i have a pair of magnavox s-8766 floor standing speakers, and it has this min/max knob on the back of it. I was wondering what the knob is for, i don't really notice any change from it. The speakers are from 1972 or so and i can't find a manual or anything on them, they were my dads but he doesn't know anything about them. Also i'm only using them for 20-80hertz, so i only use the 15" sub in them. If anybody knows what the knob does for these that would be great i'm sure it's on other speakers also. They're air suspension speakers also what does that mean? thanks.