This thread is a continuation of off-topic posts that started with post #96 on this page: http://forums.slimdevices.com/showthread.php?t=53345&page=10
It's about the research done in Japan that was published in 2000 of which you can find a copy here: http://jn.physiology.org/cgi/content/full/83/6/3548 Better PDF copies that include more tables with data can be found on the web. So, here we pick it up: opaqueice;352224 Wrote: > You regard an internet search for copyright-constrained ABX samples as > evidence that "most" ABX testing uses short samples, and from there > conclude that the ABX protocol is invalid? Don't be silly. Okay, I'll drop that because I seem incapable of explaining the difference between the ABX protocol (okay) and the wide-spread implementation (not okay) of it. It's not the core-issue here. > Of -course- it's not! Those are two tests out of thousands - and you're > trying to conclude something about MOST abx tests? The first of these two studies (Muraoka et al. 1978) is more important in our current context than all the others because the current Redbook specification is a result of it. Also, this study used the CCIR recommendation of 15-20 second samples and 0.5 second interval between samples. Also, the test subjects did a subjective listening test and noted their findings in a questionnaire; all input for the conclusions was taken from these questionnaires and the subjects did not have their brains scanned. When I say that it was flawed, it's because it turned out that by using that procedure, it is not possible to find any evidence for perception of > 20 kHz harmonics by human listeners. They checked that by repeating it with the same music-samples and sound-equipment ("presentation system")used for their new method and the results were in agreement with these of Muraoka et al. (1978). > PART of their results agree (the part that show that the HFS alone are > inaudible), and PART disagree. No, that "disagreed part" you mention was never tested before. The subjects still can't hear the HFS part even when it's played together with the LFS part... but --their brains react to it--. The scope of previous tests never included that possibility and thus did not monitor the brains of the subjects. When working from two different scopes like that, you can't say that there is disagreement as the first test didn't include this part. You can say that the first test missed it. > I'll try one more time. Everyone seems to agree that HFS alone are > inaudible based on PET brain scans etc. Ack. > But these guys find that HFS+LFS is different from just LFS. So there > is something very bizarre and non-linear going on if they are right. Nack. Why is this bizarre? The HFS component is what is in the original sound as from the instruments: high freq. harmonics. When you move the 20 kHz line down to lets say 12 kHz and take a recording of an acoustic instrument without it's harmonics above the 12 kHz "everyone" hears the difference between HFS+LFS vs just LFS. When you play just the HFS, it might even be totally un-recognizable as the instrument. In other words: high harmonics add to the fundamental+low harmonics but are utterly senseless on their own. That's why a very expensive violin sounds better than a plastic toy. The next step up is to make the LFS < 20 kHz and the HFS > 20 kHz and the interesting thing is that humans can't hear the HFS anymore... but their brains register the presence of it anyway! If you call that bizarre it is because you can't let go of the notion that only your ears feed your brain with information when listening to music. Other research like mentioned in other threads has already showed that this is not the case, like even memories of hearing this song or smell or seeing how someone else reacts to the music are all factors for what happens in your brain while listening and thus change the listening experience. These are established facts. Also, very low freq's you will have a hard time of hearing them but you feel them and that changes your listening experience too. So, somehow, no-one knows yet exactly how, very high harmonics are sensed by humans as demonstrated in this study. If you can only accept that after they prove exactly --how-- that is done, that's fine with me, but we all sense it while you're waiting for that proof. (I know, I do it again but I just can't help myself, sorry ;-) > My point was that we have no way of knowing whether that bizarre > non-linear thing is in their equipment or in people's heads. That is a question that must be answered for all research done. The established method is by using multiple and totally different methods of measuring. The primary method they used here was the EEG scan, in the alpha range. These are electrodes that measure brain-patterns in the couple Hz range, like 6 Hz or so. But you are right, the EEG scanner or electrodes could have interference by the high frequency sounds in the room. It is very unlikely because the sensors can't pickup those freq's and while measuring with just the HFS, it didn't show anything. They could even make a measurement without placing the electrodes on the subjects head to prove accurate EEG recordings... but they did something better: a second and totally different measurement of blood-flow in their brains using a PET scanner. This equipment detects radio-active radiation from the brain after injecting the subject with a radio-active solution. There is no way that playing music can interfere with this as there is no radio-activity present in the sound-waves, let alone that it is interfered in exactly the same way as it could do with the EEG method. Both methods alone are very unlikely to have interference from playing music but when both measurements show the strong correlation that they did in this case, you eliminate the chance of flawed measurements completely. This is standard and accepted practice. > To summarize: we know that neither brains nor gear respond to HFS > alone, but that brains+gear respond to HFS+LFS differently than to LFS > alone. But we don't - and can't - know whether that difference is due > to brains or due to gear. The fact that gear doesn't respond to HFS > alone is irrelevant, because neither do brains! Would you be happy when they add a third method, like MRI scan? When do you start believing measuring instruments? The scientific community believes measurements when they can be duplicated using a completely different method of measuring and that is good enough for me and most people. It is why they use EEG in hospitals and work with it's results. They only add a PET or MRI scan when they think the results are outside their expectations but use just 1 method otherwise. Also, note that the study was done by many medical professionals, not just a bunch of audio technicians. They know how to use EEG and PET equipment and have done it many times before on patients etc. cheers, Nick. -- DeVerm ------------------------------------------------------------------------ DeVerm's Profile: http://forums.slimdevices.com/member.php?userid=18104 View this thread: http://forums.slimdevices.com/showthread.php?t=54077 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
