I saw something I haven't seen before. When disconnecting one channel, both woofers went out. Same thing for the other channel. I looked in the schematic and weird, the two woofers are wired in series! I had to double check to see if I was working on an AMI. (ok, not really) I don't think this thing was ever a "Super Sound". The one midrange sounded like a sick tweeter. I replaced both (the other had been replaced with a crap speaker). Curious about the bad one, I did the "push test" and the cone didn't move. For the hell of it I carefully removed the dust cover and found some glue between the magnet and the voice coil. With a dental tool I broke it loose and got it out. Now it sounds great, most likely the first time since it was manufactured.