This one's for all you PA-amplifier-powered people. I read somewhere that one could get more power from a two-channel amplifier by hooking up the first channel of the amplifier to the first speaker normally, but then invert both the input polarity and output polarity of the second channel so it is operating out of phase with the first one. The result is that there is a lot more current available. Perhaps this could be applied to dual-voice-coil drivers like the Tumult and others for a more powerful, impactful sound that doesn't run out of gas as easily. This only works with certain kinds of amps, that have a separate power supply for the positive and negative voltage. This way, where one supply would be overtaxed at a time and the other would be idling, current is drawn from both power supplies on each inward and outward stroke. I wonder how it would work with dual voice coil drivers driven by the two channels of a PA amp?