Try a “Mixdown” of the Audio for playback before you dub out of FCP, or DURING the edit, if you have audio/video slipping, drop-outs or freezes.
NOTE: Mixdown has even been demonstrated to help with slipping, skipping problems (or “missing” audio clips) for files being EXPORTED as QT (or similar) files out of FCP.
First, SELECT ALL of your audio tracks (highlight them) on the timeline, then:
Sequence Menu > Render Only > Mixdown.
You should see a dialog box telling you its rendering.
It might seem to make little sense that “Mixing down” even simple audio tracks will “fix” complex video “freezes” or random audio dropouts to tape or export, but it CAN.
NOTE: It does not matter of you only have one audio track, if there are random freezes during output, you should try the Mixdown.