[PD] bang~ event resolution

Martin Peach martin.peach at sympatico.ca
Sun Jun 21 03:28:14 CEST 2009

brandon zeeb wrote:
> Hello,
> With regards to the block limit thread and the following previous 
> discussion [1], I have a question regarding event timing resolution in 
> Puredata.
> In the previous email thread, it was noted:
>     What is also interesting, is that i get the double value of 2.9 msec for 
>     blocksizes above 64, for example 65 and above. There are no adc~ or dac~ 
>     objects or any subpatches in this setup.
> Does this mean that the resolution of a bang is in _multiples_ of 
> 1.45msec? 
> For example:
> 1. If I am attempting to send a message every 8msec (5.51 dsp blocks), 
> will the event actually be sent, rendered, and perceived to occur every 
> 8msec or will it be rounded up to the next block ( #6 ) at 8.7msec?
> 2. If an event is scheduled to occur every 1.50msec, will it be 
> scheduled in time every 1.50msec or every 2.90msec?
> I've read the pertinent section of Miller's "Theory and Technique of 
> Electronic Music", but I guess this is one small bit I'm still hung up on.

It averages out to the interval you specify (as long as the interval is 
longer than an audio block), but time is quantized to the duration of an 
audio block, because messages are sent at the end of the audio block 
during which they logically occur.
So in case 1 you would get a sequence of 5 and 6 block intervals that 
averages out to 5.51.
If your message rate is faster than the sample block rate you get 
multiple messages arriving at the same time.


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