[PD] timing question

[Charles Henry]

On Dec 17, 2007 3:03 AM, Frank Barknecht <fbar at footils.org> wrote:
> Hallo,
> 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.

My mistake.  I thought messages had to run in between dsp blocks.

>
> > 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~!

I see now.  That works well up to 1000 Hz.

Chuck

>
> Ciao
> --
>  Frank Barknecht                                     _ ______footils.org__
>
>
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