Oh, I wish I lived in a suburb where I saw an 8yo working 60" plasma TV "REGULARLY" lying around on the side of the road.
You're so lucky, where do you live. What planet is that again?
Never mind. I don't really care.
These came out at add ons to stereo separate systems. My first real bit of HiFi was a Pre-pro/Power amp from Kenwood that I bought back in 1989. The surround processor connected to the Tape 2 line level loop. The LD or HiFi VCR was connected as normal to the main pre-amp, and the Tape 2 out sent the signal to the processor, then the processor sent back the now extracted L and R channels. It only had small amps for centre and surrounds.
My first surround sound processor was a dinosaur from Pioneer. Although this thing did have pre-outs, there was no SW out or bass management. Trim adjustments were really course in the way of 2dB increments. The Dolby Pro-Logic Chip set however was better than the later upgrade that came with my AC-3 pre-pro.
I added a Rotel 5CH THX certified amp and it used to play pretty loud.