Sync issue using external audio card

[David_Fine]

I just plugged in my Avid Mbox, which I use for Pro Tools, but also all audio output from my iMac. Working in TVPaint, I just noticed that when I play back using preview, the audio plays about half a second late, so really late! I eventually tried switching my audio output back to the Mac's audio and now it plays just fine. Thing is, the sync issue does not happen in any other application outside of TVPaint. Not Pro Tools, or Final Cut Pro X. So while I imagine this might seem to be Mbox related, given that it only happens in TVPaint, I wonder if anyone has any thoughts on why this could be the case. It just means I have to switch outputs when I am using TVPaint, which I would prefer not to do.

[Fabrice]

sorry, but we don't have this card to run some tests

[David_Fine]

I suspected not, but does the notion of an external audio card like this causing sync issues make any sense? It is a USB interface. I wonder if you have any insight into this kind of thing ever being an issue with any kind of external audio card.