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What is the range of human hearing?

In the simpler days, let's say those of Audio magazine to provide an easy enough reference point, that range was said to be from 20 hz to 20 Khz. In fact, that was only good in younger people with good hearing. The linearity was far from perfect wihtin that range also, and middle-aged people, sometime after a life of working in a noisy environment, had measurable loss in the higher frequencies; 12 to 14 Khz being about as good as one could hope for at that age. Obviously the sampling rate debate has something to do with my question. I have read recently that humans may hear up to 23 Khz. This startled me, hence my question. I am not looking for theories or for explanations as to why cartridges should have a frequency response way over human hearing capabilities, or filtering in digital systems or whether tweeters should do more than tweet by sounding great to the family dog also. An answer on point is all I wish for.
pbb
rzado
175 posts
 
Zaikesman,

It is possible that such "intermodulation products" in the audible band may affect the perception of sound. As of right now, it is only "accepted" that the presence of ultrasonic content in combination with low frequency (i.e. conventional audio band) content induces activation of alpha EEG rhythms in the occipital region, which rhythms are not present when playing low frequency content alone. (See, e.g., Oohashi et al, Non-Audible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect, J. Neurophysiology Vol. 83, No.6). The mechanism for this is still being studied. However, some of the research being done now with the profoundly deaf is pointing to the conclusion that these in-band effects to which you are referring are not the cause (or the sole cause) of perception of such ultrasonic information.
zaikesman
3,017 posts
 
So Rzado your last point could indicate that the inner ear might not be the only region on the human body which can be stimulated by high-frequency sound waves. This of course is already known to be the case for low-frequency waves. This if true could be something that varies widely with individual physiology, but the "profoundly deaf" description also sends up a red flag - there could be exta-ordinary compensation going on in the brain here to extact any potential stimulus from the environment which hearing people may not perceive due to the way the brain develops. Who can really know? But I still doubt that any of these possibilities actually has something important to do with questions of concern to most audiophiles - for that, I'm betting on my first post.
rzado
175 posts
 
Actually, Zaikesman, I think you are conveniently misreading my post. First, the research I am disussing still points to the the ear mechanism (not "extra-ordinary compensation" as you claim) as being what perceives the ultrasonic frequency content. Second, your conclusion that "you doubt that any of these possibilities actually has something to do with questions of concern to most audiophiles" simply doesn't follow - in fact, it stands contrary to reason. It is not disputed that ultrasonic frequency content affects perception of sound - and, indeed, the ultrasonic content almost universally resulted in both more realistic, and subjectively preferred, sound. No one has been able to replicate this phenomenom with in-band frequency content. Thus, I think most audiophiles would absolutely be concerned with this reproduction of high frequency content.
zaikesman
3,017 posts
 
I was referring to the more theoretical of the possible mechanisms we're bandying about here, not the real possibility that ultra-sonic linearity might precipitate sonic gains in the audioband, which I don't doubt. :-)
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