Sampling rates higher than 44.1Khz? Options

[Grand Dizzy]

I recently met a musician who claims he can quite easily hear the difference between 44.1KHz and 96KHz.

This shocked me a little because I'd always been told that the human ear cannot hear any higher quality than CD (44.1KHz) quality.

So... was this guy just lying (or fooled by his senses), or was I being lied to when I was told the human ear cannot hear any higher quality than CD?

This post has been edited by Grand Dizzy: Feb 5 2006, 01:11

[SebastianG]

This thread is fascinating! But most of it is too techy for me unfortunately.

Could anyone try again to explain how these byproduct tones/beats come about? And what is the low pass filter's involvement in this? (What is a low pass filter anyway?)

Fascinating? Hmm.... May seem so. But I think that some posts here are actually a bit misleading/misinformed.

Why may I hear something like that ?

[...] Mathematically, cos(32KHz)+cos(30KHz) = 2*cos(31KHz)*cos(1KHz). Add the time in equation and you have a 1 KHz harmonic with a variable intensity of 2*cos(31KHz*t). [...]

So what ? Just because there's suddenly a cos(1kHz*t) in a product you think you should be able to hear this one? Do you realize that you can also interpret your formula as a 31 kHz sinusoid with an amplitude modulation at a rate of 1 kHz ? Truth is: It does not matter whether a product representation contains usually audible signals. The first form (cos(32kHz)+cos(30kHz)) is the really interesting one. Why ? Because we've a bunch of filters in our inner ear (hair + hair cell) seperating frequencies -- every hair (depending on its location/length) has a certain resonance frequency and acts like a bandpass filter. From signal theory we know such filters are linear and time-invariant (LTI system theory, please check the linearity property on this site).
The linearity suggests that if you can't hear a single tone at 30 or 32 kHz, you also cannot hear anything when cos(30kHz*t)+cos(32kHz*t) is "in the air".

That's really interesting actually.  I just created a 96khz wav file with a 30k and a 32k tone and could hear a beat frequency as you say.  Though at 2khz not 1khz

This is likely due to one of these things:
- improper anti alias filtering of your sound reproduction system
- non-linear distortions of your sound reproduction system (including clipping)


edit: typos

HTH,
Sebi

This post has been edited by SebastianG: Feb 9 2006, 18:22