Ok so here's the deal, We're running a show on a new mac-OS Mojave version: 10.14.2 (3 GHz, Intel i5 Processor, 8 GB memory) and Using Qlab version: 4.4.4

We have the computer hooked up to our light board & sound system with a USB splitter and as far as I know the sound files are not stored on an external drive.

Sometimes when we go to trigger audio in Qlab the program behaves normally and says it's playing the audio cue, but no sound is produced by the house speakers. The sound system and amp set-up are otherwise behaving normally and doing everything else they aught to, but there seems to be some kind of disconnect or lack of communication.

The only way we've found to fix this problem is restarting the Computer, at witch point the sound cues play over the house speakers with no issue.

The scary thing is that this disconnect can seem to happen anytime with no indication that anything is wrong. A performance will be going along smoothly until suddenly we miss a cue right in the middle of things because the audio decided to play hooky in-between scene's 1 & 2. Then we have to scramble in the middle of a show to reboot the whole system before the next line is up.

The Qlab documentation seems to support my theory that its some kind of software snafu rather than something technical with our amp setup: https://figure53.com/docs/qlab/v4/general/preparing-your-mac/ - However as more of a PC user I'm not quite comfortable with making changes to the Terminal hoping it solves the issue. Rather I would like to nail down the exact source of the anomaly.

5/24 ... Ok so App nap is disabled, I checked the console messenger & the only recurring thing I keep seeing is "Remote Device Heart-Beat" --> Request ... Received. Not sure if that is related to the USB splitter or not. The power saving options prevent the screen from ever sleeping but I'm also noticing the boxes for [put hard disks to sleep when possible] & [enable power nap] are both checked, could those have an impact on Qlab performance?

I'm also now rather certain that the USB splitter is working exactly as it aught to, since when I unplug it Qlab kicks back an error and won't play the file. where as in all other circumstances including when the audio cuts out it visually appears and behaves as if nothing else is wrong.

Any advice in this regard would be great.

  • 1
    Could also be the USB device isn't keeping connection with the desk for whatever reason and the device is dropping out of the patch list. When it happens, can you still see the USB audio codec device in "Audio Midi setup?" – Mark May 21 '19 at 4:45
  • Any indication in the console logs about the audio device? – Mark May 21 '19 at 4:46
  • Next time it does it - launch Audio MIDI setup & flip the output of your device from 48 to 41 [or vice versa] & back again. My Line 6 has been doing the same thing since Mojave & that fixes it, til next time the screen sleeps. – Tetsujin May 21 '19 at 6:02
  • maybe make sure that QLab doesn't have 'app nap' selected? – Mark May 21 '19 at 12:10
  • Also one of those settings in 'preparing your mac' deals with turning off the screen sleep. – Mark May 21 '19 at 12:11

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