I don't know if this is in the right place, but, does Dolby Prologic II work with analog cables. Would the sound be better if I used a digital optical cable instead?
Are you talking about coming out of a sattelite or cable box? If so, in my experience with the sources I've had,(Replay TV, cable box, & sattelite box)the digital output always sounded the best to me. The receiver is doing the processing in the digital domain anyways so in most cases it would be better to send it in that way. Of course, there might be exceptions with some types of equipment, so you might want to experiment just in case.
Whether it receives it in analog or digital, a 2 channel or Dolby surround signal is going to be processed and matrixed out to surround with DPL II by the receiver if you have it set in that mode.
Dolby Surround is stereo only, regardless of digital or analog connection, and PL, PLII are able to extract channel information from the signal. Dolby Digital is not the same thing as Dolby Surround, but with a player that has built in decoding, you can still get true 5.1+ surround via analog cables. Which one will sound better depends on which has better DACs (Digital to Analog Coversion) and bass management. Typically, the receiver will do a better job.
I knew DPLII was used to make stereo sources into surround sound, but I was wondering if the sound would come out better if using digital cable, instead of analog. Anyway, you answered my question.
Pro Logic, DTS NEO:6, "Lexicon's" Logic 7, and others do an amazing job of splitting two channels into 5, 6 or 7 but they can't compare to true Dolby Digital and DTS. There is a pretty big difference. The sound is clearer or "pin-point. With the others it can sound a little hollow or echoey.