[PD] Pd sample rate and audio interface

Burkhardt Reiter ror20 at pitt.edu
Thu Mar 6 18:37:46 CET 2014


General (Pd-101?) question about how Pd talks to the audio interface for 
sample rate agreement.

On my system - OS X 10.9, Komplete Audio 6 interface, pd vanilla 45.4 - 
I can set Pd to a different sample rate from my interface, yet not 
achieve the expected transpositions from having unmatching sample rates.

Within Pd, I have soundfiles recorded at 24, 44.1, 48, 88.2, 96, and 196 
rates. When I set Pd to a sample rate other than the rate of the 
recorded file, the playback transposes as expected from the differing 
sample rates...i.e. the 44.1 file plays back at a higher frequency when 
Pd is set to a sample rate > 44.1.

What I was expecting was that if I deliberately unmatch the sample rate 
of my interface and Pd, that the sonic output would be similarly 
transposed due to the sample rate in-equality. However, it seems that I 
can set my interface to any sample rate, set Pd to any sample rate, and 
the sonic output will be stable - a 440 osc~ will sound like a 440 osc~ 
- rather than transposed as stated in the Pd documentation section 2.4.1.

I get the same stable results when Pd is set to output via my iMac's 
internal sound processor, too.

I was hoping to use the unmatching sample rates between software and 
hardware as way of illustrating the necessity to have the sample rates 

Thoughts, suggestions, or clarifications?


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