When doing a new install (dvd i386) of RC1, I did notice the volume in the AV setup wizard was around 20% instead of the usual 80% area. I changed it there in the AV wizard. I've just played one video and the volume was fine. Audio is SPDI/F optical to an uncontrolled AV Receiver (it's unsupported so have to manually create it).
I did notice that starting with beta 4 and still in RC1, that when starting the KDE desktop, the initial desktop is ready sound is badly saturated (major clipping).
Also DTS volume worked in the AV setup wizard! Whooop!