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Re: [microsound] High sampling rates/Bit depths

From: Aaron Ximm <ghede@xxxxxxxx>

2) Nyquist is good only for determining maximum frequency of square wave;
any wave shape differences are obliterated -- even a 5 Hz tone has very
few samples to differentiate a sine from a saw from a square at 44.1.
Personally I start losing ability to discern those things in high
frequencies but it'd be a useful test to render some simple waves at high
frequencies and then try recording them at different sample rates...

This is incorrect. At 44.1k, digital audio recreates a 22k *sine* wave, not a square wave. The reason this is important is that all sound is made up of sine waves. So the 22k square wave you're talking about is really a 22k sine wave with added harmonics above 22k. The reason you lose the ability to discern the difference between a square and a sine at those high frequencies is that your ear is filtering out the higher harmonics so you only hear the fundamental that is in your hearing range. Likewise, the filters in an AD converter filter out the unneccessary upper harmonics in the 22k square or saw wave (or other complex signal) leaving only the 22k fundamental sine wave.

So though it seems counterintuitive, a digital to analog converter needs only 2 samples to accurately and perfectly reproduce a sine wave. There is the high point and the low point and the stuff in between is always a sine. That's why the max frequency captured is 1/2 of the sampling rate.

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