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Validity of audio tests
I have the following worry about audio listening tests. Suppose the
meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. I am thinking by way of contrast to visual examples. I just made two prints of a photograph using different settings on my printer. I am looking at the face of the subject and I can see that the contrast is higher in one than in the other. That is a Gestalt property of a meaningful chunk of the picture, not a property of a few pixels (cf. notes). The difference with the musical case is that I can compare the contrast of the two pictures directly, whereas in music no immediate comparison is possible. At best I have to keep the property in memory, and maybe the relevant variable is something not easily retained. Is the existing empirical confirmation for tests recommended in audio based largely on visual data? If so, perhaps they rely on factors that apply to the visual domain (i.e., possibility of immediate comparison) but do not transfer easily to audio. Or are there cases in the scientific literature in which the relevant kinds of tests have been found valid to measure the detection of Gestalt properties of aural, temporally extended signals? |
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Mark DeBellis wrote:
I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. Then it's not audible. End of discussion. bob |
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Mark DeBellis wrote:
On 16 Jun 2005 03:14:23 GMT, wrote: Mark DeBellis wrote: I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. Then it's not audible. End of discussion. If you hear something but do not retain a memory of it (sufficient to carry out a certain kind of test), you still heard it. No? In a sense, I suppose, but in that case you can't carry out any kind of a comparison at all. So how could you be conscious of it under any conditions? And if you can't be conscious of it under any conditions, how can you say that you "heard" it? Though I suspect you meant something slightly different, based on another post, so I'll respond to that one. bob |
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Mark DeBellis wrote:
On 16 Jun 2005 03:14:23 GMT, wrote: If you hear something but do not retain a memory of it (sufficient to carry out a certain kind of test), you still heard it. No? I'm pretty sure I've mentioned this book here befo Daniel Dennett's _Conciousness Explained_. Probably my favorite treatese on the physical process of cognition & perception -- thought-provoking, challenging, elucidating and funny to read! Highly recomended. Anyway, I mention this book because, in a nutshell, according to Dennett, the answer to your question is "No." In a slightly bigger nutshell, Dennett goes on to explain (with far more conviction & evidence than I could possibly muster in a newsgroup posting) that there is often a significant & meaningful difference between What We Perceived, and What We Think We Perceived. |
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On 17 Jun 2005 23:48:24 GMT, "Buster Mudd"
wrote: Mark DeBellis wrote: On 16 Jun 2005 03:14:23 GMT, wrote: If you hear something but do not retain a memory of it (sufficient to carry out a certain kind of test), you still heard it. No? I'm pretty sure I've mentioned this book here befo Daniel Dennett's _Conciousness Explained_. Probably my favorite treatese on the physical process of cognition & perception -- thought-provoking, challenging, elucidating and funny to read! Highly recomended. Anyway, I mention this book because, in a nutshell, according to Dennett, the answer to your question is "No." That is an interesting book, and I do remember reading it a while back, and I second your recommendation, but what exactly is the reason to think "No"? There are cases all the time when people perceive things and then forget them. In a slightly bigger nutshell, Dennett goes on to explain (with far more conviction & evidence than I could possibly muster in a newsgroup posting) that there is often a significant & meaningful difference between What We Perceived, and What We Think We Perceived. True, but how does that difference play a role here? |
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Mark DeBellis wrote:
On 17 Jun 2005 23:48:24 GMT, "Buster Mudd" wrote: Mark DeBellis wrote: On 16 Jun 2005 03:14:23 GMT, wrote: If you hear something but do not retain a memory of it (sufficient to carry out a certain kind of test), you still heard it. No? I'm pretty sure I've mentioned this book here befo Daniel Dennett's _Conciousness Explained_. Probably my favorite treatese on the physical process of cognition & perception -- thought-provoking, challenging, elucidating and funny to read! Highly recomended. Anyway, I mention this book because, in a nutshell, according to Dennett, the answer to your question is "No." That is an interesting book, and I do remember reading it a while back, and I second your recommendation, but what exactly is the reason to think "No"? Because "hearing" is a cognitive process; it takes place in the brain, not in the ear. So if your brain tells you you didn't hear it, even if soundwaves did strike your eardrum...and even (!) if at an earlier time your brain told you that you did hear it...for all intents & purposes, you didn't hear it. Saying "I heard it" is only useful if you can access the perception in order to make subsequent discriminations. There are cases all the time when people perceive things and then forget them. At which point any information they may have gleaned from perceiving that thing is lost to them. Hence, the distinction between whether they actually perceived it & then forgot it, or never perceived it in the first place, is moot. In a slightly bigger nutshell, Dennett goes on to explain (with far more conviction & evidence than I could possibly muster in a newsgroup posting) that there is often a significant & meaningful difference between What We Perceived, and What We Think We Perceived. True, but how does that difference play a role here? It goes to the core of your initial question: How valid can an audio test be if it's measuring the perception of phenomena which may not actually exist? |
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"Buster Mudd" wrote:
Because "hearing" is a cognitive process; it takes place in the brain, not in the ear. So if your brain tells you you didn't hear it, even if soundwaves did strike your eardrum...and even (!) if at an earlier time your brain told you that you did hear it...for all intents & purposes, you didn't hear it. Saying "I heard it" is only useful if you can access the perception in order to make subsequent discriminations. I agree with the basic idea that perception is something that influences behavior, but why does the behavior have to be restricted to comparison and identification? Suppose a listener gives higher approval ratings to one set of (blind) stimuli than another, without ever trying to say which stimuli were the same and which were different. This would be an influence on behavior, but of a weaker sort than is required by the "can you reliably identify" type of test. There are cases all the time when people perceive things and then forget them. At which point any information they may have gleaned from perceiving that thing is lost to them. Hence, the distinction between whether they actually perceived it & then forgot it, or never perceived it in the first place, is moot. Not if the information is still doing work somewhere in your cognitive economy, even though it can't be brought to consciousness, or is not specific enough to enable one to perform the identification task. Mark |
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"Mark DeBellis" wrote in message
... "Buster Mudd" wrote: Because "hearing" is a cognitive process; it takes place in the brain, not in the ear. So if your brain tells you you didn't hear it, even if soundwaves did strike your eardrum...and even (!) if at an earlier time your brain told you that you did hear it...for all intents & purposes, you didn't hear it. Saying "I heard it" is only useful if you can access the perception in order to make subsequent discriminations. I agree with the basic idea that perception is something that influences behavior, but why does the behavior have to be restricted to comparison and identification? Suppose a listener gives higher approval ratings to one set of (blind) stimuli than another, without ever trying to say which stimuli were the same and which were different. This would be an influence on behavior, but of a weaker sort than is required by the "can you reliably identify" type of test. Yet if 200 people do the same thing, you can apply statistical measures of difference and determine with high accuracy whether or not subjectively there is a difference, and if so, in what characteristics (assuming the scalar data is pertinent to the differences heard). That is exactly the kind of validation that is missing that would prove (or prove in the negative) whether quick-switch, "short form" tests such as ABX can measure the same thing. There are cases all the time when people perceive things and then forget them. At which point any information they may have gleaned from perceiving that thing is lost to them. Hence, the distinction between whether they actually perceived it & then forgot it, or never perceived it in the first place, is moot. Not if the information is still doing work somewhere in your cognitive economy, even though it can't be brought to consciousness, or is not specific enough to enable one to perform the identification task. Certainly. If you hear it again and respond the same way, it can influence either favorably or unfavorably your reception to the music being played / your evaluation of the system it is being played on. Thus most audiophiles emphasis on long term listening. |
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Mark DeBellis wrote:
"Buster Mudd" wrote: Because "hearing" is a cognitive process; it takes place in the brain, not in the ear. So if your brain tells you you didn't hear it, even if soundwaves did strike your eardrum...and even (!) if at an earlier time your brain told you that you did hear it...for all intents & purposes, you didn't hear it. Saying "I heard it" is only useful if you can access the perception in order to make subsequent discriminations. I agree with the basic idea that perception is something that influences behavior, but why does the behavior have to be restricted to comparison and identification? It doesn't. You can easily do a DBT as, say, a preference test. If the subject reports the same preference at a statistically significant rate, we can assume that the two are different. Suppose a listener gives higher approval ratings to one set of (blind) stimuli than another, without ever trying to say which stimuli were the same and which were different. This would be an influence on behavior, but of a weaker sort than is required by the "can you reliably identify" type of test. There are cases all the time when people perceive things and then forget them. At which point any information they may have gleaned from perceiving that thing is lost to them. Hence, the distinction between whether they actually perceived it & then forgot it, or never perceived it in the first place, is moot. Not if the information is still doing work somewhere in your cognitive economy, even though it can't be brought to consciousness, or is not specific enough to enable one to perform the identification task. But it isn't, because of our short aural memory for partial loudness differences. bob |
#12
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Mark DeBellis wrote:
"Buster Mudd" wrote: Hence, the distinction between whether they actually perceived it & then forgot it, or never perceived it in the first place, is moot. Not if the information is still doing work somewhere in your cognitive economy, even though it can't be brought to consciousness, or is not specific enough to enable one to perform the identification task. How would you go about *proving* that something was in someone's "cognitive economy" if that someone was not conscious of that something? How would you go about *proving* that something was in someone's "cognitive economy" if that something could not enable that someone to perform a task, any task? |
#13
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Mark DeBellis wrote:
I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. Nobody uses short snippets to do audio listening tests or comparisons. We usually use a complete song or passage of an extended work. I am thinking by way of contrast to visual examples. I just made two prints of a photograph using different settings on my printer. I am looking at the face of the subject and I can see that the contrast is higher in one than in the other. That is a Gestalt property of a meaningful chunk of the picture, not a property of a few pixels (cf. notes). The difference with the musical case is that I can compare the contrast of the two pictures directly, whereas in music no immediate comparison is possible. At best I have to keep the property in memory, and maybe the relevant variable is something not easily retained. Not true. You can perform rapid switching as often and as many as you want. You level match the two sources so that the only difference you hear is the sound quality differences between the two. Rapid switching is the audio equivalent of a direct comparison. Your complaint would apply only to long term comparisons, where you listen first to a complete song on one source, then switch to the other source and listen all over again. Gary Eickmeier |
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Gary Eickmeier wrote:
Mark DeBellis wrote: I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. Nobody uses short snippets to do audio listening tests or comparisons. We usually use a complete song or passage of an extended work. I am thinking by way of contrast to visual examples. I just made two prints of a photograph using different settings on my printer. I am looking at the face of the subject and I can see that the contrast is higher in one than in the other. That is a Gestalt property of a meaningful chunk of the picture, not a property of a few pixels (cf. notes). The difference with the musical case is that I can compare the contrast of the two pictures directly, whereas in music no immediate comparison is possible. At best I have to keep the property in memory, and maybe the relevant variable is something not easily retained. Not true. You can perform rapid switching as often and as many as you want. You level match the two sources so that the only difference you hear is the sound quality differences between the two. Rapid switching is the audio equivalent of a direct comparison. Your complaint would apply only to long term comparisons, where you listen first to a complete song on one source, then switch to the other source and listen all over again. Gary Eickmeier I second Garys comment. Some additions: There are ABX switchboxes available, I made one myself with relays to switch between two speaker cables simultaneously on both ends. You can switch any time as much as you like. The music or test signal (I use mostly pink noise) is completely at your disposition, use what you feel gives the best results. The faster and cleaner the switching action, the more subtle differences can be discovered. If you are not into electronics it is better to get a ready made box, to avoid any difference between the channels, like the sound of the relais being different making/breaking or so. -- ciao Ban Bordighera, Italy |
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On 16 Jun 2005 23:53:16 GMT, "Ban" wrote:
Gary Eickmeier wrote: Mark DeBellis wrote: I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. I second Garys comment. Some additions: There are ABX switchboxes available, I made one myself with relays to switch between two speaker cables simultaneously on both ends. You can switch any time as much as you like. Sorry I guess I didn't explain my idea very well. Suppose that in order to perceive the relevant property a listener has to hear an uninterrupted stretch of music from the same source. That is, suppose the relevant property is not a property that belongs to any short snippet of the signal but is rather a property that belongs only to a whole, longer passage, say 5 mins. in length or a whole movement. What I am thinking of here is the SACD vs. CD issue discussed on another thread. I am wondering if the unit over which perception can differ meaningfully can be an extended passage not a brief interval; if so, my switching back and forth between SACD and CD would not be a relevant test, because I would hear neither SACD nor CD as an unbroken extended passage. I guess I am asking basically whether the existing protocols for audio tests make room for the possibility that there can be auditory perception of properties of longer, extended passages, and are sufficient to measure such perception. Perhaps the answer would be that there could not be a difference in perceptible properties of longer passages without a detectable difference in frequency response, which could be heard in quick-switch tests; but is that obvious? Mark |
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Mark DeBellis wrote:
Sorry I guess I didn't explain my idea very well. Suppose that in order to perceive the relevant property a listener has to hear an uninterrupted stretch of music from the same source. That is, suppose the relevant property is not a property that belongs to any short snippet of the signal but is rather a property that belongs only to a whole, longer passage, say 5 mins. in length or a whole movement. What I am thinking of here is the SACD vs. CD issue discussed on another thread. I am wondering if the unit over which perception can differ meaningfully can be an extended passage not a brief interval; if so, my switching back and forth between SACD and CD would not be a relevant test, because I would hear neither SACD nor CD as an unbroken extended passage. I guess I am asking basically whether the existing protocols for audio tests make room for the possibility that there can be auditory perception of properties of longer, extended passages, and are sufficient to measure such perception. Yes. There's nothing that would make a DBT involving full 5-minute samples invalid. However, there's also no reason to think they would work better, as I noted yesterday. (To be completely accurate, the protocols DO require that the subject have the ability to switch any time he wants. But there is nothing that requires him to switch more often than once every 5 minutes if he so chooses.) Perhaps the answer would be that there could not be a difference in perceptible properties of longer passages without a detectable difference in frequency response, which could be heard in quick-switch tests; but is that obvious? Yep. And you're more likely to notice it if you switch quickly and frequently between choices. bob |
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#18
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"Mark DeBellis" wrote in message
... On 16 Jun 2005 23:53:16 GMT, "Ban" wrote: Gary Eickmeier wrote: Mark DeBellis wrote: I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. I second Garys comment. Some additions: There are ABX switchboxes available, I made one myself with relays to switch between two speaker cables simultaneously on both ends. You can switch any time as much as you like. Sorry I guess I didn't explain my idea very well. Suppose that in order to perceive the relevant property a listener has to hear an uninterrupted stretch of music from the same source. That is, suppose the relevant property is not a property that belongs to any short snippet of the signal but is rather a property that belongs only to a whole, longer passage, say 5 mins. in length or a whole movement. What I am thinking of here is the SACD vs. CD issue discussed on another thread. I am wondering if the unit over which perception can differ meaningfully can be an extended passage not a brief interval; if so, my switching back and forth between SACD and CD would not be a relevant test, because I would hear neither SACD nor CD as an unbroken extended passage. I guess I am asking basically whether the existing protocols for audio tests make room for the possibility that there can be auditory perception of properties of longer, extended passages, and are sufficient to measure such perception. Perhaps the answer would be that there could not be a difference in perceptible properties of longer passages without a detectable difference in frequency response, which could be heard in quick-switch tests; but is that obvious? There is a very simple, very powerful way to determine this. But it is not practical or possible for one individual. It is called monadic testing. It requires listening to the segment of music, and rating that musical reproduction *immediately afterwards* using a series of rating criteria. Such criteria might include, for example, a five point scale ranging from: "bass sounded extrememly punchy" to "bass sounded flabby and undynamic". When hundreds of people do this, statistics can be applied to determine if there are in fact perceivable differences, and if so, on what criteria. If I were Harmon Industries, I might design and sponsor such a test on occasion. Frankly, Sony blew an opportunity to do such a test (it would be expensive) for their SACD launch. Imagine if the introductory campaign had included "proof" that SACD sounded better. We'd now have a viable second format. If I were the AES, I might sponsor such a test as a "control test" for single-person tests such as the much bally-hooed ABX test, to advance the state of the art.. But for a given individual it is not a practical test. |
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On 16 Jun 2005 03:14:56 GMT, Gary Eickmeier
wrote: Mark DeBellis wrote: I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. Nobody uses short snippets to do audio listening tests or comparisons. We usually use a complete song or passage of an extended work. I am thinking by way of contrast to visual examples. I just made two prints of a photograph using different settings on my printer. I am looking at the face of the subject and I can see that the contrast is higher in one than in the other. That is a Gestalt property of a meaningful chunk of the picture, not a property of a few pixels (cf. notes). The difference with the musical case is that I can compare the contrast of the two pictures directly, whereas in music no immediate comparison is possible. At best I have to keep the property in memory, and maybe the relevant variable is something not easily retained. Not true. You can perform rapid switching as often and as many as you want. OK but I am saying, suppose the meaningful variable is a property of an extended passage. So you have to listen to an uninterrupted passage in order to perceive the property. Switching back and forth will defeat the purpose, yes? Mark |
#20
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Mark DeBellis wrote:
OK but I am saying, suppose the meaningful variable is a property of an extended passage. So you have to listen to an uninterrupted passage in order to perceive the property. Switching back and forth will defeat the purpose, yes? Yeah, but. First, the problem, if it were a problem, could easily be solved by listening to longer passages. No one's ever heard differences between competent amps/cables doing it that way, either. Second, the research demonstrates pretty clearly that our memory for subtle sonic differences is very limited. In other words, contrary to your conjecture, switching back and forth quickly and frequently really is more effective. bob |
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#22
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Mark DeBellis wrote:
It would not solve the problem because once you had listened to the first passage you would have to remember the property for the duration of the second passage, and I am hypothesizing that you don't have reliable memory for that. That is the problem. OK, so let me get this straight: You listen to one component, hear certain properties, then listen to another component, and hear certain other properties, but by the time it's all over with you can't remember which was which? This pretty much dooms any listening test, doesn't it? Not sure I see the point of your question. Gary Eickmeier |
#23
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Mark DeBellis wrote:
On 17 Jun 2005 03:11:07 GMT, wrote: Mark DeBellis wrote: OK but I am saying, suppose the meaningful variable is a property of an extended passage. So you have to listen to an uninterrupted passage in order to perceive the property. Switching back and forth will defeat the purpose, yes? Yeah, but. First, the problem, if it were a problem, could easily be solved by listening to longer passages. No one's ever heard differences between competent amps/cables doing it that way, either. It would not solve the problem because once you had listened to the first passage you would have to remember the property for the duration of the second passage, and I am hypothesizing that you don't have reliable memory for that. That is the problem. Then how do you know it's a meaningful variable? FWIW, here I am thinking of SACD vs. CD rather than amps or cables. I don't know if it makes a difference, but the intuition is about music not white noise (say). Second, the research demonstrates pretty clearly that our memory for subtle sonic differences is very limited. In other words, contrary to your conjecture, switching back and forth quickly and frequently really is more effective. Is the research that demonstrates this based entirely on the tests that I am saying would not be sensitive to such possibilities? Isn't that a circular argument? If not, what is the relevant research? It's based on tests of human hearing. Your ability to remember partial loudness differences lasts a couple of seconds, tops. You are speculating that there exists something that violates this established fact. What is it, and how do you know? bob |
#24
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Mark DeBellis wrote:
OK but I am saying, suppose the meaningful variable is a property of an extended passage. So you have to listen to an uninterrupted passage in order to perceive the property. Switching back and forth will defeat the purpose, yes? I would say this is a false premise. But perhaps you could give an example of a meaningful variable that is a property of a longer passage. Gary Eickmeier |
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A couple of further ideas to toss out, from an onlooker's perspective
of course. Quick-switch tests are said to be the most sensitive, therefore best, yes? Because they permit finer discriminations. An observation: the ultimate purpose of an audio test is not discrimination per se. That is, it's not as if the job that has to be performed here is to discriminate two sources if they can be, to do the best job of discrimination we can, as if that were the real goal. The real purpose of the test is rather to find out what information is available to the listener in the context of use, or perhaps to estimate an upper bound on that information. It is possible that two sources in the ordinary context of use do not present different information to the listener, even if there are ways to set up testing situations (e.g., at higher volume) where a person could discriminate the sources. All well and good if we do, but it's not like having a test that permits such discrimination is a valuable achievement in itself; what we are basically interested in is making sure that if there are differences of information presented in the ordinary context of use, then they will show up and get discriminated in the test. Question: for all the resolving power quick-switch tests have, for all the power they have to put the stimulus under a microscope and discern small differences of detail, are there certain sorts of properties they are *not* so good at picking up? Is there perhaps a forest-for-trees phenomenon lurking somewhere out there? Here's an off the cuff example. Suppose I have two digital photographs that are identical except that one is 1.01 the size of the other. First I compare them (this is the analogue of the quick-switch test) by comparing small portions of one with the other. The comparison is set up in such a way that when I compare a square portion of one with a square portion of the other, one of them is 1.01 as large as the other. However, I cannot see the difference because these are small areas and the difference in size is below my threshold of discrimination. However, when I compare the wholes I can see the difference in size, because the difference is now greater than the threshold, since the whole is much larger than any of those parts. An auditory example would be tempo. Suppose I am listening to two sources, where the only difference is that one of them has a speed of 1.01 times the other. If I listen to short excerpts any difference is below the just-noticeable-difference, but if the whole example is the Ring cycle, I will notice that one finishes before dark and the other doesn't, I get hungry during one but not the other, etc. So even if quick-switch tests, on balance, are the most sensitive, that doesn't mean there can't be things out there that don't get caught in their net (though they may be detectable in other ways). To come back to the SACD/CD example, my concern is whether, even if the quick-switch test were a "null," there could be differences that the test does not do a good job of proving the existence of. Rather than feel assured that science tells us there could not be such differences, it seems to me pretty apparent that every test has its limitations. Sound plausible? Mark |
#26
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Mark DeBellis wrote:
A couple of further ideas to toss out, from an onlooker's perspective of course. Quick-switch tests are said to be the most sensitive, therefore best, yes? Because they permit finer discriminations. An observation: the ultimate purpose of an audio test is not discrimination per se. No, but if you can't discriminate between two things, then the differences between them are irrelevant. That is, it's not as if the job that has to be performed here is to discriminate two sources if they can be, to do the best job of discrimination we can, as if that were the real goal. The real purpose of the test is rather to find out what information is available to the listener in the context of use, or perhaps to estimate an upper bound on that information. Well, we know that. That's what the science of psychoacoustics is all about. Check it out sometime. It is possible that two sources in the ordinary context of use do not present different information to the listener, even if there are ways to set up testing situations (e.g., at higher volume) where a person could discriminate the sources. All well and good if we do, but it's not like having a test that permits such discrimination is a valuable achievement in itself; what we are basically interested in is making sure that if there are differences of information presented in the ordinary context of use, then they will show up and get discriminated in the test. Question: for all the resolving power quick-switch tests have, for all the power they have to put the stimulus under a microscope and discern small differences of detail, are there certain sorts of properties they are *not* so good at picking up? Is there perhaps a forest-for-trees phenomenon lurking somewhere out there? No there is not, according to all experts in the field. Or do you think you know more than the experts? Here's an off the cuff example. Suppose I have two digital photographs that are identical except that one is 1.01 the size of the other. First I compare them (this is the analogue of the quick-switch test) by comparing small portions of one with the other. The comparison is set up in such a way that when I compare a square portion of one with a square portion of the other, one of them is 1.01 as large as the other. However, I cannot see the difference because these are small areas and the difference in size is below my threshold of discrimination. However, when I compare the wholes I can see the difference in size, because the difference is now greater than the threshold, since the whole is much larger than any of those parts. Irrelevant and off-point visual analogy. Visual analogies don't work. Ever. An auditory example would be tempo. Suppose I am listening to two sources, where the only difference is that one of them has a speed of 1.01 times the other. If I listen to short excerpts any difference is below the just-noticeable-difference, but if the whole example is the Ring cycle, I will notice that one finishes before dark and the other doesn't, I get hungry during one but not the other, etc. But you're not discriminating between the two by listening to them. You're discriminating between them by looking at the clock. (And I don't know what the threshold is for speed variation, but at some point you really would be able to distinguish between them in a standard DBT.) So even if quick-switch tests, on balance, are the most sensitive, that doesn't mean there can't be things out there that don't get caught in their net (though they may be detectable in other ways). So far you haven't come up with a single one. That's because there aren't any. To come back to the SACD/CD example, my concern is whether, even if the quick-switch test were a "null," there could be differences that the test does not do a good job of proving the existence of. Rather than feel assured that science tells us there could not be such differences, it seems to me pretty apparent that every test has its limitations. Sound plausible? No. It sounds like you're grasping at straws because you don't like what the science is telling you. If you live in Kansas, I suggest you run for the state board of ed. bob |
#27
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Mark DeBellis wrote:
An auditory example would be tempo. Suppose I am listening to two sources, where the only difference is that one of them has a speed of 1.01 times the other. If I listen to short excerpts any difference is below the just-noticeable-difference, but if the whole example is the Ring cycle, I will notice that one finishes before dark and the other doesn't, I get hungry during one but not the other, etc. So even if quick-switch tests, on balance, are the most sensitive, that doesn't mean there can't be things out there that don't get caught in their net (though they may be detectable in other ways). To come back to the SACD/CD example, my concern is whether, even if the quick-switch test were a "null," there could be differences that the test does not do a good job of proving the existence of. Rather than feel assured that science tells us there could not be such differences, it seems to me pretty apparent that every test has its limitations. Sound plausible? You can't do a "quick switch" test with two sources that run at different speeds because you can't synchronize them, which would be a dead giveaway in itself, so that is a bad example. If you want to use that example, you will have to listen first to one, then the other, in its entirety, then decide if the speed difference is audible. If so, then do a blind series, listening to a known version, then to a randomly chosen one, and decide whether it is the same or different. In this manner you will eventually arrive at a number for a speed differential that is at the audible threshold. That is the basic idea of how audio research is done. You may find that speed differences of 1.01 will be inaudible to most, but audible to some with perfect pitch. If this is interesting enough a question for you, then do the research and report it. Gary Eickmeier |
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Gary Eickmeier wrote:
Mark DeBellis wrote: OK but I am saying, suppose the meaningful variable is a property of an extended passage. So you have to listen to an uninterrupted passage in order to perceive the property. Switching back and forth will defeat the purpose, yes? I would say this is a false premise. But perhaps you could give an example of a meaningful variable that is a property of a longer passage. I missed your post until now because, for some reason, it didn't download (I'm using Free Agent) from my news server. An example of a property that belongs to a temporally extended passage without belonging to short slices of it is being a descending C major scale, one octave long. That is a property a listener can perceive the passage as having, but it is a property is one that belongs to the whole, not short parts. Another perceivable property that belongs to a temporal whole is the property, belonging to a spoken sentence, of being syntactically well formed. Mark |
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Sorry, one of my previous posts had a couple of extraneous words in
one place; here is a corrected version. Gary Eickmeier wrote: Mark DeBellis wrote: OK but I am saying, suppose the meaningful variable is a property of an extended passage. So you have to listen to an uninterrupted passage in order to perceive the property. Switching back and forth will defeat the purpose, yes? I would say this is a false premise. But perhaps you could give an example of a meaningful variable that is a property of a longer passage. I missed your post until now because, for some reason, it didn't download (I'm using Free Agent) from my news server. An example of a property that belongs to a temporally extended passage without belonging to short slices of it is being a descending C major scale, one octave long. That is a property a listener can perceive the passage as having, but it is a property that belongs to the whole, not short parts. Another perceivable property that belongs to a temporal whole is the property, belonging to a spoken sentence, of being syntactically well formed. Mark |
#30
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Mark DeBellis wrote:
I have the following worry about audio listening tests. Suppose the meaningful variable is a property of an extended passage, not a short snippet. Then a subject's failure to accurately distinguish or re-identify may be due to an inability to retain the property in memory. You have a very good point. It's a shame that so many people here responded only to try to show how you are wrong. Some very important musical percepts correspond to diffuse patterns in the music; form, for example. These patterns work on most listeners; but generally it is only the more experienced listeners who have become *conscious* of how these patterns work. Actually even in local patterns--the local beat, or timbre--it takes time and the proper context to stimulate the corresponding musical precepts. And listening tests that compare only "short snippets," as you say, don't provide that time and context. A test subject will certainly have difficulty remembering these percepts. Consider that animals and humans need to have a good memory for objects in the world that correspond to direct sensation. The more abstract the percept becomes, the less need evolution had to equip creatures with memory for it. There's some need to remember internal states like emotions; less need to remember something more abstract like the degree and quality of the emotion. Another difficulty comes in the subject's attempt to conceptualize and then externalize the percept. To conceptualize: to label the experience. And to externalize: to convey that label to the experimenter. Zen meditators know, for example, that conceptualizing an experience collapses it into a limited number of states. In the test subject, lack of consciousness of the diffuse percepts works against being able to identify them with confidence; the demand of the experiment that the experience be conceptualized provides further difficultues; and the clumsiness of the experimentor with regard to how the test "paradigm" influences the result, all work against the validity of the result. Helen |
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