Yeah! So basically, the analog surround formats (Pro Logic, etc.) that predate Dolby Digital work with those two stereo RCA cables. The Center channel signal rides on the inverted phase of one cable, the Rear channel signal on the other. Basically, any surround-capable receiver can decode that correctly with ease, and you’re in business. If you have a 5.1 setup, it will just duplicate the singular rear channel signal into both rear speakers, and of course anything below a certain frequency will be routed to your subwoofer as usual.
If you like your stereo receiver and don’t want to change it, there were add-on boxes, usually referred to as Surround Processors, that act as both a surround decoder, and a power amp for the surround speakers. They take the incoming signal, strip the Center and Rear channels out, amplify those (with their own gain stages, volume knob, all that good stuff) and go directly to the Center and Rear speakers. Then the regular stereo Left and Rights are routed back into your Stereo Amp as normal. I used to use a Pioneer unit for this, and I saw a Kenwood one at a thrift store recently as well. They’re still pretty easy to come by and dirt cheap. But once I found a more modern, higher quality amp that handled this type of surround format as well as digital 5.1 and DTS, etc., I upgraded. Love the Sony ES series, so this was perfect for my retro setup.
Additionally, we use a modern Denon receiver and a 7.1 configuration in the living room with all the modern gear, and it was able to accurately decode Dolby Surround from SNES games running on a Super NT over HDMI, so if you just have modern gear and don’t want to hassle with vintage equipment, this is still completely attainable with basically any hardware you probably already have.
And yes! Haha those are definitely Sony speakers I’m using for my rears and center. Nothing amazing like APMs or anything, but they get the job done. The center is from a HTIAB set ~97ish, it’s fine for dialogue, etc. The rears are from a high end late 80s boombox that Sony made, haha. Much too heavy in the midrange for my taste though, to be honest, but I’m not really worried about it… I’m a much bigger fan of the Minimus 11s I’m using for main stereo L&R in that room.
