[PlanetCCRMA] Ardour errors during mixing

Fernando Lopez-Lezcano nando@ccrma.Stanford.EDU
Fri May 4 16:08:01 2007

On Thu, 2007-05-03 at 22:57 -0400, sara lidgey wrote:
> Hi All,
> I've been using Ardour with Fedora Core Linux now for a couple years
> without too many problems. I recently upgraded my machine (Intel Duo
> processor, 2 gigs of ram..., SATA drive) and I'm running Fedora Core 5
> with the CCRMA kernel 2.6.16-1.2080.16.rrt.rhfc5.ccrmasmp 
> I use an M-Audio Delta-66 audio interface.
> I've recorded a musical composition with between 20 and 30 tracks at
> 96khz sample rate. The recording went fine but now as I am mixing and
> adding the LADSPA plugin TAP Equalizer to many tracks, I am running
> into problems with either Ardour saying that ´...Jack may have
> disconnected because Ardour was not fast enoughˇ (most frequent error)
> or an error about Ardour not being able to read the disk fast enough
> to keep up with playback. I've noticed many xrun lines in the Jack
> messages window.
> Any advice about I go about solving this issue? Its getting to the
> point where I can't play back the mix for more that 20 seconds without
> an error. Are there any adjustments I can make to improve performance?

I imagine you have already tried to max out the size of the buffer that
jack uses (you don't need realtime response when mixing down, I think). 

Hmmm, what kind of hard disk do you have? Processor? Memory? It looks
like the disk subsystem is not keeping up. 

You could try to tweak some parameters in the /etc/ardour/ardour.rc
file. In particular:

    <Option name="minimum-disk-io-bytes" value="262144"/>
    <Option name="track-buffer-seconds" value="5.000000"/>

The later defines how many seconds ardour tries to buffer. You could try
upping that - it may give enough extra time for ardour to ride over
bumps in hard disk access delay. I don't know if it will be enough but
worth trying. 

-- Fernando