Clean Mac OS Install latest Audition -- choppy playback

[johnr44409788]

Was suddenly having choppy / stuttering / dropouts playback in Audition, so I did a clean Mac OS El Capitan install onto another drive, with only Audition installed.  Nothing else running or installed at all.

The playback will stutter every few seconds using a Blackmagic Decklink PCI card for Audio out in using the latest Audition.

Quicktime player is fine, no issues.  I then installed Final Cut Pro X just to check and the playback is fine there, too.  So it's something in the Adobe world.

Did PRAM and SMC fixes to no effects.  Again, this is a completely clean install.  The buffer size is max size.

Okay, just wondering if anyone else is having the problem.  Thanks.

[ryclark]

I am not sure that the Blackmagic Decklink cards will act as audio only interfaces without video being present. The problem could be due to lack of proper sample rate Wordclock in order to drive Audition's playback engine.

[johnr44409788]

Thanks for the info.  I have tried with video and audio with the same choppy playback every 5 seconds or so.  I am currently going to update to mac OS Sierra to see if updating the OS will solve the issue.  Thanks.

[johnr44409788]

The upgrade to the latest macOS Sierra did not improve the choppy playback.  Again this is only in Adobe products using the Blackmagic Declink PCI card.  Other quicktime playback has no issue.

[Bob Howes · Accepted solution]

Stuttering is usually either a buffer size issue or a wordclock problem.  Since you have the buffer set to the largest possible size (nobody should have to do that) it might be worth checking if there's some kind of mismatch in wordclock--for example the Blackmagic card set to 48k for video while Audition is on 44.1k for standard audio or something.

The other thing to check for is that, despite what you say about a clean install, could there be something else running in background using some of the audio processing.  I'm afraid I could tell you how to check this in Windows but not on a Mac.

[johnr44409788]

I think this was ultimately correct that it was a clock issue.  But the solution was a bit obscure -- After trying everything, I changed the audio hardware input to match the audio output, and that completely solved the choppy playback stutter.  My Roland USB input device was borrowed last week, and Audition defaulted to computer line-in, which must have caused problems with the wordclock.

Thanks for all of the help!

[ryclark]

Aha. That makes sense. Glad you got it sorted.