[pd] 100000hz+

derek holzer derek at x-i.net
Thu Oct 26 11:45:20 CEST 2006

Well, first it would depend on the sampling rate that computer uses. 
Anything over half the sampling rate "wraps around":

PD -> 3.audio.examples/C01.nyquist.pd

This wrapping (i.e. foldover) is inharmonic, since it's reflected (i.e. 
aliased) back down the spectrum at the same rate that our pitch 
perception goes up it. That's why the tones you hear don't sound as 
"musical" as the notes would indicate. I'm (not even) guessing that most 
all the sounds you are hearing are these aliased frequencies, and this 
would be different depending on the sampling rate, as well as whatever 
lowpass filters exist in the sound card.

Short answer: yes, aliased frequencies would sound different on 
different computers, and that's generally why they should be avoided.

If you wanted to reliably synthesize the same result, you could do the 
math yourself (based on the difference between the frequency you want 
and your current sampling rate subtracted from that sampling rate), so 
that you would deliberately produce these aliased frequencies.


hard off wrote:
> i just made a synth which makes some really nice tones when i feed it
> really high frequencies.  (midi notes 150-300)
> question is, will this sound the same on all computers, or do
> different systems handle such high frequencies differently?

derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 175:
"What are the sections sections of? Imagine a caterpillar moving"

More information about the Pd-list mailing list