if i only run a 5.1 set up, will i miss any sounds on br discs with 7.1 pcm sound?

If you are running audio through analog, yes. If you are using HDMI, then I think not... it will mix the rear center channels into the 5.1.

cool thanks. currently running neither atm as i have a ps3 and receiver doesnt have hdmi. looking at getting the onkyo 605.

How many Movies in 7.1 atm
;)

Only two HD discs, both Blu-ray, seem to be true 7.1 mixes: Ghost in the Shell 2 and The Avengers anime and cartoon features.

Some 6.1 PCM tracks will be decoded as 7.1 PCM with the mono back channel duplicated... perhaps the manufactures think receivers or pre-amps will wig out with 6.1 and not know what to do if you have 8 speakers.

Dan

Dirty Dancing shows on my PS3 as 7.1 PCM. The packaging says 6.1 PCM. I only use optical so I couldnt tell ya. Also this is the only disk that I have ran into that defaults to the PCM track instead of the DD. Nice that my reciever matrix's the 2 channel PCM to my 6.2 setup.