[Arran]

Probably for whatever any two people were willing to pay, if anything, for an as is unit. I believe that there were some car stereos of the era that had quad sound, FoMoCo offered it in some of their cars, I'm not too sure about G.M or Chrysler though. Quadraphonic sound was an interesting idea, but in the end it really amounted to no more then a fad, the number of quad cartridges that I have run across I can count on one hand so not many people were buying them obviously. I have one and what it has is right and left channels like a normal stereo tape, but then it has a pair of right and left rear channels which was just the music with no lyrics, so basically it's an 8 track with half the programing of a regular 8 track. Like AM stereo it was one of those things where nobody got around to establishing an industry made standard.
Regards
Arran