MOTUnation.com

grimepoch wrote:As an added bonus, I'll give you something to think about. Let's say your sample rate is 40kHz which tells you that nyquist says you can only represent signals to 20Khz. Now let's say you have two sine waves at 20Khz and you are sampling them. The first one, let's say it time aligns EXACTLY with the peaks of the 20kHz. Your resultant samples get two alternative values at max and min over and over.

Now, let's say that the sine wave was shifted exactly 90 degrees from that. The sampler would be recording values at the zero crossings. You would see nothing. Nyquist tells you can in fact sample at half the frequency, but what it doesn't say is that the nearer you approach the limit, the more inaccurate the amplitude can be recorded based on the phase of the signal and the phase of the samples. When working at the higher sample-rate, this problem is greatly reduced, however, when you go back down, if those samples are in the bits to throw out location, again it would disappear. If you tried to look at the samples before and after, you'd see maximum amplitude and minimum, which would still put you at zero. (given PERFECT timing and recording of the a sin at 80Khz just to coincide with the example of 40Khz above).

martian wrote:what kind of conversion you need?

I looked at barbabatch but seemed pricey

I'm using sound grinder which is much cheaper - and has some pretty useful functions I think -

And is a try before you buy scenario - which in this age of software is good.

I mean we've all bought stuff and found it doesn't really work as advertised...

There's also audiofinder which does conversions too

wow you dug this thread up pretty deep!

martin