[PD] timing question

Frank Barknecht fbar at footils.org
Mon Dec 17 10:03:10 CET 2007

Charles Henry hat gesagt: // Charles Henry wrote:

> [metro 1] creates a bang each millisecond, approximately.  The message
> rate is constrained by the block size, so you would want to put [metro
> 1] inside of a subpatch with [block~ 1] for best time resolution.

That's not true. Message rate is not related to the dsp vector size. 

> You can't get your messages to resolve at *exactly* each millisecond
> in pd, no matter how you do it-but [metro 1] gives you 1-ms bangs with
> an error of at most 1/44.1 ms, using [block~ 1] and sampling freq 44.1
> kHz

> --I guess if you use a sample rate that is a multiple of 1,000 you can
> get exactly milliseconds between bangs.

Of course every action in an digital audio system has to happen on a
sample, but Pd's clock-delayed messages calculate time as a continuum
(in float-resolution), not quantized to samples, so they are able to
calculate times in between samples. And again: You don't need any
[block~ 1] to get that accuracy in metro. Try it yourself with a
phasor~-clone build from metro and vline~!

 Frank Barknecht                                     _ ______footils.org__

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