Re: [FFADO-user] Lower latencies on FA-101 with FreeBob

[Stijn v. B. <sti...@gm...>]

Thanks again for the reply. 4.35ms is better than good enough indeed.. I got
confused because I heard a rather big delay when tapping my mic and patching
it to output directly through SuperCollider. It turned out I hadn't set the
priorities of my rtclock and firewire device IRQ properly.  I fixed that now
and there's no noticable latency anymore. Sorry for the confusion...

Stijn.

2008/1/18, Pieter Palmers <pi...@jo...>:
>
> Stijn van Beek wrote:
> > I got FreeBob running stable now using a FireWire expresscard (Texas
> > Instruments chipset) on my DELL Inspiron laptop. Seems to work fine with
> > a frames/period 64, periods/buffer 3. I don't seem to be able to go any
> > lower than the 64, because jack stops giving audio output when I try.
> > Also QJackCtl refuses to lower periods/buffer to 2. Some hints would be
> > greatly appreciated because I would love to lower the latency under the
> > 4.35 msec that I get now.
> > Thanks Pieter and Mysth-R for their advice so far. (Mysth-R: I had to
> > upgrade my BIOS indeed to get the expresscard to work..) Cheers,
>
> Lower than 3x64 is not going to work.
> Please note that:
> 1) you're already at latency figures that can't be met by Windows (bad
> design) nor by MacOs (by design).
> 2)Apple considers everything < 10ms as 'good enough'. And the audio
> pro's seem to be very happy with Apple.
>
> 3x64 will have to do for the moment, and to be honest for me it's not a
> priority to push the code lower than 3x64. Once we are at that latency
> level, I consider it low enough and rather spend time at expanding
> functionality and device support than optimizing latency. My experience
> tells me that there is an exponential increase in complexity when going
> to lower latencies.
>
> Greets,
>
> Pieter
>
>
> >
> > Stijn.
> >
> > 2008/1/17, Pieter Palmers < pi...@jo... <mailto:pi...@jo...>>:
> >
> >     Stijn van Beek wrote:
> >      > Hello,
> >      >
> >      > I am running Jack on Ubuntu Gutsy with the rt-kernel. I 've got
> an
> >      > Edirol FA-101 connected using FreeBob. The problem I am
> >     encountering is
> >      > that Jack zombifies randomly. The lower I make the buffer
> >     size/number of
> >      > periods the sooner it zombifies. I am running Ubuntu on a DELL
> >     Inspirion
> >      > 6400. The chipset is R5C832 (Ricoh). I already tried the rtirq
> script
> >      > and following the instructions Pieter Palmers gives on the
> FreeBob
> >      > pages. Also I added the following lines to
> /etc/security/limits.conf:
> >      >
> >      > @audio - rtprio 99
> >      > @audio - memlock 512000
> >      > @audio - nice -19
> >      >
> >      > I read in an earlier thread in the archives that this Ricoh
> >     manufactured
> >      > chipsets might be buggy. Should it help to buy a Firewire Express
>
> >     card?
> >      > Or are there any other solutions? Thanks,
> >
> >     This sounds like the Ricoh chipset problem indeed. If you can get
> hold
> >     of an expresscard or cardbus controller, please try it.
> >
> >     The FA101 should work fine with freebob, and people have been using
> >     freebob + ubuntu without problems for a while now.
> >
> >     Greets,
> >
> >     Pieter
> >
> >
> >
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