I'm not sure why I'm having this problem, but I would like some advice on hooking up a TV Output (or GameCube) to Logitech Z-680 Speakers. The 4-page manual says that you need to get an adapter for the Red/White RCA cables into the green speaker cable, but that it will only be front speakers. I've tried using a Y-adapter: inputs of 2 RCA cables, output 1, then using an RCA-to-Mini-Stereo Plug adapter into the front speaker direct port (the green one), however this gives me 2-speaker sound, even on games I know are Pro Logic II-enabled. The only adapter I was able to find in stores was a Radio Shack "Stereo-to-Mono Audio Adapter: Accepts mono phono plug, Fits 1/8" stereo phone jack". The store personnel said that there may be adapters which are stereo, but they didn't sell them.

Speakers are, well, not my area of expertise (more into computers). Needless to say, I'm not quite sure what the proper way to hook up analog RCA sound to these speakers is. Any help?

Also, is there any noticable sound difference between connecting to a sound card with the 6-Channel direct Analog option and digital optical ports? The manual suggests using the analog cables included for 6-Channel direct, and that's what I am doing, but I'm quite able to switch to digital optical sound if it's reasonably better.