Music by Scott Martin

SM Blog

Pro Tools and the mysterious vanishing audio

I’m currently running Pro Tools 9.0.6, and I’m not going to upgrade until I’ve finished my current set of mixes. If you’ve read any of the rest of this blog, that might elicit a chuckle, but I’ll have you know that I’ve got 50% of the mixes done dammit.

In any event, while working on one of the remaining songs I consistently ran into an issue where audio from PT would disappear at a specific time in a particular session. So here’s how the workflow went:

  • Load the session
  • Start playback (audio is, well, audible at that point)
  • At 1:45 in the session there would be a “click” and all audio in the session would disappear – even though the meters showed signal for all tracks for the rest of the song
  • Once the audio vanished, there was no audio regardless of where I tried to subsequently start playback – just another “click” and then silence
  • Audio would return if I reloaded the session, but the same thing happened every time at 1:45
  • Playback for other sessions worked fine with no issues

So much for being creative, right? Time for troubleshooting.

I knew that it wasn’t a problem with the physical cables or outputs because all other sessions played correctly. It was only this particular one that had the issue at its specific time. After audio disappeared, there was nothing from speakers or headphones.

I checked to make sure there wasn’t a specific region that started at that exact time (there wasn’t) and that there were no events that happened at that point (tempo changes, meter changes, no noticeable weirdness with sample rate, etc.).

The next step was to disable every plug-in in the session. I disabled all of them, and as I was doing that I heard a “click” and audio became available once again.

It turns out that it was a stereo instance of the Bomb Factory BF-2A compressor plug-in that was on the bus for the toms. There are no other active instances of it in the session, and it hasn’t caused any problems in other sessions, so I’m at a bit of a loss trying to figure out why the problem was occurring. But it was clearly the problem as I toggled it between enabled and disabled and heard the audio for the entire session disappearing and then reappearing.

BA-2A on the tom bus
Caught in the act!

So, I guess the moral of this story is: if you run into a PT problem and have eliminated most other causes, disable your plug-ins and see if one of them is the culprit!