Dolby Digital/Rock Band -- What receiver adjustments will prevent missing notes?

I'm having an issue with the Dolby Digital setting in Rock Band 3, played on a PS3, hooked up to an Onkyo HT-R530 7.1ch receiver (part of the HT-S5300 HTIB). The game sounds awesome in Dolby Digital, and once auto-calibrated hit notes are registered accurately (ie, I do not have a 'lag' issue). But at points throughout any given song the strum bar and fret buttons will suddenly not be responsive at all--I don't even hear the chirps and squeals indicating that I'm missing the notes. Even if I pause the game, I momentarily cannot strum up or down to quit or restart the song. It only lasts a few seconds each time before hit notes are registering again, but it's usually at least a few times per song, and is obviously quite frustrating. I'm using a new MadCatz RB3 Fender Strat, with fresh batteries and when this happens the red light on the dongle stays solidly lit the whole time. So I can rule out a connection issue. And I've tried a different guitar, with the same result.

In the rockband.com forums, an admin offers this general tip to deal with this issue when it happens:

Also try turning off Dolby 5.1 in the game options or bypassing your external audio system to see if this resolves the issue. If it does, try troubleshooting your audio setup to limit or resolve the issue.

When I turn the Dolby Digital off in-game, and restart a song, this does seem to correct the issue. BUT I don't want to turn off Dolby Digital, given how awesome it sounds when it's on (at least before I start getting booed in surround sound for missing so many notes.)

So, my question is: Does anyone have any experience or advice on how to "troubleshoot your audio setup to limit or resolve" the Dolby Digital/Notes Not Picking Up issue? And not necessarily specifically with an Onkyo HT-R530 receiver, but generally? Are there any known common receiver features/settings (like Audyssey, for example) that cause issues with Rock Band? Does it have to do with what dB levels speakers are set at? I'm stumped--I've tried changing a few settings but nothing seems to make a difference. And this seems like too specific / unusual of an issue that I think it's probably doubtful that Onkyo customer service would even have an answer or suggestion for me. (and from what I've read on these forums their customer service isn't great anyway)

Any insights would be appreciated!

Thanks for the reply Roger.

Quote:

When it becomes unresponsive, does all audio go dead silent, or just the ability to trigger certain notes--and the background sound remains live? If there is any audio still playing, it appears the DD encoder and decoder are both still working.

The background audio (other instrument tracks and crowd) still plays fine. The guitar I'm playing with just becomes suddenly and temporarily unresponsive. It seems to happen at random...if I play the same song twice, it won't happen at the same point in the song.

Quote:

It seems that turning off DD encoding may be reducing stress on the PS3 internal processor. Maybe a similar benefit could be had by unloading other stressful options, like rendering in HD video?? Just a wild guess.

Is this common? I've never had an issue with my PS3 getting over-stressed with any other game, and I don't recall reading about such an issue. It's an 120 GB Slim model, probably about a year old, with plenty of space on the hard drive...I don't think I've done anything excessively punishing to the machine itself, other than I suppose put it through its paces with Rock Band. And if playing high-def video and DD simultaneously would affect performance, why would that even be an option? Seems PS3 users would be up in arms about something like that. I think/(hope) I can rule that out.