Hearing Damage over 20khz?

Someone had a link to a group of reviews of 24/96 downloads and did detailed examinations of the information and the spectal analysis.
The results showed no recordings downloaded had any information in the added high definition areas of the downloads, so they were basically Cd stadard downlaods.
Then some that did have 'something' the information was things like a TV in the area, as the signal at the exact hi frequency ultrasonic squeal of a video tube dispay.. etc.
So the information in a recording over 20,000hz, while theoretically interesting, is of zero practical application.
And is entirely of 'crap' that is present in the recording area, and not even from the instruments etc..
As no one tries to 'quiet' Hf noise over 20,000 hz no one can hear anyway...

Mr Jgiacalo- I'd have thought anyone with a knowledge of musical instruments, and/or accurate music reproduction, familiar with(or, at least conscious of) the facts contained in the second site you mentioned. I guess not! Frankly- I'm glad YOU mentioned it FIRST!

The issue is not wether we can hear anything above 20khz, or wether this information is present in recordings; although, wether we can "hear" it or not is very much up for debate, given recent research. The real issue is how the absence of that information (above 20khz) affects audible information below 20khz.

Subharmonics, also known as undertones, are a very real part of the harmonic makeup of all music. They occur naturally as a result of the interactions (which can be quantified mathematically) between two or more fundamental frequencies, and it is an acoustical phenomenon that occurs at all frequencies ranges, including the "inaudible", above-20khz range. I remember playing flute trios in music conservatory, and being amazed by the appearence of a fourth, "phantom" flutist at certain points in a composition. At certain points in the music, due to the particular musical intervals being played, and the fact that the flute produces a relatively pure tone, a fourth tone would be generated below the lowest written tone, with every bit as much power and presence as the written tones; clearly audible to listeners as well as the players.

Why then, should it be difficult to appreciate that the removal of these harmonic interactions in the above-20khz range would have a significant effect on harmonic content in the audible range? The removal of a portion of this infinite "matrix" of harmonic interactions by the recording process would surely have an effect on perceived timbre, and spatial cues. And that is but one reason why our precious recordings will never sound quite like the real thing. I think we tend to underestimate the incredible complexity of music and acoustics, and miss the forest for the trees.

Actually, I'd be very surprised if most of us here could hear 16khz tones forget about 20khz.

Thanks for all of the input. I feel more at ease about the supertweeters on my KEFs with my kids around.

One thing is for sure, humans are exposed to many things today that we never were in decades or centuries past so the long term effects are difficult to predict.

Thanks again.