question for you audio people

[krispydude]

alright, i have a ps3 and an onkyo receiver however the hdmi is pass-through only on it. so my audio is connected by optical.

currently when i watch blu-ray on my ps3 and the disc has an 5.1 uncompressed or pcm audio i use that and switch my ps3 bd settings to linear pcm. i know only 2.1 channels can pass over the optical and then the my receiver must matrix the other 3 channles. for me this sounds better than regular DD 5.1. does this sound correct?

ok now my question are these other 2 audio formats being used now.

dolby trueHD - how does this compare to pcm? and would this be used under the bitstream setting in ps3? and does the whole thing pass through optical?

dts hd-ma - same as questions as trueHD

thanks for the help!