Re: [linux-audio-user] Firewire devices and Linux

From: Paul Winkler <pw_lists@email-addr-hidden>
Date: Fri May 12 2006 - 19:56:07 EEST

On Fri, May 12, 2006 at 06:32:01PM +0200, Pieter Palmers wrote:
> Paul Winkler wrote:
> > (re. presonus Firepod latency)... what kind of latency are you getting
> >with it?
> >
>
> The current freebob code + recent firmware should give you around
> 350frames of latency at 44100/48000 (about 7ms). Round trip including AD
> / DA, measured using jdelay.

Not bad at all!
I haven't measured with jdelay, but if I understand correctly,
round-trip latency is d + (p + p*n)/sr, where p is the -p
arg to the jackd backend, n is the -n argument, sr is the sampling rate,
and d is the latency introduced by DA and AD conversions.

Assuming d is about 1-2 ms, that means you're running with
something like jackd -d alsa ... -p 64 -n 3
or -p 64 -n 2 ?

If so, that's really pretty nice, I haven't done any better
on my delta 66 (but I haven't tried aggressively to go lower).
I can sort of run at -p 32 -n 3 (3ms + d) but I get dropouts.

-- 
Paul Winkler
http://www.slinkp.com
Received on Fri May 12 20:15:11 2006

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