I have a question specific to the use of the Realistic Quatravox, but with a twist.
Let me first say that I am a novice to many of these concepts, but at least understand them conceptually. Although my question involves audio signals from either a 2-channel system augmented with a Quatravox or similar device, or 4-channel system regardless of how the inner workings produce the "rear channel" signal, the ultimate output of those signals will not be used for my purposes as sound, but as light.
Ever since I was teenager in the 70s, I have always been fascinated with the concept of "seeing" sound through a color or light organ. That fascination has finally found a practical application as I have a side business as a karaoke host and have added that visual to my system. I acquired a matching set of 30" vintage 4-channel (color channels, not sound channels) color organs. Through my ignorance, I over drove them with too hot of an amplified signal. Fortunately, I have found and purchased 4-channel circuits to replace the damaged ones.
Since these new circuit boards will only handle a maximum audio signal up to 100 watts, I decided to purchase a couple of vintage low wattage stereo amplifiers to experiment with. I purchased a Realistic SA-10 and an RCA SA-155. My schedule has not permitted the repair of the color organs or experimenting with the amplifiers.
However, in the meantime, I have also acquired pairs of smaller 3-channel color organs that I am considering converting to 4-channel. That's when the idea struck me that if I used the 30" color organs as "front speakers" and the smaller 3-channel color organs next to the 30s as "rear speakers", would the frequency output of the "rear speaker" signals from a 4-channel audio system be sufficiently "different" from the "front speaker" signals to produce a different lighting effect even if I converted the 3-channel organs to 4-channel?
And as I shopped for vintage 4-channel receivers, I ran across the Quatravox, along with your discussion on this forum.
So my question is, since my ultimate goal is to essentially have 4 audio channels that each produce a unique or nearly unique set of frequencies to drive 4 color organs, am I better off purchasing something like the Panasonic RE-7740/7750, or would either the Realistic SA-10 or RCA SA-155 augmented with a Quatravox serve just as well for this purpose?