I watch the mission, but I'm having two sound problems. One, no music. Yes, music is turned on. I hear music if I play a mission from the FreeSpace 2 campaign. Either the build I'm using (3.6.9) doesn't support ogg vorbis, or I'm doing something wrong. A weirder possibility is that it's some sort of hardware/driver issue. I can play the music successfully with VLC media player.
The other issue is that only small amount of the weapons fire is heard, and frequently I only hear bits of it, as though a beam started to power up, but was cut off. Perhaps part of this is to do with the distance the ships are from the camera, I don't know how FS2 handles that. Again, seems fine in the FS2 campaign, but I haven't properly tested the distance issue.