I have the same problem when using Dolby Digital in the game Rockband.

When the in game digital setting is turned on, the sound of the AI bassist only can be heard; the player guitar and the AI vocals are muted out for some reason.

When i uncheck (turn off) the digital box in audio settings of Rockband, then all of the instruments can be heard. its the strangest thing.

This strangely started happening after the v2.40 system update. I have just installed v2.41 and still no fix for my problem.

I am a computer tech guy myself, but cannot figure this one out!

by the way, I use a Yamaha 7.1 Dolby Digital DTS amp, using all 8 speakers.

Craigerman