why don't middle speakers work?
You are usually spot on WhiteBird but in the case of this 10 speaker "premium sound system" that is incorrect.
This pre-Monsoon/Bose whatever 10 speaker system amp that only powers the rear sail speakers does not switch on and off via the audio inputs. It has a switch signal (PINK wire to the amp) that signals the amp on and off.
This signal also works a power antenna if they are available.
Difficult part is, later model radios/Camaro radios deleted this pin. Therefore if you swap a radio from one of these models into your car, you must do as the OP said. At the back of the radio you need to splice PINK (powered antenna/amp ON) into YELLOW (IGN controlled power).
This unfortunately powers the amp on at all times the ignition is on (not just when the radio is on ala the original PINK wire), but it works fairly well. Also because of the new timing, a speaker pop may be heard at ignition on sometimes.
Spektre
Thanks for pointing that out. I'll make a note for future reference.






