I'm also having this issue. I've looked at all the configurable settings but there's nothing apearantly wrong. All the tracks are checked... looks fine. I'm not totally familiar with a couple things in there. I'll try going to V 14 unless I hear that the 16 beta has fixed this.
Here's my settings:
MacBook Pro 17" i7
Audible sound in redcine 15
No Audible Sound on Pro Res playing through quicktime 7
In the Quicktime Audio Section:
Format: Linear PCM
NO advanced settings (not possible)
Linear PCM Settings: Sample Rate 24 bits
Little Endian Unchecked.
All boxes below that are dimmed.
And then for the Audio TAB in the Edit (export) Preset window:
Camera Audio Channels 1-4 all checked
External Audio Channels: 1-8 All checked.