[PD] latency solutions... and then some

colet.patrice at free.fr colet.patrice at free.fr
Sun Jan 31 16:12:21 CET 2010


Hello,
latency delay is noticeable at ~25ms, below there are artefacts grain caused by
phase decay if the source and the processed signal are played together at the
same place with almost same amplitude.

 11ms is only the buffer size, and other elements
in sound processing need to be taken in consideration like the distance
expressed by the sound speed in the air (about 340m/s at sea level 15°C), so you
can add about 3ms per meter, also almost all effects needs a processing window
so the more processing power you have, the lower the achievable latency.

 Any other digital processor added to this chain would add latency, like digital
guitar pedals and amplifiers.

 The dsp needs realtime access, so the Operating System have to be configured
for giving high priority to PureData, and a low latency audio driver needs to be
used directly from pd or through jack, anyhow there are much possibilities with
jack server.

Selon Pierre Massat <pimassat at gmail.com>:

> Hi Jeffrey! I ve been trying to minimize latency in Pd for a year now,
> experimenting with various OS and hardware. I m using Pd for the same
> purpose, that is live processing of electric instruments (mainly a guitar).

> 2010/1/31 Derek Holzer <derek at umatic.nl>
>
> > "Unnoticeable" latency usually refers to the musician not noticing the
> > difference in time between when they press the key and when the sound comes

> > even the un-processed signal goes through Pd to avoid echos or comb
> > filtering due to latency.

> > Jeffrey Concepcion wrote:

> >>      type of effect)? i've read that 11ms can be achieved and is
> >>      unnoticeable.







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