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At 12:10 PM -0800 3/9/98, Laurie Hatch wrote: >Kim illumined: >>Just so's you know.....As I understand the physiological issue, it's >not >volume or high frequencies that cause the discomfort in women. >It's >particular >types of non-harmonic distortion in the audio system, >which will tend to >be >worse at higher volume. I've seen several >discussions of this in audio >engineering journals, usually under the >context of how to get a wider >customer >base for audio products. > >Hmmm. This is really interesting. What are these types of n-h distortion >called? (So I can find out more about this.) Well, now you done it. I was lookin' all smart and then you had to go and ask questions. since I'm not any expert by any means, I'll just point you to some places where you can become one. If you want to learn more, I would suggest popping over to your local university library and taking look at back issues of the Audio Engineering Society Journal, Journal of the Acoustical Society of America, and anything on psychoacoustics. I've got a pretty good book called "Thinking in Sound - the Cognitive Psychology of Human Audition" edited by Stephen McAdams and Emmanuel Bigand, Oxford Science Pulications. Also, "The Science of Musical Sound" by John R. Pierce, W.H. Freeman and Company. I'm not sure if either directly answers this question, but you will learn a lot about how you hear and how amazing your ears and brain are. Both of those come from David Wessel's course on psychoacoustics at UC Berkeley, taught in the lovely CNMAT facility. (I missed that class but bought the books.) You might want to sit in on some lectures and ask him directly, he'd probably know. Audio Amateur magazine often has interesting, if poorly researched, articles on the subject audio effects on hearing. Typically related to hobbyist amplifier design and how it can be made that much more subtly better by some strange circuit. Nice mag though. > Also, a question comes to mind >regarding human sensitivity in detecting distortion. Assuming we're >talking >about musicians or people with well-trained, discriminating hearing: is >there >inharmonic distortion occurring below the range of conscious perception >that >affects us negatively before we actually are aware of hearing it? yes. as with all human senses, there are many things you don't consciously notice but you are still sensing them. Like the fact that your nose is in your field of vision but you mostly don't see it. In my case, that is truly amazing. > Might I >start feeling uncomfortable before I am able to consciously identify this >type >of distortion, even if I was somehow miraculously blessed with a superbly >sophisticated ear? as I understand things, yes. I imagine if you really knew what you were listening for you might be able to hear it. Not sure though. >(My question comes in part from reading about phase >distortion in amplifiers or equalizers. My text source tells me the >associated >slight reduction of response is generally not noticeable. Does it, >however, >have any measurable effect on the listener, even when not audibly >perceived?) phase distortion is a bit different. ears are not really sensitive to phase, so you won't necessarily notice that. I don't think it would cause any discomfort, because it is not adding any weird frequencies. However, phase distortion usually means you are near the edge of the amplifier's bandwidth, which means you are probably getting ringing on transients and fun stuff like that. Makes the audio muddy and gives audiophile editors lot's of stuff to write about. >I'm also curious about lab standards by which something as subjective as >perception is meaningfully quantified. Can anyone recommend a good source >for >info on that one? within the field of pshychoacoustics there are probably such things, but not really in engineering. Your typical lab standards in this regard would be Total Harmonic Distortion, or THD, and Intermodulation Distortion, or IMD. THD just tells you how much distortion you have when a tone is put through the system, but doesn't tell you much about what sort of distortion. IMD is similar, but measures the degree to which two tones together in a system modulate each other and produce non-harmonic frequency components. Both are useful benchmarks for basic engineering practice, but neither really tells you much about whether it sounds good or not. You generally have to go well beyond that in designing serious audio systems. Marketing people like them, though. >>These inharmonic distortions add frequency components to the >sound in a >particular way that women tend to have a negative >reaction to while men >typically don't notice. > >Sarajane's post mentioned differences in inner ear structure between >genders. > Is that the mechanism in this case? I don't know. I would imagine there are neurological aspects as well. >Maybe it's just a difference in individual thresholds. I've run across a >very >few musicians who consistently choose to play at *significantly* higher >volumes think of the fingernails on the chalkboard thing. Some people roll on the floor in agony. Others smile malevolently as the slowly drag a long pinky nail across the board, apparently with no discomfort, while enjoying the suffering of others. Being the latter sort, I've noticed that women are usually more prone to it, but many men will also be affected. The worst I ever encountered was the guy living in the dorm room next to me in college....he would literally fall on the floor and roll around.... If you really do go research it a bit, let me know what you find out. kim ______________________________________________________________________ Kim Flint | Looper's Delight kflint@annihilist.com | http://www.annihilist.com/loop/loop.html http://www.annihilist.com/ | Loopers-Delight-request@annihilist.com