Yea I tried that, all rest are pretty much minimum but turned radio to 50% and I hear the stall warning (I think it was that) once but then no system/voice sounds after that at all inside the cockpit.
EDIT: Working now! Must have needed a restart. I just went back in to double check the sounds and they were all working. Ta.
EDIT2: Grr, ok all other sounds are working (and loud haha) now but the missle 'beep' is only in 3rd person view and it's very very faint still :(