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Comments about Blind Testing
First I can say that I don't have much of a bias for or against any
type of speaker wire (or speaker cable system with terminations) or any low voltage interconnect cable except I'd like the former to deliver as much current as possible without changing impedence and the latter to be super well shielded and matched to the components being connected in terms the capacitative and inductive characteristics the component's designers considered appropriate when the preamp, tuner or other was designed and when it's specifications were determined. I have been given dozens of different kinds of speaker wire and cable systems to use in my CES booth displays and to be used when I did speaker selling demos in stores. 20 years of research testing loudspeakers for seller and buyers showed me that the distortions in most speakers are so huge that it becomes nearly impossible to hear any unique characteristics of speaker wire except its ability to deliver current to cone speakers and voltage to electrostatics. The very few loudspeakers that might be able to demonstrate whether there was any audible improvement using one kind or brand of wire (or even a cable system including unique terminations), like the Quad 63 have other electrical components like transformers in their systems making it seems unlikely that subtle differences in wire can be significant enough to hear. I believe this to be fact because of testing that I've done when designing loudspeaker systems for audio companies, testing done as the loudspeaker system development Imagineer for Disney during the building of EPCOT and Tokyo Disneyland, and testing I've done for the AES paper I delivered March 4, 1982 in Montreaux and later that April to the Los Angeles chapter that showed that voice coils in loudspeakers undergo so many changes of "sound reproduction capability", that hearing the difference created by different wires of the same guage and current carrying capacity would be like finding the molecules of a specific raindrop after it had fallen into the ocean. When I gave my paper on loudspeaker compression to the AES chapter in Los Angeles in April 1982 a few of the engineers in attendance calculated that the just the factors of non-constant dynamic impedence and compression changes in loudspeakers that my testing showed, would likely show up as fast variations in temperature on the voice coil in excess of 100 degrees centigrade. Almost immediately the chief engineer of Cetec-Gauss stood up to mention that while he didn't think that it had really been important to mention his company's testing in this arena up to that point in time, he could verfiy that fast changes in voice coil temperatures of well in excess of 100 degrees centigrade had been measured in many of the tests Cetec-Gauss had done on their own products and those of their competitors. These kinds of massive forces obliterate "subtle" differences. The louspeakers being discussed at that moment were large voice coil types with designs that made cooling one of the most important considerations (although I've tested hundreds of different component loudspeakers for professional and home hifi use). The loudspeakers used in home hifi systems do not cool nearly as well as pro loudspeakers, and the negative effects on sonic characteristics due to temperature change are much greater than those demonstrated by professional loudspeakers. And that is just one of the factors involved with loudspeaker compression. These changes in sonic characteristics make it nearly impossible to do any real research on speaker wires that could be relevant to audiophile listening because the test to make such comparison "fair" would be literally impossible to design. By the time listeners could focus on the sound playback of of one of the test wire/products the second product in the test would already be unfairly tested because the test loudspeaker system (acoustic microscope equivalent) will not likely "sound" the same as it did 30 seconds ago. This means that the test passage would need to be made longer and restarted after a specific cooling off time and by then the human acoustic memory is gone. This could be why so many anecdotal testimonials involve hearing "things" after the time was taken to disconnect one set of speaker wires and connect a second set. The speakers probably cooled down and sounded better after the "wire changing period". Maybe comparitive testing of large voltage wire should be done using thin film or electrostatic headphones because these devices are actually better at exposing tiny differences in audio characteristics. As an aside I might suggest that the way some speaker cable systems are produced they seem to want to be part of the crossover for the louspeaker or maybe adjust the frequency response. I've always wanted speaker wire to be able to deliver gobs of current to some of the loudspeakers I've designed or listened to, except with electrostatics when I want the speaker wire to conduct the correct voltage from the amp to the speaker's input irrespective of the changes in the input impedence of the speaker. If there really was a wire that was substantially better sonically then "super consumers" like Disney would do the testing (at whatever cost) so that they could deliver the AES papers that would make greater prestige for Disney. Disney has bought numerous "home hifi" products and tested them (and sometimes even used them) because they have an incredible investment in not only having the best of "whatever" in their facilities, but in knowing more than any other audio consumer in the world. Matsu****a may be an incredible audio manufacturer and their leaf tweeter with extended response to 80kHz is one of the few devices that can be used to test whether human hearing really processes 20+kHz information when our brain decides on how much "acoustic reality" is being reproduced. But even Matsu****a has recognized that no company is as concerned with knowing what is what in audio as much as Disney. And cost is no object for Disney, so whether speaker wire was $.50 a foot or $5.00 a foot wouldn't matter to a Disney engineer because (through AES) Disney promotes their use of the audio equipment and materials proven to be sonically superior in their theme parks. The test labs at WED Imagineering are better outfitted by Bruel and Kjaer than almost any audio manufacturer in the world. As "super-consumers", Disney is unrivalled and there isn't really much difference in speaker wire sonically or there would be Disney engineers giving papers on their "wire" findings at AES conventions. As it is, Disney has strict rules about having enough copper to carry the current or voltage to the speakers designed into any facility or show in their theme parks, but even in the most critical applications there is no special type of wire specified. It's also a sure bet that the manufacturers of wire or wiring harnesses for speakers don't really want there to ever be any one special kind of wire or wiring system that proves to be superior to others. In the audiophile marketplace, confusion about which wire is best increases sales. Otherwise it wouldn't be possible to sell the same consumers 3 or 4 different sets of wire or interconnect cable at enormous cost. And the different types of manufacturers all have their own reasons for not wanting any one type of wire to be determined "best". These reasons vary even if sometimes when confronted by an insecure retailer, a manufacturer may SAY their wire is superior or the most cost effective sonically, but like I say, "Confusion increases sales" so doing a real comparison test is the opposite of what these manufacturers want. Higher sales keep companies alive and that is their prime directive, so confusion in the marketplace best fulfills that directive. Look at all the possibilities. The wire seller who truly believes his product is superior won't want to bother wasting time, money and effort to prove something he already believes. The wire seller who knows his product is NOT superior won't want to be shown up. The wire seller who doesn't care if his product is superior won't want to bother with something as unimportant as testing, especially because of the costs involved and the possibility he MAY be shown up. So it is against the interests of wire sellers to participate in any tests which would clearly determine which speaker wire was superior or at least which was best for which speaker or for the money. Even if one crusading wire maker were to support a true test of wire it would only allow every other manufacturer to look at the results and then make a copy of the product. And that doesn't consider the great unknown that could be very deadly to any and all of the wire companies. It can happen in the most bizarre ways but the results can be quite staggering. In 1978 I was the professional products marketing manager at ESS (Electrostatic Sound Systems) at a time when they sold professional versions of the Heil tweeter, some professional amplifiers and had the rights to import some European professional products. The company took on a new ad agency for consumer products and this agency did a month of field research in 20 retail outlets to see what they had to work with for ESS' new ad/marketing campaign. The ad agency found that in head to head sales demos using ESS speakers against any other speaker brand of comparable price, store salespeople were able to sell the sound superiority of ESS loudspeakers against any other brand. With the various retailers around the country carrying various mixes of loudspeaker lines, ESS seemed to be able to sell their products against any other brand based on sound quality during a demo. Store salesmen usually take the path of least resistance and they would have sold more ESS loudspeakers except for one thing. Sometimes when store salespeople suggested to potential customers that they listen to speakers, the customers didn't want to listen to ESS loudspeakers. Buyers would come in predisposed to listen to a JBL speaker vs maybe an AR speaker, or a Bose speaker vs an Infinity speaker. If the salepeople suggested listening to a JBL speaker vs an ESS speaker, the potential customer would often change the second contender to one of the other brands. ESS was confident they could sell their product against any other brand but they needed to give the market a reason to even listen to them, and their technology didn't seem to be motivating consumers enough. So at the big meetings with the ad agency about what sort of ad campaign would convince consumers to at least listen to ESS loudspeakers, it was determined that just using repetative ads wouldn't do it. ESS had already had a high frequency of ads. Since consumers said they gave JBL a listen due to their belief that pros used JBL so perhaps JBL made the consumer product they wanted. Consumers also said that as the inventor of the acoustic suspension or direct reflecting or "whatever" loudspeaker, other companies had some credibility with consumers. So the ad agency proposed that ESS go out and do a sextuple blind listening test nationwide with thousands of consumers under tightly controlled conditions, to get documented evidence that ESS loudspeakers sounded better in various price ranges compared to 9 other brands of loudspeakers. This was to be the "credibility hook" ESS supposedly needed to have consumers give them a listen. The Physics, Psychology/psychoacoustics, Audiology and Music departments at 4 major universities in California, Washington state, Wisconsin and Georgia would check the test controls and an outside accounting firm was brought in to tabulate and document the results. Of course ESS wanted to keep as much of the information gained as possible to themselves for future product development. But the gamble was that if their products were sonically superior, they could create an ad campaign that would convince more consumers to give their speakers a listen in retail stores. They gave me the job of actually running the test and managing all the different groups involved. I was chosen because the test was supposed to use the highest quality source material of classical, jazz, rock and pop music and some natural sounds. This meant getting access to original master tapes used to cut master pressing disks. I had the expertise needed to work with the studio people to make the part of the test program material using these tapes, I could manage a touring "road show" and I knew how to use quality test equipment to replicate the test conditions in each location. The musical passages had to be long enough to have some kind of repetative or sustained characeristics that would allow listeners to hear differences in loudspeakers. The program was 40 minutes long and covered every kind of musical material (although there was quite a bit of well recorded vocals in nearly half of the recordings). The speakers were all set up behind acoustically transparent screens that were visually opaque. About half of the listeners were in the near field. Almost every seat in the listening area was in a "sweet" spot. The colleges did allot to promote the participation of their students, staff and anyone who was interested, in newspapers and local radio. There were four different programs and there were four different price levels of speakers, although the programs were rotated between the different price levels. Consumers could come back to take the "test" up to three times if they so desired. Prizes were given out via drawings and the various departments at the universities were allowed to share some of the data collected at their facility. The playback system was never driven to clipping, the level of the balancing pre-amps was set for each speaker based on their average output using pink noise and flat, A, B and C weighted measurements both in the near and far fields. The locations of the speakers on stands was varied and with 9 speakers of which only 6 could be tested at a time even the comparison match-ups were constantly varied. There were tens of thousands of comparisons made by thousands of listeners. Quite a few audio business theories and guesses were tested in these circumstances. The program material did make a difference in the test results. Two different loudspeakers that were compared with different program material might show different audience preferences depending on whether the program material was pop, jazz or classical, so it seemed that even the best loudspeakers were not always "best" for all kinds of music. Of course there were some good loudspeakers that always seemed to do well in head to head comparisons using any program material and others that were just bad and were disliked by most listeners no matter what the program material. Sometimes the room's acoustics influenced the test results so that if the heat in the room built up and the window's opening positions were changed, the test results could change. ESS was able to show in random blind testing that their products were sonically superior "enough" (statistically valid results 5-8x greater than the margin of error) so that the test results were about the equivalent of the in-store research done by the ad agency. An interesting device was the "Comparison Identifier", a large box in the front of the room which displayed a number for "one" speaker in comparison vs the number for the "other" speaker being tested. The box would produce a number between 1 and 9 but the speakers could be labeled with any number at any time even during one listening test session. The test was actually quite well designed so that no speaker had an advantage. A few of the really poor sounding speakers were weeded out after the first hundred or so testing/listening sessions and some cross price-level comparisons could then be made. The marketing campaign (ESS Wins on Campus) was introduced before the tour of test locations was completed and so in Wisconsin during Homecoming week and at Georgia Tech the crowds of listeners wanting to "take the test" were enormous. The information not used for marketing purposes involved how 2 non-ESS branded loudspeakers did compared to each other. But one very startling fact came to light and it forced the testing to stop and the ad campaign to change. The most prefered loudspeaker for all kinds of music was the same at every college. It was the same for any test and any type of program material. Unfortunately this obviously "most preferred" loudspeaker was not the most expensive ESS loudspeaker. It was one of the least expensive ESS loudspeakers. The design criteria for this model of loudspeaker was actually quite elegant and as a model it shows how a device could be purposely made so it might "beat a test". By the time I had watched listeners in thousands of tests I could have designed a loudspeaker that would have always won the test by a statistically significant margin. ESS wasn't happy that their most expensive loudspeaker was only the most preferred by listeners when compared to other company's expensive loudspeakers. It seemed that when people made choices without visual cues as to which speaker "should" be best, their ears guided them in the direction of the most accurate sound, and that wasn't always the most expensive or the biggest loudspeaker. In addition this "up-the-line superiority" wasn't the same for all companies. Whether by design or accident, some companies produced speakers that sounded better as the price increased, but other companies had results like ESS where the tests determined that some of their less expensive loudspeakers were actually their most accurate. It turned out that the corporate philosophy of ESS that was dictated in part by the requirement for all mainline models to use the Heil tweeter, worked against them in some ways. There was also the fact that if the test could be duplicated because it was controlled, then any company could eventually figure out the 4 or 5 keys factors in the listener's sonic decision and design a loudspeaker that would "beat the test". This was an obvious outcome because there really could only be one set of major sonic priorities that people use to decide which loudspeaker sounds more accurate than another. Perhaps the priorities would be slightly different so my 1, 2, 3, 4,and 5 sonic priorities are 2, 5, 1, 6 and 3 for you, but generally there are only so many criteria that determine "realistic sound". Our brains and ears have evolved over a few millions of years making life and death decisions based on what our ancestors heard. So our hearing developed in a certain way prioritizing certain acoustic criteria. What was also obvious was that no one speaker company in 1978 made speaker systems that incorporated the most possible of these criteria in their designs. There were also limitations imposed by the fact that all the tested loudspeakers were bookshelf models because that is what dominated the market at the time. Strangely though, larger floor standing cabinets have many many sonic factors going against them and so it is less expensive to make a more realistic sounding speaker if it is a small or bookshelf model. There is also the "monkey-wrench" factor that dictates that people will be more disposed to spend more money if the loudpseaker they are auditioning looks bigger and more imposing because that loudspeaker seem visually to be worth more money and our visuals are telling our brain that the larger loudspeaker should sound better than smaller loudspeakers. In point of fact, the larger loudspeaker will likely sound less accurate than if the same money was put into a smaller loudspeaker. But the fact that this listening/test research could have been used against its sponsor and the loudspeaker industry as a whole points up how a simple sextuple blind test could become so dangerous for the status quo in loudspeakers in general. This should all give people pause when discussing comparison testing. Is it possible to actually design a test so that the second item being listened to, is not immediately disadvantaged (or advantaged) by it's position in the test? Is there any reason for the manufacturers to support such a test or even to acknowledge the results as being valid for reasons of their own? Is it possible in certain circumstances to even hear sonic differences without resorting to a basic change in venue (like the need to use headphones)? In fact, the loudspeaker and the source material are acknowledged to be the links of the chain that have the most problems, so if there is no effort to actually define how to reduce the magnitude of distortons in these areas, how can any other portion of the system even be tested? As I said in "the emperor's clothes" thread, there have been less than perhaps 10 loudspeaker systems ever made that can realistically reproduce the voice, the piano and natural sounds "accurately". If there has been so little effort to make realistic sounding loudspeakers and program material, what does it matter if the other parts of systems are .1% improved or not? Finally I have another anecdote that actually applies to me and what I want out of a listening test for my audiophile system. In the 80s when the compact disc was getting a firm foothold in audio, AES was concerned enough about what the 18kHz brick wall filter would sound like to try to develop an international listening test to see what kind of sonic impact these filters could have. They developed a test using playback systems that had lots of response output up to 50KHz, the way the Panasonic leaf tweeter could provide and then using playback material recorded with a sampling rate way past 80KHz they tested AES members to see how easily they could detect the insertion of filters of various types at various frequencies while music or real life sounds were being played. The idea was to push a button when you heard a filter inserted and release it when the filter was removed. At 3KHz everything sounded like it was playing over a telephone when the filter was inserted so that was easy. At 10KHz almost everybody noticed filter insertion. At 15 and 18KHz there were still many many engineers who noticed the filters. But at 23KHz I for one have only been able detect a filter about 20% of the time and at 25KHz I didn't hear any differences. But there was one young European recording engineer who kept getting it right all the time well past 20KHz. He was able to focus in on the hiss from the condenser microphone and pre-amp, plus the noise from the mixing console and the dither in the recording while excluding the other sounds in other spectra and he really could hear when these very high frequency filters were inserted and removed. That makes a total of one guy. I am absolutely certain that I would not want that one guy to ever make a decision (for me) in a test about any audio component item because I cannot hear what he hears so I don't want the decision about what is "best" to be made on the basis of any crieria except the ones I can hear. I want a test to determine anything in audio to be so repeatable and available that I can take the test myself because I don't want to base what will be best for me on what someone else can hear or someone else's taste in music. This is one of the things I learned by running a test taken by thousands of people. We all don't hear the same. We all don't make judgements on what sounds best using the same program material. Our sonic priorities for phase/square wave response, frequency response, dynamic reproduction capability, the intrusion of spurious cabinet noises and constant directivity might be similar but what is vastly different is what we DON'T hear. If I can't hear something then it isn't worth me paying for it in a product. I am a fussy listener compared to most and I am a trained audio engineer who can focus on individual specta and instruments while excluding others. But even so I don't want to take someone else's word for what's best even if they are similarly trained , because someone else will either have better or worse hearing than me, and I'll be the one spending the money on the equipment. Also whatever test will be developed to make the decisions about what is best, I want to be able to take it. But in case I didn't mention it, I'd rather not pay for the test itself because I know from experience, just how incredibly expensive this will all be. Paying for credible comparative listening tests is the part I haven't quite worked out yet. By the way, I've spoken to Ed Meitner about sonics many times in the past and I'm sure that he could easily produce the source player, turn-down/turn-up switches (we wouldn't want to make full power switches between products would we?) and level balancing pre-amp circuits needed for the kinds of test people here discuss, but, of course there would be a price to pay and I wouldn't want to be the one paying that price. Watchking Listening isn't a competative sport, but buying equipment is. We don't get enough sand in our glass |
#2
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Comments about Blind Testing
watch king wrote:
The loudspeakers used in home hifi systems do not cool nearly as well as pro loudspeakers, and the negative effects on sonic characteristics due to temperature change are much greater than those demonstrated by professional loudspeakers. And that is just one of the factors involved with loudspeaker compression. These changes in sonic characteristics make it nearly impossible to do any real research on speaker wires that could be relevant to audiophile listening because the test to make such comparison "fair" would be literally impossible to design. By the time listeners could focus on the sound playback of of one of the test wire/products the second product in the test would already be unfairly tested because the test loudspeaker system (acoustic microscope equivalent) will not likely "sound" the same as it did 30 seconds ago. This means that the test passage would need to be made longer and restarted after a specific cooling off time and by then the human acoustic memory is gone. This could be why so many anecdotal testimonials involve hearing "things" after the time was taken to disconnect one set of speaker wires and connect a second set. The speakers probably cooled down and sounded better after the "wire changing period". So quick A/B switching and using short snippets of sound are the most effective for discrimination. I also found pink noise to be very revealing for detecting level and frequency response differences. |
#3
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Comments about Blind Testing
Thank you for a very intersting and thought-provoking post. I completely agree
that "testing" is not so simple as some would have us believe and that experience and 'listening biases' play a large part. One comment below: "watch king" wrote: If there really was a wire that was substantially better sonically then "super consumers" like Disney would do the testing (at whatever cost) so that they could deliver the AES papers that would make greater prestige for Disney. A couple of years ago, MIT was commissioned to completely rewire the recording/performance facility at George Lucas' Skywalker Ranch in No. CA with their cables. Listening isn't a competative sport, but buying equipment is. Right on. Regards, Mike |
#4
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Comments about Blind Testing
I'm not sure this will work because Google groups seems to be an
unreliable post portal for this .rec group but here goes. Are we assuming this is a double blind test with an indicator display and that you are testing something other than loudspeakers? CD players, tuners and interconnect cables are the easiest to test. Phono cartridges and loudspeakers are difficult and headphones are nearly impossible. Power amps and preamps are in the middle difficulty-wise. Whenever possible it is best to give the test listeners a sense of the music when music is the source. So for an easy to test item there would be a reasonable period of musical lead-in and then a countdown as the music came up to test level. Then during the sustained passage (some operatic overtures are good for this and some symphonic passages as well, and of course much of the quartet music produced is great for this, as well as some repetative piano music), the music would be brought to "test" level after which a number of 8-10 second comparisons could easily be made. Usually it is best to have 3 or 4 direct head to head comparisons with one passage because that allows the listener to be absolutely sure they can hear clearly which test item is better than the other. (Of course Unsure should always be a choice, but if Unsure is the most common response then there would likely be no difference between test product X vs test product Y). With test program other than music like pure spoken voice or natural sounds, the listeners need to know what the material really sounds like or the test isn't really valid. This would also be the case with material like single classical guitar (eg. Segovia plays Bach) or single flute, or single "a capella" voice. This is also especially important for any pipe organ music. Musical memory is "helpful" here. Go listen to an organ concert, record it binaurally and then use headphones and when you test the CD player or interconnects, your musical memory will help you judge. Of course speakers shouldn't be tested this way. Speakers should be played both together, loudish to warm up, with the test listeners "not listening" hands over ears will help and then the warm speakers can be compared. Alternatively a different speaker not part of that particular head to head comparison can be played with the musical lead in and then take a 1 second break and start the comparisons at full test level between speaker X and speaker Y. Or alternatively with speakers (only), a "test" can be run at full loudness but the results not counted just to give the listeners the sense of what's coming (more like a countdown 8 switch 7 switch 6 switch etc), then after the first chorus and a return to the main, a real comparison test can be run for useful results (eg. 4-5, 4-5, 5-4, 5-4 END, with 4 and 5 randomly chosen numbers for the two tested speakers for this one portion of the test). Follow that with another comparison and another until the good parts of that song are used up. But for CD players and interconnect cables the testing can be very straightforward. The "moderator" cannot alas partake of the test for the sake of non-biased presentation. All lead-ins, song intros and explanations have to be prerecorded and "played" to the listening testers. Once the test starts it must finish or all results are unusable. There are many many "control restrictions" needed and requiring pre-test documentation of procedures. The musical program material should be rotated throughout the program during different tests to reduce the biases that "program material position" in the test program can create. As often as possible the order which any item is tested first should change. For high power switching of items like amps, speaker cable and speakers make the loudness turndown steps between test items pretty short on the order of .1 seconds from full loudness to 0, then switch, then turn up in .1 seconds. By putting time code onto a CD and having the switches time code driven this can be accomplished. We used telephone touchtone signals to activate the numerical display box. The switch shutdown/turnup can be programmed right onto the CD material although duplicate disks would need to be synchronized somehow if 2 CD players were being compared. The most listening testers can seem to hold their sonic concentration is betwen 20 minutes and 40 minutes. It is an intense experience. On the other hand testers don't seem to be able to fully concentrate until about 2 comparisons into the test or about 1-2 minutes. 20 minutes gives you barely enough time for one throwaway opener and then 6 bits of test material and 40 minutes can allow for 12 or so tests passages but people start getting headaches and listening fatigue. If need be, run the test a number of times with different program material and with intervals of 30-75 minutes between tests. Don't drink too many liquids before a test session. Getting up for the bathroom ends any test with "No valid results". In other words no distractions should be tolerated (no cellphones, no doorbells, no chatting or physical communication between test listeners, sadly-no crying babies and especially no "Just listen to this" kind of cueing.) It's either done professionally or it's useless. This is not to say that perhaps the character of test items A & B will not be immediately noticable after 15 minutes of testing. They may well be different enough to be immediately recognizable, but keep concentration so as to provide results which can be used to determine which item is more accurate or "better". When using one of the very rare "transparent" test listening speakers to test other items, between one and three chairs is about all a Quad ESL 63 or Martin Logan CL-3 can accomodate in the sweet listening spot. Only a very tiny (point souce) loudspeaker can produce the kind of superior quality and wide soundstage with pinpoint imaging needed to make tests with perhaps as many as a dozen possible test seats. Very small loudspeakers with high power handling, very low spurious noise generated by the cabinet, constant directivity, a single driver for the voice band, reasonable bandwidth and phase alignment capability, limit the number of louspeakers that can be used to perhaps 2 or 3 models that have ever been made in the history of audio. Big boxes will not work for this kind of testing because front row seats will hear something dramatically different from middle and back seats. Remove any chairs not full of test listeners. Use preprinted pages with only 2 columns of numbers on them to allow the two test item numbers to be circled or a box to be checked. Don't be surprised if the choice changes with program materials. Listening tests may be exciting but they may not be fun. No matter how people have travelled and might be leaving or how tight their schedules are, if some component used but not being tested develops a buzz or glitch or if the test aparatus malfunctions don't use any of the results. Use the prerecorded "moderator" intros to cue listeners as to what they might listen for, (eg. "the following quartet is composed of flute, cello, violin and trumpet", or "on this recording the piano is the only acoustic instrument and it is mic'd with 2 overstring and one soundboard mix microphone", or "the test comparison will be done during the middle of the 3 minute drum solo") because if there are anomolies to be heard let the testers know when to concentrate the most closely. Watchking listening isn't a competative sport, buying equipment is. We don't get enough sand in our glass. chung wrote in message news:4uVPb.124026$8H.329218@attbi_s03... watch king wrote: The loudspeakers used in home hifi systems do not cool nearly as well as pro loudspeakers, and the negative effects on sonic characteristics due to temperature change are much greater than those demonstrated by professional loudspeakers. And that is just one of the factors involved with loudspeaker compression. These changes in sonic characteristics make it nearly impossible to do any real research on speaker wires that could be relevant to audiophile listening because the test to make such comparison "fair" would be literally impossible to design. By the time listeners could focus on the sound playback of of one of the test wire/products the second product in the test would already be unfairly tested because the test loudspeaker system (acoustic microscope equivalent) will not likely "sound" the same as it did 30 seconds ago. This means that the test passage would need to be made longer and restarted after a specific cooling off time and by then the human acoustic memory is gone. This could be why so many anecdotal testimonials involve hearing "things" after the time was taken to disconnect one set of speaker wires and connect a second set. The speakers probably cooled down and sounded better after the "wire changing period". So quick A/B switching and using short snippets of sound are the most effective for discrimination. I also found pink noise to be very revealing for detecting level and frequency response differences. |
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Comments about Blind Testing
(Watch King) wrote:
snip But for CD players and interconnect cables the testing can be very straightforward. The "moderator" cannot alas partake of the test for the sake of non-biased presentation. All lead-ins, song intros and explanations have to be prerecorded and "played" to the listening testers. Once the test starts it must finish or all results are unusable. There are many many "control restrictions" needed and requiring pre-test documentation of procedures. The musical program material should be rotated throughout the program during different tests to reduce the biases that "program material position" in the test program can create. As often as possible the order which any item is tested first should change. For high power switching of items like amps, speaker cable and speakers make the loudness turndown steps between test items pretty short on the order of .1 seconds from full loudness to 0, then switch, then turn up in .1 seconds. By putting time code onto a CD and having the switches time code driven this can be accomplished. We used telephone touchtone signals to activate the numerical display box. The switch shutdown/turnup can be programmed right onto the CD material although duplicate disks would need to be synchronized somehow if 2 CD players were being compared. The most listening testers can seem to hold their sonic concentration is betwen 20 minutes and 40 minutes. It is an intense experience. On the other hand testers don't seem to be able to fully concentrate until about 2 comparisons into the test or about 1-2 minutes. 20 minutes gives you barely enough time for one throwaway opener and then 6 bits of test material and 40 minutes can allow for 12 or so tests passages but people start getting headaches and listening fatigue. If need be, run the test a number of times with different program material and with intervals of 30-75 minutes between tests. Don't drink too many liquids before a test session. Getting up for the bathroom ends any test with "No valid results". In other words no distractions should be tolerated (no cellphones, no doorbells, no chatting or physical communication between test listeners, sadly-no crying babies and especially no "Just listen to this" kind of cueing.) It's either done professionally or it's useless. Once again you have brought up many important variables that may affect the outcome and validity of any open-ended audio component comparison DBT using music, particularly the amateur DIY variety that are strongly advocated by some posters here. What is your experience in using 'highly experienced listeners" (reviewers, disc masterers, etc.) versus 'average listeners' for blind tests to determine whether there is an audible difference between components? One variable you did not mention is 'control of the switch'. John Atkinson of Stereophile has said he personally has a lot of problems with any blind test where he can't control the switch. What are your thoughts on that issue? Regards, Mike |
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Comments about Blind Testing
Mkuller wrote:
(Watch King) wrote: snip But for CD players and interconnect cables the testing can be very straightforward. The "moderator" cannot alas partake of the test for the sake of non-biased presentation. All lead-ins, song intros and explanations have to be prerecorded and "played" to the listening testers. Once the test starts it must finish or all results are unusable. There are many many "control restrictions" needed and requiring pre-test documentation of procedures. The musical program material should be rotated throughout the program during different tests to reduce the biases that "program material position" in the test program can create. As often as possible the order which any item is tested first should change. For high power switching of items like amps, speaker cable and speakers make the loudness turndown steps between test items pretty short on the order of .1 seconds from full loudness to 0, then switch, then turn up in .1 seconds. By putting time code onto a CD and having the switches time code driven this can be accomplished. We used telephone touchtone signals to activate the numerical display box. The switch shutdown/turnup can be programmed right onto the CD material although duplicate disks would need to be synchronized somehow if 2 CD players were being compared. The most listening testers can seem to hold their sonic concentration is betwen 20 minutes and 40 minutes. It is an intense experience. On the other hand testers don't seem to be able to fully concentrate until about 2 comparisons into the test or about 1-2 minutes. 20 minutes gives you barely enough time for one throwaway opener and then 6 bits of test material and 40 minutes can allow for 12 or so tests passages but people start getting headaches and listening fatigue. If need be, run the test a number of times with different program material and with intervals of 30-75 minutes between tests. Don't drink too many liquids before a test session. Getting up for the bathroom ends any test with "No valid results". In other words no distractions should be tolerated (no cellphones, no doorbells, no chatting or physical communication between test listeners, sadly-no crying babies and especially no "Just listen to this" kind of cueing.) It's either done professionally or it's useless. Once again you have brought up many important variables that may affect the outcome and validity of any open-ended audio component comparison DBT using music, particularly the amateur DIY variety that are strongly advocated by some posters here. Any of the provisos he's cited would *also* apply to sighted comparison, of course...but they certainly don't seem to be applied in the sighted comparisons I read about every month. But then again, nothing he's written even remotely supports the idea that *sighted*, 'open ended' comparison, using music (and please, feel free to add whatever new conditions you can conjure up), advocated and practiced by the most audiophiles, including the two main audiophile magazines, is a good way to test for difference at all. And that's because -- and this is the crucial thing -- it can't *ever* be a good method, for verifying subtle differnces. In other words, in contrast to scientific methods, the method advocated by the main 'voices' of audiophilila, and people like yourself, is *fundamentally and essentially flawed*, as all researchers in the field of perception acknowledge. DBT for audible difference is 'perfectable' -- sighted listening simply *isn't*. -- -S. "They've got God on their side. All we've got is science and reason." -- Dawn Hulsey, Talent Director |
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Comments about Blind Testing
"Mkuller" wrote in message
*snip* quoted text What is your experience in using 'highly experienced listeners" (reviewers, disc masterers, etc.) versus 'average listeners' for blind tests to determine whether there is an audible difference between components? Mike, You have repeatedly brought up the notion that DBTs, particularly of the ABX variety, only have validity in 'trained' listeners and are useless to the untrained. So I ask, if we were to set up a double blind cable discrimination test and prior to running the test, had each testor engage in some ABX training and we subsequently charted their sensitivity to known types of distortions, would you conclude that the ensuing cable test would be valid even if all testors failed to discriminate between the cables? One variable you did not mention is 'control of the switch'. John Atkinson of Stereophile has said he personally has a lot of problems with any blind test where he can't control the switch. What are your thoughts on that issue? Regards, Mike |
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Comments about Blind Testing
And that's because -- and this is the crucial thing -- it
can't *ever* be a good method, for verifying subtle differnces. In other words, in contrast to scientific methods, the method advocated by the main 'voices' of audiophilila, and people like yourself, is *fundamentally and essentially flawed*, as all researchers in the field of perception acknowledge. DBT for audible difference is 'perfectable' -- sighted listening simply *isn't*. Neither one is perfect as it stands now. You happen to prefer your imperfectly applied DBT which obscures differences over my method which doesn't provide "adequate controls" for bias. Otherwise, provide me an example of a 'perfect' DBT with a sensitivity which has been verified to be, say around 0.2db - two times the difference Pinkerton is demanding for his $4.5K Cable Challenge. (Our money is safe.) Regards, Mike |
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Comments about Blind Testing
Any of the provisos he's cited would *also* apply to sighted comparison,
of course...but they certainly don't seem to be applied in the sighted comparisons I read about every month. If you don't like them why are you reading them? But then again, nothing he's written even remotely supports the idea that *sighted*, 'open ended' comparison, using music (and please, feel free to add whatever new conditions you can conjure up), advocated and practiced by the most audiophiles, including the two main audiophile magazines, is a good way to test for difference at all. Equipment reviews are not tests for differences per se. They are subjective reviews of equipment used by the reviewer in the likely manner that the consumer would use the product. And that's because -- and this is the crucial thing -- it can't *ever* be a good method, for verifying subtle differnces. Varification is not an issue in subjective review for the most part. Using the product as the consumer would use it is a reasonable way to evaluate equipment if the consumer who reads the magazine evaluates equipment the same way. If you read the reviews and don't like the fact that they are not scientifically reliable, I suggest you read the disclaimer that suggests consumers shouldn't rely on reviews alone and should audition equipment for themselves before making any purchases. In other words, in contrast to scientific methods, the method advocated by the main 'voices' of audiophilila, and people like yourself, is *fundamentally and essentially flawed*, Yes they are. As is the case for any subjective review. Stereophile is not trying to be a scientific journal. Most journals that do subjective reviews of hardware in any number of fields are every bit as unscientific. DBT for audible difference is 'perfectable' -- sighted listening simply *isn't*. I wouldn't expect such absolute claims from a scientist. |
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Comments about Blind Testing
S888Wheel wrote:
Any of the provisos he's cited would *also* apply to sighted comparison, of course...but they certainly don't seem to be applied in the sighted comparisons I read about every month. If you don't like them why are you reading them? Component reviews are typically a mix of fact -- how many inputs/outputs does the device have, what formats does it play, what materials and parts were used in its construction, how is the remote laid out , how does it differ from previous or competing models in terms of features , etc -- and possibly spurious subjective impression about the sound . Guess which part I find most valuable. But then again, nothing he's written even remotely supports the idea that *sighted*, 'open ended' comparison, using music (and please, feel free to add whatever new conditions you can conjure up), advocated and practiced by the most audiophiles, including the two main audiophile magazines, is a good way to test for difference at all. Equipment reviews are not tests for differences per se. They are subjective reviews of equipment used by the reviewer in the likely manner that the consumer would use the product. Which does not make the conclusions drawn any more tenable...all it means is that both reviewer and consumer tend to evaluate the sound of a component in a manner that is unlikely to be particularly reliable or accurate. But it does make them feel good. And that's because -- and this is the crucial thing -- it can't *ever* be a good method, for verifying subtle differnces. Varification is not an issue in subjective review for the most part. Indeed. But these 'subjective reviews' you talk about do *not* confine themselves purely to statemenst such as, "I liked this one", "I didn't like that one"; "This one made me feel good", or the like. They instead often *do* involve comparisons (often to the reviewer's 'reference system') and they *do* make *specific claims* about one 'throwing a better soundstage' or 'sounding less harsh' or 'clarifying the bass'. Under thy typical review conditions there is a distinct possibility that these impressions are NOT the result of actual sonic differences, but are *entirely* psychological in origin -- a likelihood that science tells us cannot be confidently dismissed without more controlled comparison. Reviewers pretend this isn't the case. Using the product as the consumer would use it is a reasonable way to evaluate equipment if the consumer who reads the magazine evaluates equipment the same way. Yes, the community of belief is a strong component of the hobby. But is the belief warranted by the facts? At what point does the hobby become more 'faith based' than fact-based? If you read the reviews and don't like the fact that they are not scientifically reliable, I suggest you read the disclaimer that suggests consumers shouldn't rely on reviews alone and should audition equipment for themselves before making any purchases. Do these disclaimers -- where are they printed , btw, in the current issues of the usual audio journals? -- further recommend that the personal auditions be carried out in a scientifically reliable manner? Repeating the error of the reviewer yourself isn't going to get you closer to reliable. In other words, in contrast to scientific methods, the method advocated by the main 'voices' of audiophilila, and people like yourself, is *fundamentally and essentially flawed*, Yes they are. As is the case for any subjective review. Stereophile is not trying to be a scientific journal. Most journals that do subjective reviews of hardware in any number of fields are every bit as unscientific. I'll never understand why you think telling me that *lots* of journals have poor standards of objective proof for their claims, is any sort of argument *for* sighted comparison. What sorts of products are you thinking of? DBT for audible difference is 'perfectable' -- sighted listening simply *isn't*. I wouldn't expect such absolute claims from a scientist. All it means is that you can 'refine' a sighted method forever, and the results will always have a huge, intrinsic question mark over them. By contrast DBT can shrink the size of that question mark to the point of *scientific* certainty...which is the strongest kind of certainty we can achieve about the natural world. -- -S. "They've got God on their side. All we've got is science and reason." -- Dawn Hulsey, Talent Director |
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Comments about Blind Testing
Component reviews are typically a mix of fact -- how many
inputs/outputs does the device have, what formats does it play, what materials and parts were used in its construction, how is the remote laid out , how does it differ from previous or competing models in terms of features , etc -- and possibly spurious subjective impression about the sound . Guess which part I find most valuable. Certainly the same part I do. Which does not make the conclusions drawn any more tenable...all it means is that both reviewer and consumer tend to evaluate the sound of a component in a manner that is unlikely to be particularly reliable or accurate. But it does make them feel good. Which is the bottom line in any hobby. Indeed. But these 'subjective reviews' you talk about do *not* confine themselves purely to statemenst such as, "I liked this one", "I didn't like that one"; "This one made me feel good", or the like. They instead often *do* involve comparisons (often to the reviewer's 'reference system') and they *do* make *specific claims* about one 'throwing a better soundstage' or 'sounding less harsh' or 'clarifying the bass'. Under thy typical review conditions there is a distinct possibility that these impressions are NOT the result of actual sonic differences, but are *entirely* psychological in origin -- a likelihood that science tells us cannot be confidently dismissed without more controlled comparison. All true and all a possible reaction that any given consumer may have to such a new piece of equipment. Just because the reviewer is more detailed in describing their impressions of a given piece of equipment doesn't make their impression any less real or any less like the sort of impressions that any consumer may also have. Reviewers pretend this isn't the case. The disclaimer says enough IMO. It is clear that the editor of Stereophile does not hold the subjective opinions of the reviewers as definitive. I haven't seen any reviewer specifically claim that thier subjective impressions are universally infalable. Yes, the community of belief is a strong component of the hobby. But is the belief warranted by the facts? At what point does the hobby become more 'faith based' than fact-based? At the point where people draw their conclusions based on what they are told rather than what they experience. You cannot blame a magazine that tells it's readers to not use subjective reviews as definitive claims of performance and to audition equipment for themselves before purchasing equipment for some audiophiles acting on faith. Do these disclaimers -- where are they printed , btw, in the current issues of the usual audio journals? -- further recommend that the personal auditions be carried out in a scientifically reliable manner? Repeating the error of the reviewer yourself isn't going to get you closer to reliable. They do not suggest how people audition equipment for themslves. Just that they do so. I believe these disclaimers can be found in the introduction to every recomended components list. It is your opinion that a reviewer or a consumer is in error if they do not use scientifically valid methods for testing thier subjective impressions. But then *all* of the advocates of DBTs on RAO clearly chose the one component that they believe matters most in the same unreliable manner. The bottom line how a hobbyist feels about his or her participation in the hobby. I'll never understand why you think telling me that *lots* of journals have poor standards of objective proof for their claims, is any sort of argument *for* sighted comparison. I agree that it is unlikely you will ever understand. I suggest you give careful thought as to why skeptics spend their time on bigfoot UFOs and holistic medicine and not hobbies like audio and photography. What sorts of products are you thinking of? Toys for grownups. All it means is that you can 'refine' a sighted method forever, and the results will always have a huge, intrinsic question mark over them. By contrast DBT can shrink the size of that question mark to the point of *scientific* certainty...which is the strongest kind of certainty we can achieve about the natural world. OK, if this is what you meant by 'perfectable' than I am OK with your claim. I think perfectable per se goes beyond scientific certainty. |
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Comments about Blind Testing
Steven Sullivan wrote:
S888Wheel wrote: Any of the provisos he's cited would *also* apply to sighted comparison, of course...but they certainly don't seem to be applied in the sighted comparisons I read about every month. If you don't like them why are you reading them? Component reviews are typically a mix of fact -- how many inputs/outputs does the device have, what formats does it play, what materials and parts were used in its construction, how is the remote laid out , how does it differ from previous or competing models in terms of features , etc -- and possibly spurious subjective impression about the sound . Guess which part I find most valuable. I also read them for the pure entertainement value. I find amusing how many different ways someone can describe the "sound" of a cable. |
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Comments about Blind Testing
S888Wheel wrote:
Which does not make the conclusions drawn any more tenable...all it means is that both reviewer and consumer tend to evaluate the sound of a component in a manner that is unlikely to be particularly reliable or accurate. But it does make them feel good. Which is the bottom line in any hobby. In butterfly collecting, one wants to know the *actual* facts of the creature's taxonomy, life cycle, geographical distribution, etc....not a collection of comforting communal beliefs. One may *want* to believe that a Luna moth is a rare species, when one has one in a collection -- they are quite pretty, after all -- or that it's life cycle is peculiar, but in fact it's not and it isn't. Lepidopterists accept these facts with no complaint or cavilling about the small-mindedness of entomologists. They don't indulge in special pleading that 'maybe science just doesn't know' or 'science can't measure everything'. In most hobbies, claims of difference are based on incontrovertibly visual evidence. Indeed. But these 'subjective reviews' you talk about do *not* confine themselves purely to statemenst such as, "I liked this one", "I didn't like that one"; "This one made me feel good", or the like. They instead often *do* involve comparisons (often to the reviewer's 'reference system') and they *do* make *specific claims* about one 'throwing a better soundstage' or 'sounding less harsh' or 'clarifying the bass'. Under thy typical review conditions there is a distinct possibility that these impressions are NOT the result of actual sonic differences, but are *entirely* psychological in origin -- a likelihood that science tells us cannot be confidently dismissed without more controlled comparison. All true and all a possible reaction that any given consumer may have to such a new piece of equipment. Just because the reviewer is more detailed in describing their impressions of a given piece of equipment doesn't make their impression any less real or any less like the sort of impressions that any consumer may also have. And it doesn't make these 'impressions' any closer to *true*. In the case where in fact there is *NO DIFFERENCE*, isn't it absurd to talk of the impressions being 'real'? They are only 'real' in the trivial sense that a false statement remains 'really' a statement. Your line of reasoning ends up having to assert that the audiophile hobby isn't particularly concerned with what's true. Reviewers pretend this isn't the case. The disclaimer says enough IMO. It is clear that the editor of Stereophile does not hold the subjective opinions of the reviewers as definitive. I haven't seen any reviewer specifically claim that thier subjective impressions are universally infalable. What disclaimer? Have you seen any reviewer claim that their impressions could in fact be entirely spurious? Have you seen any admit that, absent controls for bias, level matching, etc, the likelihood that impressions about cable or amp or CD 'sound' are *entirely* spurious, cannot be dismissed? Yes, the community of belief is a strong component of the hobby. But is the belief warranted by the facts? At what point does the hobby become more 'faith based' than fact-based? At the point where people draw their conclusions based on what they are told rather than what they experience. You cannot blame a magazine that tells it's readers to not use subjective reviews as definitive claims of performance and to audition equipment for themselves before purchasing equipment for some audiophiles acting on faith. But 'audition for yourselves' is not a sufficiently detailed piece of advice, Scott, as regards *verifying audible difference*, any more than 'trust your ears' is. It's little more than slogan or mantra, unless accompanied by information about factors that can produce false impressions during those auditions. Do these disclaimers -- where are they printed , btw, in the current issues of the usual audio journals? -- further recommend that the personal auditions be carried out in a scientifically reliable manner? Repeating the error of the reviewer yourself isn't going to get you closer to reliable. They do not suggest how people audition equipment for themslves. Just that they do so. Exactly. Which makes these disclaimers no more useful as truth-finding advice about the 'sound' , than the reviews themselves. The same essential flaws in the methodology apply. I believe these disclaimers can be found in the introduction to every recomended components list. It is your opinion that a reviewer or a consumer is in error if they do not use scientifically valid methods for testing thier subjective impressions. But then *all* of the advocates of DBTs on RAO clearly chose the one component that they believe matters most in the same unreliable manner. The bottom line how a hobbyist feels about his or her participation in the hobby. For the hundredth time... People choose components for lots of reasons, not all of which involve the sound: looks, budget, features. Visual differences are easy to verify. Sonic ones often aren't. But journals don't confine themselves only to reviewing the looks and features , do they? DBT advocates differe from others only in their willingnes to *admit* that without DBT, their impression of the 'sound' of cables and amps stands a strong chance of being entirely wrong. Or else they differ in their willingness to actually perform such comparisons. It's also rather schizophrenic of journals to display test measurement results, but then perform their reviews sighted. Why make a nod to some science, but ignore other science? Clearly the journals want to present *some* sort of semblance of technical accuracy. I'll never understand why you think telling me that *lots* of journals have poor standards of objective proof for their claims, is any sort of argument *for* sighted comparison. I agree that it is unlikely you will ever understand. I suggest you give careful thought as to why skeptics spend their time on bigfoot UFOs and holistic medicine and not hobbies like audio and photography. The answer is that far more of the public at large cares about Bigfoot and UFOs and holistic medicine, than about the folklore of audiophiles. And what controversies in photography are analogous to 'cable sound' or 'green pens', Scott? Are there treatments or devices that claim to induce *visible* differences in photographic results, that require a blind comparison for verification? What sorts of products are you thinking of? Toys for grownups. And because they're 'toys', it's acceptable for the hobby to be pervaded by child-like, magical thinking about how those toys work? How odd. Usually children grow out of such beliefs about their toys. -- -S. "They've got God on their side. All we've got is science and reason." -- Dawn Hulsey, Talent Director |
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Comments about Blind Testing
"Mkuller" wrote in message
news:5GgQb.105187$Rc4.724489@attbi_s54... And that's because -- and this is the crucial thing -- it can't *ever* be a good method, for verifying subtle differnces. In other words, in contrast to scientific methods, the method advocated by the main 'voices' of audiophilila, and people like yourself, is *fundamentally and essentially flawed*, as all researchers in the field of perception acknowledge. DBT for audible difference is 'perfectable' -- sighted listening simply *isn't*. Neither one is perfect as it stands now. That's like saying neither Barry Bonds nor Randy Johnson are "perfect" hitters because neither bats 1.000. - Gary Rosen |
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Comments about Blind Testing
Mkuller wrote:
Steven Sullivan wrote: In most hobbies, claims of difference are based on incontrovertibly visual evidence. That's simply not true. One close to High End audio is sports cars. Everyone has their own opinion which they prefer and a lot of it is based on 'the feel of driving it'. I used to own a '95 Acura NSX T-top. Road and Track compared it to the '95 Porsche Targa and '95 Ferrari F-355 convertible. 0-60mph and skid pad specs were almost identical for the three cars. Objectivists might say the three cars had no significant differences. Any subjectivist that drove all three would be able to tell you the differences and which they preferred. I'm not an auto aficionado. Are 0-60 and skid pad spec considered sufficient to determine if two cars are *indistinguishable*? Is 'almost identical' equivalent to *imperceptibly different* in such cases? On what bases are these beliefs founded? If they are based on data that's as strong as those from psychoacoustics, then the rational thing to do would be to test the subjectivists claims in some sort of controlled protocol, where obvious differnces -- such as visual ones -- can have no effect. snip Your line of reasoning ends up having to assert that the audiophile hobby isn't particularly concerned with what's true. *Truth* has many dimensions. If you chose to look at truth through your own filter, you may miss what's true to others... One may believe that the earth is flat, but looking at the world through *that* filter doesn't make the belief any more true. We're not discussing philosophy or aesthetics or religion, Mr. Kuller. We're not talking about the philosophy or semantics of the word 'true' -- or at least, I refuse to go down that pointless road from this point on. Real devices in real systems that induce real sound waves in real air and generate real stimulus from real hair cells in real ears that result in real brain activity that we experience as 'hearing'. That's what we're talking about. It's an unfortunate fact that our judgement about what we hear -- about what *really* was contained in those sound waves -- is demosntrably fallible. Out belief does not necessarily map to what happened. We can even believe two things are different when they are demonstrably the same (e.g., the same component presented twice when we are told it was switched). Our perceptual systems can be fooled. Deny any of that, and you are denying *reality*. -- -S. "They've got God on their side. All we've got is science and reason." -- Dawn Hulsey, Talent Director |
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Comments about Blind Testing
Steven said
Which does not make the conclusions drawn any more tenable...all it means is that both reviewer and consumer tend to evaluate the sound of a component in a manner that is unlikely to be particularly reliable or accurate. But it does make them feel good. I said Which is the bottom line in any hobby. Steven said In butterfly collecting, one wants to know the *actual* facts of the creature's taxonomy, life cycle, geographical distribution, etc....not a collection of comforting communal beliefs. How on earth do you know what all butterfly collectors want? Steven said One may *want* to believe that a Luna moth is a rare species, when one has one in a collection -- they are quite pretty, after all -- or that it's life cycle is peculiar, but in fact it's not and it isn't. Lepidopterists accept these facts with no complaint or cavilling about the small-mindedness of entomologists. They don't indulge in special pleading that 'maybe science just doesn't know' or 'science can't measure everything'. What is your point? Are you saying that audiophiles have unrealistic ideas about the rarity of their music or equipment? I would like to point out however that science does take an interest in the biology of butterflies. It has become quite evident that no such interest exists for audiophilia. Steven said In most hobbies, claims of difference are based on incontrovertibly visual evidence. OSAF. Steven said Indeed. But these 'subjective reviews' you talk about do *not* confine themselves purely to statemenst such as, "I liked this one", "I didn't like that one"; "This one made me feel good", or the like. They instead often *do* involve comparisons (often to the reviewer's 'reference system') and they *do* make *specific claims* about one 'throwing a better soundstage' or 'sounding less harsh' or 'clarifying the bass'. Under thy typical review conditions there is a distinct possibility that these impressions are NOT the result of actual sonic differences, but are *entirely* psychological in origin -- a likelihood that science tells us cannot be confidently dismissed without more controlled comparison. I said All true and all a possible reaction that any given consumer may have to such a new piece of equipment. Just because the reviewer is more detailed in describing their impressions of a given piece of equipment doesn't make their impression any less real or any less like the sort of impressions that any consumer may also have. Steven said And it doesn't make these 'impressions' any closer to *true*. It does for the person having those impressions. Steven said In the case where in fact there is *NO DIFFERENCE*, isn't it absurd to talk of the impressions being 'real'? No. Not if you understand what an impression is. Steven said They are only 'real' in the trivial sense that a false statement remains 'really' a statement. No. They are real in that the person who has a given impression indeed does have that impression. Steven said Your line of reasoning ends up having to assert that the audiophile hobby isn't particularly concerned with what's true. Audiophilia is very much about personal aesthetic experiences for many audiophiles. Why this is so difficult for some to understand seems to be a reflection of those people's limmited scope of understanding aesthetic experiences. Steven said Reviewers pretend this isn't the case. I said The disclaimer says enough IMO. It is clear that the editor of Stereophile does not hold the subjective opinions of the reviewers as definitive. I haven't seen any reviewer specifically claim that thier subjective impressions are universally infalable. Steven said What disclaimer? I already answered this. Steven said Have you seen any reviewer claim that their impressions could in fact be entirely spurious? Not entirely. But it would be pretty absurd to think their impressions are "entirely spurious" IMO. Steven said Have you seen any admit that, absent controls for bias, level matching, etc, the likelihood that impressions about cable or amp or CD 'sound' are *entirely* spurious, cannot be dismissed? I have seen no laundry lists of all the possible caveats that any review may be subject to. I think the general disclaimer suggesting that people listen and decide for themselves covers it. But I already told you this. Steven said Yes, the community of belief is a strong component of the hobby. But is the belief warranted by the facts? At what point does the hobby become more 'faith based' than fact-based? I said At the point where people draw their conclusions based on what they are told rather than what they experience. You cannot blame a magazine that tells it's readers to not use subjective reviews as definitive claims of performance and to audition equipment for themselves before purchasing equipment for some audiophiles acting on faith. Steven said But 'audition for yourselves' is not a sufficiently detailed piece of advice, Scott, as regards *verifying audible difference*, any more than 'trust your ears' is. Why does the advice need to be detailed? Are you suggesting that reviewers are obligated to give detailed instructions on how to audition equipment? Steven said It's little more than slogan or mantra, unless accompanied by information about factors that can produce false impressions during those auditions. I disagree. It is IMO a simple disclaimer that points out the reader may not agree with the reviewer's findings. Steven said Do these disclaimers -- where are they printed , btw, in the current issues of the usual audio journals? -- further recommend that the personal auditions be carried out in a scientifically reliable manner? Repeating the error of the reviewer yourself isn't going to get you closer to reliable. I said They do not suggest how people audition equipment for themslves. Just that they do so. Steven said Exactly. Which makes these disclaimers no more useful as truth-finding advice about the 'sound' , than the reviews themselves. The same essential flaws in the methodology apply. Balony. They let the readers know that the reviews are not to be taken as dogma. That is very useful information for the highly impressionable readers you seem to be so concerned about. I said I believe these disclaimers can be found in the introduction to every recomended components list. It is your opinion that a reviewer or a consumer is in error if they do not use scientifically valid methods for testing thier subjective impressions. But then *all* of the advocates of DBTs on RAO clearly chose the one component that they believe matters most in the same unreliable manner. The bottom line how a hobbyist feels about his or her participation in the hobby. Steven said For the hundredth time... People choose components for lots of reasons, not all of which involve the sound: looks, budget, features. Visual differences are easy to verify. Sonic ones often aren't. But journals don't confine themselves only to reviewing the looks and features , do they? No. If you have a problem with it don't support any of the journals that offer subjective reviews of equipment. That would be all of them by the way. Steven said DBT advocates differe from others only in their willingnes to *admit* that without DBT, their impression of the 'sound' of cables and amps stands a strong chance of being entirely wrong. Or else they differ in their willingness to actually perform such comparisons. This is just plain funny given the fact that those same advocates seem to be quite cetain thier impressions are quite right. Maybe you could cite a DBT advocate who believes thier "impressions" of the sound of any cable or amp "stands a strong chance of being entirely wrong." I will say though, plenty of people I know who don't rely on DBTs are quite aware that their impressions may be in some part wrong and is not entirely reliable. I include myslef in this group. Steven said It's also rather schizophrenic of journals to display test measurement results, but then perform their reviews sighted. Since they all do this and you seem to think it is crazy. Maybe you should start a journal that does all it's subjective listening double blind. Steven said Why make a nod to some science, but ignore other science? Reporting bench tests is no more a nod to science than reading a clock or a thermometer. Steven said Clearly the journals want to present *some* sort of semblance of technical accuracy. Yeah. So? Steven said I'll never understand why you think telling me that *lots* of journals have poor standards of objective proof for their claims, is any sort of argument *for* sighted comparison. I said I agree that it is unlikely you will ever understand. I suggest you give careful thought as to why skeptics spend their time on bigfoot UFOs and holistic medicine and not hobbies like audio and photography. Steven said The answer is that far more of the public at large cares about Bigfoot and UFOs and holistic medicine, than about the folklore of audiophiles. And what controversies in photography are analogous to 'cable sound' or 'green pens', Scott? Lense quality is a hotly debated subjective issue. Steven said Are there treatments or devices that claim to induce *visible* differences in photographic results, that require a blind comparison for verification? Interesting question. It seems the lines drawn in photography never beg for blind verification. I suspect a blind verification would remove the possibility of sighted bias. Steven said What sorts of products are you thinking of? I said Toys for grownups. Steven said And because they're 'toys', it's acceptable for the hobby to be pervaded by child-like, magical thinking about how those toys work? How odd. Usually children grow out of such beliefs about their toys. Usually truly objective people don't burn so many straw men. |
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Comments about Blind Testing
"watch king" wrote in message ...
Maybe comparitive testing of large voltage wire should be done using thin film or electrostatic headphones because these devices are actually better at exposing tiny differences in audio characteristics. Guess how I do my listening tests? |
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Comments about Blind Testing
"Mkuller" wrote in message
... Steven Sullivan wrote: In most hobbies, claims of difference are based on incontrovertibly visual evidence. That's simply not true. One close to High End audio is sports cars. Everyone has their own opinion which they prefer and a lot of it is based on 'the feel of driving it'. I used to own a '95 Acura NSX T-top. Road and Track compared it to the '95 Porsche Targa and '95 Ferrari F-355 convertible. 0-60mph and skid pad specs were almost identical for the three cars. Objectivists might say the three cars had no significant differences. Any subjectivist that drove all three would be able to tell you the differences and which they preferred. No objectivist would say the cars had "no significant differences" based on two narrow measurements. But a subjectivist might say one car "felt" faster when the difference was really the firmness of the seat padding. - Gary Rosen |
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Comments about Blind Testing
On 26 Jan 2004 18:53:04 GMT, (Mkuller) wrote:
Steven Sullivan wrote: In most hobbies, claims of difference are based on incontrovertibly visual evidence. That's simply not true. One close to High End audio is sports cars. Everyone has their own opinion which they prefer and a lot of it is based on 'the feel of driving it'. I used to own a '95 Acura NSX T-top. Road and Track compared it to the '95 Porsche Targa and '95 Ferrari F-355 convertible. 0-60mph and skid pad specs were almost identical for the three cars. Objectivists might say the three cars had no significant differences. Any subjectivist that drove all three would be able to tell you the differences and which they preferred. Actually, objectivists would point to readily measurable differences in spring/damper rates, roll centres, steering rack gearing, engine gearing, and exhaust note tuning, to explain how these cars feel on public roads as opposed to test tracks. High performance cars don't just *happen*, y'know, they are very carefully *engineered* to feel the way they do. How do you think that BMW manage to make both razor-sharp rorty-sounding Z4s and big wallowy 7-Series barges? As with SNR and THD, 0-60 and lateral G are pretty useless measures for high performance products. snip Your line of reasoning ends up having to assert that the audiophile hobby isn't particularly concerned with what's true. *Truth* has many dimensions. If you chose to look at truth through your own filter, you may miss what's true to others... I'm sure you'd like to think that truth is somehow able to mould itself to your personal prejudices, but that isn't the case, the non-existence of 'cable sound' being but one example. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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Comments about Blind Testing
First there seems (from the emails I've received directly) to be some
misunderstanding about my statements concerning blind testing. I think blind testing is the best way to make determinations about whether one audio product is superior in the circumstances where products either measure identically or if their various distortions and specifications differe in ways that would not immediately demonstrate the superiority of one item or items. The only considerations are that the tests be designed to be equal for each item tested, that the listeners would not know except from listening which item is being used at any moment, that the test be repeatable and that the order of the items being tested should change at random moments so that (for example) if the first set of tests has one item going first 1st, 3rd, 6th and 8th, then during the next round with the same program material (and everything else) the test have that same item going 2nd, 4th, 5th and 7th. Now a comment on the idea of the "trained listener" that is being bandied about. What does this mean? In my experience professional recording engineers are trained listeners. They really aren't any better at listening testing than any other listeners and in some circumstances they can have an incredible bias that makes them useless as test listeners. In the circumstance that a recording engineer has played a piece of music he is intimately familiar with, through his own studio monitors, his preferences afterwards if that recording is ever played is worthless. I've been to the former JVC Cutting Studio many times. The place was full of well trained professional recording engineers and they listened to hundreds of different master recordings (both digital and analog) through their own mastering monitors. They would be poor listening test subjects. It would be no different for engineers who listened mostly on UREI Time Aligns(Altec 604s), or any number of other JBL, Tannoy, Fostex, Yamaha, Westlake or other studio monitors. These listeners just have such huge built in listening biases that it would be difficult for them to be objective about the "total quality" of one audio product VS another in a blind listening test unless their loudspeakers and facilites were used. These loudspeakers and facilites might never be able to demonstrate a variety of audio characteristics. I have worked with dozens of other professionally trained listeners and engineers who also had enormous biases about what constitutes natural sound. Even Disney Imagineers may be highly biased, even though their goal is supposed to be designing sound systems (or purchasing premade systems) based on the best sonic quality or most natural sound (along with reliability, sufficient output to do the job, and other non-sonic quality considerations). And all Imagineers are professionally trained listeners. It's true that some Imagineers also reseachr the best of the esoteric audio world but not many. Still I'd say that Disney Imagineers are generally more interested in every and any device that could enhance sonic quality. But Imagineers would not be much better as test listeners than any novice listener that really had a broad interest in music, spoken word, natural sounds or cinema. So does the reference to "trained listeners" imply that there is some other expertise these listeners need to have that would make them better or different from the normal recording engineer's skill at listening to specific spectra or perhaps goes beyond the trained engineer's long years of experiencing the sound of real instruments and voices? If so what is this quality that makes these "trained listeners" better than professional audio engineers? I've never seen it (or heard it). Even when I was selling esoteric audio at retail I never met a "golden ear" who had anything over the trained professional recording engineers I met later in my career. Even the most highly "respected" golden earred listeners of audiophile equipment usually only seemed to have their own specific biases that was supported by their own little group of followers. These "audiophiles" could usually argue well, and were superb at justifying why the faults of the products they labeled superior were less important than the faults of the products they labeled inferior. Generally I met almost no audiophiles whose sonic judgement I would trust more than many trained professional recording engineers. The best of each group could be possibly very focused listeners, very fussy listeners or there are even some I like to label "savant" listeners. Some have big egos and some don't. But there is not one trained listener I've met who would be the "best" listening test subject. Some trained listeners can make faster determinations about why one product sounds better than another compared to most people, but the decisions they make are usually very much parallel to those made by untrained listeners as long as the test is properly designed to be fair and meaningful. I've often discussed audio in the halls of CES with amp designers of products like Krell, B&K, Bryston, Carver, Threshold, Conrad Johnson, Quad and Lazarus and not only have these people been willing to lend their amps to me for use in my displays, I've had many other designers come into my displays to listen and discuss audio. Amp designers listen allot because they want to be sure their products don't have "bad reactions" to all the different loudspeakers on the market. These are electronics engineers with thousands of hours of focused listening. Perhaps they are self-trained but they are often very skilled at hearing tiny differences between products. Again I've noticed that even this group of trained listeners might hear quality differences faster, but they don't hear them any better. So I don't understand this emphasis on trained listeners being some kind of especially capable listener who can hear things other listeners can't. In fact it usually works the other way around . Trained listeners who don't get a constant diet of nearfield experience with live music often tend to be more "in the box" as opposed to being open-minded. Sometimes it is the sad result of ego forcing them to always choose a product whose "sound" is one they recognize or have publicly stated is superior. If not for gigantic egos unwilling to be openminded, there would likely only be 25 or 30 loudspeaker makers instead of hundreds. Also if it were a certainty that any particular listener was better than others, the best financed companies would hire them to compared that company's products to everything else on the market. But this isn't the case no matter how many "golden earred" listeners claim they hear better than anyone else. In fact normal listeners are just as good at determining which audio product sounds better than others (if there are any differences to hear). The 21 year old European novice recording engineer who demonstrated this when he was able to "hear" 98% of the time when a 23khz filter was inserted into the AES program material was more like an untrained listener. No other trained listeners could do it more than 40% of the time. Remember this was a filter-in/filter-out test with button pushed & released to match when the change in sonic character occurred. Even more important to remember was this was a test to determine whether people could hear a "difference" sonically when there was a definite electrical difference. Maybe the engineer "liked" the filtered program better than the unfiltered program, even though the unfiltered material would measure better for phase/squarewave response, noise, and the total amount of distortion in the "audible" program (Thus explaining Quad fans). ANY listener who is careful, focused and has some sonic reference points remembered from hearing live voices and instruments can be a good listening test subject. A good listening test particiapant is something completely different from knowing allot about audio and music in general. This is what seems to confuse most people and it is something people with allot of general audio and music knowledge want to deny because they want to believe they are special golden earred listeners because they know allot about audio or music. A good test listener has to be able to hear differences in sound only if they are there and they have to be able to make judgements about which item sounds better than the other if there really is a difference. It's that simple. Human beings are a group of interactive sensors and measuring instruments, tied into a large central processor that not only makes quality judgements based on direct measurement but also based on each individual's history, temprement and education. Normally if there is a difference in sonic quality it can be measured or quantified. Sometimes measuring product A's 9 non-linearities vs product B's 9 different non-linearities makes it difficult to determine which item's overall sonic quality is superior to the other's. Properly arranged listening tests just narrow the focus of these quality judgements so they can be more easily identified. If the purpose of an audio playback system is to fool the ear/brain combo into believing the listener has been transported to some space where a live performance or sound exists, then there can be tests to see how close or far away that goal is by testing one product in the chain at a time. Let's be careful that we hear real quality differences. Sometimes there can be two distoritons present, one irritating and one masking. If a product removes the masking distorion then perhaps the irritating distorion becomes more audible. This is a real possibility. But usually differences are singular, and other times listening tests point out which of two different distortions is the most irritating. But training beyond an hour or two to warm up test listeners doen't really make a difference in whether anyone can hear sonic quality differences. Healthy ears, focused minds, and a personal liking for the sounds they are hearing usually makes the best listeners for tests. People who always have to be right, those who have been too acoustically imprinted by previous listening of certain program material or those who have a large amount of image and ego invested in the tests' outcomes usually make the worst listeneing subjects. Now for some of my opinons about consumer magazines that have product "tests". The electronic tests may be helpful or fun information especially when features are described. The desire to please potential advertisers make most magazines focus on saying something nice about products sonically. The fact that most magazines will not point out real sonic problems is a diservice to readers. No magazine I've ever read does real blind listening tests to even choose their best and most recommended products. About the best I can say is that if a reader finds after comparing a few dozen product auditions that any reviewer has done, with their own auditions of audio products and then finds themselves always in agreement with that particular reviewer, then reading that reviewer's articles about products could save time. Otherwise I find most magazines are either driven by advertising and thus could care less about consumers, or they are driven by the need to suck up to or be courted by manufacturers to get equipment and favors or special treatment at shows and thus could care less about consumers. A few of these product "reviewers" can be funny or edgy writers, and reading their reviewes can be interesting. This doesn't mean they can hear anything of any special importance that others can't hear but maybe their writing is readable. But beware of the priorities of most reviewers. I visited many magazine editors and test "facilities" in both the audiophile and mid-fi markets. I've often asked about this or that product to get opinions when I saw the product was at the magazine for a review. I was often astounded to find that products which sounded great and were very reliable could be panned while other products that were less reliable or sounded worse would get glowing reviews. When asking for specifics, I was told that the knob on one device wasn't what the reviewer thought was right, or the connector on another device was not up to snuff. This attitude had a disasterous effect in some cases. In the 60s a barrier strip was the normal way speakers were connected to receivers and integrated amps. A spade lug or better yet a circular lug could usually be mounted on a speaker wire and a very solid connection could be made. Magazines later touted the use of push connectors because consumers rated them more convenient. What a terrible move. Push contact connectors had a much smaller conductive surface and barrier strip connectors could have much more secure connections. The switch to push/insert connectors probably hurt the sound quality of systems as much as almost any other change in audio up to the switching power supply fiasco. On the audiophile end, few reviewers for high end publications have much knowledge of room acoutics and acoustic treatments. Some of the listening rooms I saw were abominable. I understand why there seemed to be no relationship between the reviews I read in audiophile magazines and my actual auditions of the same products. This kind of inconsistancy makes it difficult or impossible for companies making really good products to get consistantly good reviews and develop audience confidence (which was why McIntosh originally decided not offer their products for review in most cases when they were ascending the audio heap). So while I am certain from experience that double (or triple or quadruple etc.) blind listening tests can best determine #1) if there are differences between products and #2) whether differences make one product better than another, I don't think these tests should utilize any particular level of trained listener, as long as the listeners are interested, open-minded and careful. Comparing audio to cars or politics seems a bit far afield, but a good comparison might be to compare audio to 3D video imaging. It is still difficult to measure 3D animations to know which animation might look most realistic and current animations fall short of reality in multiple ways. But we still test computers, monitors and storage devices to be used in 3D animation production or viewing. Images are getting better but not all the program material is of the highest quality either visually or thematically. Equipment is also getting better. Eventually it may be possible to make 3D animation which can fool the eye/brain combo the way we try to fool the ear/brain combo with audio. Our eyes' ability to see immediately whether something is animation or real on a 2 D screen is much like determining "reality" with audio program and playback material. Once in a great while we will see a piece of animation that looks authentically "real', and I've had the chance to hear some materials that were able to create "ear/brain fooling" sonic quality. It doesn't happen often and seems to be more rare now in audio than it was in the 70s and 80s, while animation is still moving forward towards "reality". Perhaps this is because in 1973 dollars there is less money being spent on audio now than then. Perhaps audio will become more important again when 3D animation and video get so good that it is always easy to fool the eye/brain combo. We can always hope. Watchking We don't get enough sand in our glass |
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Comments about Blind Testing
"watch king" wrote in message ...
Now a comment on the idea of the "trained listener" that is being bandied about. What does this mean? In my experience professional recording engineers are trained listeners. I'll go with that. Of course, as a professional recording engineer I probably have a vested interest in agreeing with that! Plus, as an undergrad 26 years ago I took two semesters of Listening & Analysis, so perhaps I'm even more of a "trained listener" than most? Hey, I got an A... They really aren't any better at listening testing than any other listeners and in some circumstances they can have an incredible bias that makes them useless as test listeners. In the circumstance that a recording engineer has played a piece of music he is intimately familiar with, through his own studio monitors, his preferences afterwards if that recording is ever played is worthless. [snip] They would be poor listening test subjects. It would be no different for engineers who listened mostly on UREI Time Aligns(Altec 604s), or any number of other JBL, Tannoy, Fostex, Yamaha, Westlake or other studio monitors. These listeners just have such huge built in listening biases that it would be difficult for them to be objective about the "total quality" of one audio product VS another in a blind listening test unless their loudspeakers and facilites were used. These loudspeakers and facilites might never be able to demonstrate a variety of audio characteristics. Sorry, I must disagree with you here. In the first place, our job as professional recording engineers starts with the capturing of a musical event. If we're not intimately familiar with what the actual live performance of that event sounds like...if we haven't gotten our lazy asses out of the control booth and stood out there in the studio or concert hall with the musicians and heard the actual sound coming out of their instruments...then we're not really "professionals". Fortunately, many of us are, and do. Our listening biases are based on an intimate familiarity with live musical performance; *then* and only then do we train ourselves how that sound translates through the monitor speakers of choice. Moreover, it strikes me as pointless to subjectively test audio components for "total quality" in a wide open scenario such as you imply, where one's familarity with some other audio playback system would be considered the benchmark against which any variables would be compared. What sort of information (other than very gross generalizations) would you glean from *any* test which simply asks "Which sounds better?" If you're going to leave the testing that wide open at the very least A) subjects should be required to elaborate on WHY one component sounds "better" (an explanation which, btw, I believe professional recording engineers are usually well qualified to offer), and B) subjects should be comparing to the benchmark of live music. It will take me a while to get through the rest of your entire post, but this early paragraph caught my eye (ear?) & I wanted to respond to it while the notion was fresh. |
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