Minimum reasonable latency Was: Re: ZynAddSubFX was: Re: [linux-audio-dev] some new soundfiles on-line

Jens M Andreasen jens.andreasen at
Thu May 26 12:48:39 UTC 2005

On Thu, 2005-05-19 at 14:44 +0200, Tim Goetze wrote:
> [Jens M Andreasen]
> > A "synthesist" (that's my scenario), who can't hear *anything* before
> > the end of the pipe, would be very sensitive to jitter (the deviation,
> > or "sloppyness", between triggers and actual sound) and would therefore
> > require the smallest of small buffers.
> Trading jitter for constant latency can work well for some, too.
> Unfortunately the increasingly popular MIDI over USB connections 
> already introduce a millisecond of jitter, so if you're already 
> working at a blocksize of 64 at 44.1 or faster it's not worth the 
> effort.

Sorry for the delay (no pun intended!)

Jitter accumulates. So iff we say one ms(==USB) is clearly acceptable,
then every 0.1 ms above that value is drifting us away from the
acceptable range, no?

Moving from 64 to 32 samples gave me a penalty of about 10% efficiency.
The next step, going to 16 samples, raised the bar with 30%. So this is
where my application reached the intractable memory barrier. (And yes, I
have tried to manually preload, but Gcc/Intel Hardware is ahead of me
and already done that)
> Cheers, Tim

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