Hi,

I have an issue with audio breaking up when playing multiple files, as though there are intermittent gaps in playback. I am using QLab on a Mac Mini, connected using FireWire400 to a FireFace800.

All the source files are stereo, 24bit, 44.1k WAV or AIFF. If I play around 14 simultaneously the breakup problem occurs in varying amounts (never exactly consistently), mainly from outputs 1 and 2. The source files are being routed to various combinations of 16 outputs (both sets of ADAT outputs on the FF800).

There are no console or system log errors being reported, and no warning lights or loss of sync etc on the FF800 or the mixing desk. The FF800 is the word clock master (at 44100) and is the only thing on the FireWire bus.

14 stereo files doesn't seem a particularly difficult job for the Mac Mini. It's fitted with two SATA internal HDDs, one for OS and one for content. The optical drive was remove to fit the second HDD. Both drives are working and are 'MacOS Journalled' formatted. Weirdly, the problem is better if all the audio is run from the OS drive. But I can't believe I'm reaching the limits of drive transfer (or FireWire400) rates; by my calculations, 14 stereo 24/44.1 files need just under 4MByte/s transfer.

Everything is current aside from the OS: OS X 10.6.2, QLab v2.3.5, RME driver v2.9.3, FF firmware v2.77. The Mac Mini has 8GB RAM and is the A1283 model (the last before the unibody version).

More intriguingly, I have a backup Mac Mini in the rack, identically configured, which also exhibits the same behaviour.

Any advice appreciated! Is there a firmware update for the Mac Mini that I've missed?

Many thanks,
Matt