Mike, it isn't entirely clear to me from what angle you're appoaching this. Although I rather like Bren's suggestion, I suppose that you're really thinking about clipping. A square wave of the same amplitude as a sine wave at the same frequency requires the square root of 2(i.e. 1.414)times as much voltage, and since power is proportional to the square of the voltage(i.e. P=V(squared)/R), this amounts to twice the power going into the speaker voice coil on a fully-clipped or square wave signal. Since the voice coil has to absorb twice the power, but it doesn't move any farther on the clipped or square wave to help it in cooling, it can overheat and fail if it can't dissipate the exta power over the time period involved. So, I suppose that answer is that no speaker is "square-wave proof", but the greater its power handling capacity, the greater its ability to play square waves at high level or to handle clipping without permanent damage.
Edited by JohnK (03/02/04 05:40 PM)
Enjoy the music, not the equipment.