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Hearing Damage over 20khz?

I own speakers that produce in excess of 40khz, yet the human ear can only perceive 20khz.

If something is uncomfortably loud we can hear, we know to turn it down but what if the frequency is out of our audible range?

Is it possible hearing is being damaged by something we can't hear?

I have read reports of people having ears ring after using speakers that can go beyond 20k, but I don't know if it's due to the sounds produced below 20k or above or both.

It would be horrible to learn I was damaging my children's ears or mine without knowing it.
vintagegroove

Showing 4 responses by eldartford

eldartford
4,262 posts
 
Measurements of hearing (eg:20KHz) are based on sine waves. But lower frequency waveforms that are not sinusoidal can have wavefronts with slopes well in excess of the fundamental frequency. I believe that the ear detects wavefront slope. You may not hear a 30 KHz sine wave and yet limitation of slew rate to that corresponding to 20 KHz sine wave is audible.

I have experienced exactly this effect, except that, at my age, both frequencies are lower.
eldartford
4,262 posts
 
Shadorne... And there are woofer hairs, midrange hairs, and tweeter hairs. However, the ON/OFF mechanization can represent waveform as well as frequency.

What is your explanation of ability to sense the existance or absence of frequencies higher than measured sine wave sensitivity?
eldartford
4,262 posts
 
Shadorne... I am very familiar with Fourier analysis. (I used it a lot in my role as a test design engineer).

Evidently you have not experienced the phenomina which I described. The ongoing interest in supertweeters is further evidence that frequencies above the measured hearing range do matter.
eldartford
4,262 posts
 
Shadorne... Agreed... "there is no evidence that we can actually hear pure tones well above 20 KHz".

But we can detect the presence or absense of such tones. Perhaps this is because of beat frequencies as you suggest.

Listen to a 20KHz square wave and a 20 KHz sine wave. I bet you can tell them apart(if you can hear them at all. If not try a lower frequency). The only difference is the higher harmanics in the square wave.
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