[quote user="gavsky"]
Specifically I'm thinking that it is down to how the left + right front channels are connected, as the 8.1s are bi-wirable: is it possible that if the cable connections are 'the wrong way round' on the speaker connections, then this causes the 605 to experience some kind of noise/feedback and so quits to prevent any sort of damage?
On the flip-side: my surround B&W 601s are also bi-wirable, so I as well as them acting as rear surrounds they are ALSO connected to a /separate/ Arcam stereo amp, which uses them as CD/radio playing. But the Arcam is always switched of when I'm watching DVD/Blu-ray (and hence utilising all speakers in the room) so I can't see how it would have any impact on the 605. Or would it..?
Any clues what the solution might be anyone?!!!!
[/quote]
Yes, it could be that the fronts are wired up wrongly, and thus causing the problem, but I'd be more inclined to think the rears are the problem, with the Onkyo trying to drive both the speakers and the output stages of your Arcam amplifier.
The configuration you have on the rears will be doing no good to either the receiver or your amplifier, and is really not what biwirable terminals are meant for. I suggest you rethink this aspect of your system, even if it means simply disconnecting one set of cables from the rear speakers depending on whether you're listening to music or movies.