Re: [LAU] Fluidsynth, soundfonts, jack, and latency

From: Jonathan E. Brickman <jeb@email-addr-hidden>
Date: Mon Nov 02 2009 - 15:17:59 EET

Guru, do you know what was/is the CPU load during the episode?

J.E.B.
> Hello everyone,
> So I've been trying out AVLinux. By the looks of it, quite impressive
> - but I soon ran into a rather serious issue, but I doubt whether it has
> anything to do with AVLinux or not. I need your help in this knowing for
> sure.
>
> My usual setup involves a piano sample on Linuxsampler and a strings
> soundfont on qsynth. I had an unusual gig last week that required no
> piano sounds, but instead use of multiple layered samples. I therefore
> used only qsynth, with 3 engines running concurrently. So in my brand
> new AVLinux setup, I loaded up my samples, and had sooperlooper running
> 2-3 loops concurrently, all on a core2-duo macbook.
>
> Initially, all was ok. No noticeable latency, no xruns whatsoever.But
> during the rehearsals, this happened: after sometime, specially at some
> point when sooperlooper was running full steam, suddenly there was this
> HUGE latency, coupled with lots of dropped notes. As in, I could hold
> down a dozen keys simultaneously on the midi controller, and not all
> notes could be heard; those that did, would be heard at various
> instants upto about half a second later. Completely unuseable.
>
> This would persist even after restarting the jack server, but dissappear
> on rebooting the OS.
>
> To me, what is scary and irksome, is not (only) that this glitch
> happened consistently, but that there were no error messages in the
> qjackctl window. No xruns. Nothing that suggested that something had
> gone terribly wrong somewhere (which it had).
>
> I actually compromised on my gig sound, by offloading a lot of samples
> what I wanted layered. I don't know if it was because of this, but I
> didn't notice this particular issue on the gig itself (but it gave me
> sleepless nights prior). But then, 5 mins before the start of the
> program, I was left with no audio out of my system! (again, no error
> messages). Restarted jack server, and everything back to normal.
>
> Again, no error messages/warnings. Not so much as a by-your-leave. ;)
>
> I'm now intent on finding the source of the problem. I'm looking for
> pointers... where do I begin? Where's the 'smoking gun'?
> Thanks in advance!
> Cheers,
>
> Guru
>
>
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>

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Received on Mon Nov 2 16:15:01 2009

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