there was a follow-up. Other audiophiles gathered in Toulouse in order to repeat the test in different conditions. This time, the main listener (called Rorominator) of the test was at home, listening his own CDs on his own system, with cables that he was certain he could identify without any effort. 4 other listeners joined him.
Thus the arguments about "unknown system", "unknown room", "lots of cables", and "unknown CDs" were ruled out. He also used an easier protocol. Each session was composed of two playbacks. One with the standard cable, the otrher with the audiophile one (an Ecosse cable, sold 1300 €). The order was random. Listeners had to tell which was the first cable.
Rorominator scored 9/20. But one of the 4 others scored 10/10 ! Which leads to p=0.5%
After some time, I got the detailed results from Rorominator. We discovered that they made a mistake about the score. He only scored 8/10, and not 10/10, which is p=25 % !
The lesson to learn is that it is always useful to make all the raw results available for everyone to check .
Rorominator scored 9/20. But one of the 4 others scored 10/10 ! Which leads to p=0.5%
After some time, I got the detailed results from Rorominator. We discovered that they made a mistake about the score. He only scored 8/10, and not 10/10, which is p=25 % !
Yeah, yeah - "sure to be able to identify" and then 9/20. This test satisfies. What about the scores of the three remaining folks ?
Thanks. I was thinking of a similar test together with a friend who ended up with two DVD players after a messy guarantee repair :-). I'm not yet sure I can lure this guy into this. But just in case, I would appreciate feedback on the methodology I have in mind:
1.- Identical CDs, i.e. same edition of an album well known by the participants.
2.- Mid-end speakers and stereo amplifier, well known by the owner, but not by me.
3.- Identical upper Low-end CD/DVD-player, i.e. same brand and model, delivered same year.
4.- Lower Mid end cable pair + Unbranded cable pair.
5.- Test person leaves room. Random connection of players to amp. Left player always connected to Input 1, Right player to Input 2. But which cable pair goes where is decided by flip of coin.
6.- Test person returns, and compares players Left and Right by listening and switching freely for X minutes. Scores cable pairs as "better" and "worse" by some predefined criterias.
7.- Steps 5 and 6 are repeated until sample size N is reached.
8.- Test is repeated with me as test person and my friend as "investigator".
Thanks in avance
FA
What about the scores of the three remaining folks ?
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All links : [a href="http://www.homecinema-fr.com/forum/viewtopic.php?t=29786006&postdays=0&postorder=asc&start=255]http://www.homecinema-fr.com/forum/viewtop...r=asc&start=255[/url]
All scores :
Rorominator (home listener) : 9/20
Abricot : 8/15
Nolwenn : 6/15
Phoenix_prt : 8/10
Usa_satriani : 3/5
which cable pair goes where is decided by flip of coin.[a href="index.php?act=findpost&pid=313670"][{POST_SNAPBACK}][/a]
Ok.
Rather use a dice if you can. Flipping a coin can give weird results according to the way it is flipped.
Best : a certified dice with a dice cup (available in Backgammon specialized shops).
6.- Test person returns, and compares players Left and Right by listening and switching freely for X minutes. Scores cable pairs as "better" and "worse" by some predefined criterias.[a href="index.php?act=findpost&pid=313670"][{POST_SNAPBACK}][/a]
I don't think that demanding an aswer after a limited time is a good idea. If the test fails, you leave the tester with valid objections (time too short, conditions too difficult, bad mood...), and you can't run the test again without introducing very complicated influences in the calculus of the success or failure.
By giving unlimited time, or giving limited time, but allowing null answers, that will be left out and won't increase the number of completed trials, you leave no excuse for the listener in case of failure.
7.- Steps 5 and 6 are repeated until sample size N is reached.[a href="index.php?act=findpost&pid=313670"][{POST_SNAPBACK}][/a]
If the test is between interconnects, I think it would be safer to put it in perspective with the previous tests, as far as mathematical analysis is concerned. Which means that we should take into account the occurence of one failure already (the very first test, that started this thread, did not pass the training phase, so no failure occured).
The target value for p should be very low, because interconnects having an audible effect is very improbable, and p should always be very inferior to the probability of the positive hypothesis to be right (otherwise, the success by chance will be obviously considered as more probable than the positive hypothesis !)
p < 0.001 should be the maximum, IMHO. It would be interesting to leave some room for very low p. Like p < 0.00001 in case of a perfect test, and p being still < 0.001 if some isolated errors creeps in.
Since one test already failed, these values should be decreased. I don't think that anyone ever calculated the factor by which p should be decreased after each failure in case of a sequencial test. I don't even know if it is possible for the general p of a sequencial test to converge towards a limit value if the local p of each session in divided by a factor k from session n to session n+1. If it was the case, computing the limit value from the starting local p and the factor k would be a very, very useful thing for the community.
Contrary to our tests, where all listeners were listening together, there won't be possible influences between your answers and those of your friends. So you've got the choice.
You can sum up all answers, and compute the general resulting p value, which allows you to perform half as much trials as if you were testing alone. In short, you perform half the test, and your friend performs the other half.
The problem is that if one of you fail, and the other succeeds, the result will be a failure ! Since one of you only is familiar with the listening setup, it's better to leave both of you the possibility to win.
Thus your success condition will be "one listener at least gets a success with a probability of guessing inferior to p1". Then you can calculate the probability p2 of this condition to occur by chance. It will be the real p of your test.
You won't be allowed to sum up both your results. If you both fail, but that the sum of your answers is a success, forget it, the test failed altogether.
If you want to leave the door open for all possible successes, induvidual and collective, then you'll have to do more maths in order to setup the right number of sessions, and compute the real general result of the test.
The agressor signals are electric-magnetic waves. Waves with only a magnetic or only an electric field don't exist. Kill the electric part, kill all.
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[Slightly off-topic: is there a way to shield audio equipment from cell phone interference? Can this problem be eliminated by using high-end equipment (and, of course, properly shielded cables)?]
LoL, someone made the horrible mistake of trying to post this over at Head-Fi in the cable forum.
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Could you post a link, please? (so we can all have a laugh)
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Sorry for such a late reply! I visited "Head-Fi's" "Cable" forum just to see if these fanatics really exsist... I mean really, I've never actually herd of someone believing cables needed a "break-in" period!
Alas, its true, here's the first thread I came across!
[a href="http://www6.head-fi.org/forums/showthread.php?t=127774]Link[/url]
It's amazing there is even a forum for something that doesn't make a bit of difference. Imagine HA having a filename forum where people discuss filenames with the best harmonic bit patterns that increase the karma of the rest of the audio file, for much clearer whateverness.
There isn't a cables forum, although one of the forums includes any discussion about cables.
For me engaging in a heated debate about cables seems a strange thing. But each to his own.
While I'm here, I can add that there was a follow-up. Other audiophiles gathered in Toulouse in order to repeat the test in different conditions. This time, the main listener (called Rorominator) of the test was at home, listening his own CDs on his own system, with cables that he was certain he could identify without any effort. 4 other listeners joined him.
Thus the arguments about "unknown system", "unknown room", "lots of cables", and "unknown CDs" were ruled out.
Rorominator scored 9/20.
I'm really genuinely curious to hear what was his reaction (excuse) to that failure.
Some people do change their mind after revelation. Thats a sign of intelligence.
He said that he didn't have any excuse for failing !
However, he's still around in cable discussions, and still pretends that sonic differences between cables are very important, like Jason Victor Serinus, still advocating the use of 1000 € power cables after the utter failure of the blind test that he himself organized : http://www.hometheaterhifi.com/volume_11_4...ds-12-2004.html (http://www.hometheaterhifi.com/volume_11_4/feature-article-blind-test-power-cords-12-2004.html) (hey, look, a forum entierely about cables http://www.hometheaterhifi.com/forum/showt...48&page=4&pp=10 (http://www.hometheaterhifi.com/forum/showthread.php?t=1448&page=4&pp=10) )
He said that he didn't have any excuse for failing !
However, he's still around in cable discussions, and still pretends that sonic differences between cables are very important, like Jason Victor Serinus, still advocating the use of 1000 € power cables after the utter failure of the blind test that he himself organized : http://www.hometheaterhifi.com/volume_11_4...ds-12-2004.html (http://www.hometheaterhifi.com/volume_11_4/feature-article-blind-test-power-cords-12-2004.html) (hey, look, a forum entierely about cables http://www.hometheaterhifi.com/forum/showt...48&page=4&pp=10 (http://www.hometheaterhifi.com/forum/showthread.php?t=1448&page=4&pp=10) )
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When I read your first line I thought, great, another that has seen the light! But alas, no, another that still has his head in the sand.
It's amazing there is even a forum for something that doesn't make a bit of difference. Imagine HA having a filename forum where people discuss filenames with the best harmonic bit patterns that increase the karma of the rest of the audio file, for much clearer whateverness.
Personally, as far as Karma for my music goes, my prefered cable is USB.
Thanks for the advices Pio2001. Regarding the maths, I thought of chi-square on null hypothesis "There is no difference between cable pairs". AFAIK 9/10 is actually a quite strong argument for rejecting H0.
Test person's wife is now heading for a month of playa, let's see if we're lucky. I also think I've found a way to use non-recoded 96 KHz audio...
Cheers
FA
Thanks for the advices Pio2001. Regarding the maths, I thought of chi-square on null hypothesis "There is no difference between cable pairs". AFAIK 9/10 is actually a quite strong argument for rejecting H0.
Test person's wife is now heading for a month of playa, let's see if we're lucky. I also think I've found a way to use non-recoded 96 KHz audio...
Cheers
FA
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I don't know chi-square. I learned the maths of blind tests reading this forum.
By 9/10, do you mean 9 right answers out of 10 for a question with two choices ?
It means p < 1.08 %
For someone who thinks that it is impossible for two cables to sound different, it is still 1 %, thus not impossible to get it by chance. The result will have to come with a very detailed description of how the tests went, in order to check that there were no rejected bad answers because the listener wanted to try a different CD, for example, or because the test was restarted in quieter conditions after the dog was alseep...
Thanks for the advices Pio2001. Regarding the maths, I thought of chi-square on null hypothesis "There is no difference between cable pairs". AFAIK 9/10 is actually a quite strong argument for rejecting H0.
Test person's wife is now heading for a month of playa, let's see if we're lucky. I also think I've found a way to use non-recoded 96 KHz audio...
Cheers
FA
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I don't know chi-square. I learned the maths of blind tests reading this forum.
By 9/10, do you mean 9 right answers out of 10 for a question with two choices ?
It means p < 1.08 %
For someone who thinks that it is impossible for two cables to sound different, it is still 1 %, thus not impossible to get it by chance. The result will have to come with a very detailed description of how the tests went, in order to check that there were no rejected bad answers because the listener wanted to try a different CD, for example, or because the test was restarted in quieter conditions after the dog was alseep...
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Is 10 trials really enough to make a robust claim, regardless of the score?
Rather use a dice if you can. Flipping a coin can give weird results according to the way it is flipped.
Best : a certified dice with a dice cup (available in Backgammon specialized shops).
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Perhaps easier would be to use a true random number generator like [a href="http://www.random.org]random.org[/url] which uses atmospheric noise to generate numbers - pretty much as random as you can get. Set it to generate integers between 1 and 2, a result of 1 being cable location x and 2 being cable location y. There's also HotBits (http://www.fourmilab.ch/hotbits/) which uses radioactive decay to generate random numbers, which is also extremely unpredictable.
To get back on the original topic - testing cables, I do find the test very useful. We all knew it, but it is always good to get it straight.
One thing I was wondering is if we could maybe test the shielding of the cable. At home I had to burry my audio cables along with USB, SVIDEO, SPDIF (coax), Antenna and some speakers. Because I have this one place where all my cables go. I'll soon have power in there as well.
Giving that I have 10 meters of cable, I am seriously starting to wonder if a more expensive (and though supposedly better-shielded) cable wouldn't make a difference.
Any tests have been performed such as this one? wrapping a 10 meter cable around an antenna cable or a power cord and trying to abx vs a more expensive cable (or even abxing it against the same one not wrapped)?
One of the cables that I tested was not shielded. I think that we didn't listen to it, but I measured it. You can get some results in the zip file provided in the original message.
It passed all RMAA tests with exactly the same results as the standard cable exept for a 0.01 dB boost at 20 kHz. In fact, looking very closely, we can see that all cables gave 0.01 dB more than the standard one at 20 kHz.
However, these measurments were done with the DAT deck (analog input) on the floor. During previous measurments made with the deck just below the CD Player, and the cables against the wall with some power cords, the unshielded cable exhibited a louder 50 Hz component in the background noise.
Something like -86 dB instead of -100 dB. But there were also big differences between the other cables, the RG179 being below -110 dB at 50 Hz.