My set-up is a PS3 connected via HDMI to a Pioneer plasma, with optical audio going via a toslink switcher to a ~5-year-old Sony DAV-S550 home cinema system (with only one optical input and no HDMI inputs). Heres a link to my home cinema model in case this matters: Sony DAV-S550 Home Cinema System: Amazon.co.uk: Electronics & Photo Ive set the PS3 bluray audio settings to output optical 5.1 and DTS (both of which my DAVS550 can handle) and have selected DD 5.1 as the audio on the BD (3:10 to Yuma, not that it should matter). My DAV-S550 auto-detects the audio format and for normal DVDs and PS3 games switches to DD 5.1 and tells you so on the LED display. When I play a BD it just displays PCM and the audio is stereo only (with the sub). Ive tried playing with the PS3 BD audio output settings (on the PS3 itself), changing from PCM to bitstream, and turning automatic off. Ive also tried unchecking the two PCM options in the audio menu but these are both ticked and greyed out so cant be changed. Hope that all makes sense - this is driving me mad! Can anyone please suggest a fix (apart from a new HDMI amp) or a reason why this is happening? I'm not a complete noob but am not fully up to speed with the full menaing behind a lot of the bitstream and PCM terminology. Can I really not get surround sound from a BD with my current set-up? Any help or suggestions would be very much appreciated - thanks in advance.