QLab / 2010 MacBook Pro / FireWire / X32 SFX Playback Audio Distortion?

Simon Eves

Sophomore
May 12, 2013
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This past two weekends, my X32 has been in use on a production of RENT, with a 2010 MacBook Pro 13 running QLab for sound FX, 4 channels in to 33-36 on the board, over FireWire Card 1-4, using a 6' FW800/400 cable.

On Saturday night (of course, a night I wasn't there) they had a problem whereby the sound effects playback was suddenly "possessed by a demon", with huge digital distortion, although apparently the content was still recognizable and silence was still silence. This was despite having tested the cue playback about 20 minutes earlier.

They pulled and replaced the FireWire cable, in the hope of "resyncing" the connection, but that didn't fix it. They then waited for a longer gap and rebooted the computer, after which everything was fine, and remained so for the rest of that show and for the final show yesterday.

The board is running v2.05, but with the original XUF firmware (I never bothered installing 8412 as it was documented as affecting USB connections only).

I have used this exact set-up many times in the past, sometimes also running Reaper in the background for a multi-track recording, and never had a problem.

Any thoughts?
 
Re: QLab / 2010 MacBook Pro / FireWire / X32 SFX Playback Audio Distortion?

I don't know about macs but on windows the windows sound system may cause lose sync if windows is using a different configuration than asio. This goes for any soundcard in general.

Due to this it is important to not have the system sounds routed to the x32 when asio is in use. Is there something similar with osx?