Hi kcarlile,
A slight correction: the audio signal from your amplifier or receiver's output that drives your loudspeakers is an AC signal, not DC. The push-pull action of a speaker driver--a cycle of compression where the cone pushes outward and compresses the air molecules, then reverses itself, moving in the opposite direction, creating a rarefaction (an expansion) only works with an alternating signal. It is the alternating signal through the voice coil within the fixed magnetic poles of the speaker magnet that make the speaker driver what it is--a reciprocating electro-magnetic motor.
DC is the last thing you want to enter a loudspeaker. That's exactly what happens when an amplifier goes into overload and "clips" off the tops and bottoms of the AC audio signal, sending a DC signal into the driver voice coils, causing them to melt, fuse and burn out.
Regards,
