It's not going to work, as composite audio cables are really only capable of stereo. So, you could use some sort of upmixing ability of a receiver, but that's about it.
Long story short, you'll need to get yourself a proper receiver with either optical or HDMI inputs.
Hi. I don't yet own a PS3, but I'm considering buying one, and I want to be able to use the system's surround sound capabilities. I have an LG surround sound system, however, the speakers plug directly into the DVD player (it's a one-box, which is a lower-end home theatre system, but mine is a high-end low-end, if you know what I mean). The DVD player has no HDMI or optical inputs/outputs, only composite ins. If I were using composite cables to connect the PS3, it would be easy - run the audio cables into the DVD player, and run the video cable into the TV, I've done it before. BUT, I have a HDTV, which means I'll be using HDMI to connect the PS3 to the TV. Would it still be possible to run composite audio cables into the DVD player from the PS3, and the HDMI from the PS3 into the TV? Do the composites even output in surround sound? And if they do, would the composite output still work with the HDMI output being used? Help would be much appreciated.