Originally Posted by
JimC
I think you'll find the tales about DC are pretty much a myth. This is an AC signal like any other. It's not DC at all, even if the signal, by the time it got through the wiring, any crossover and anything else, were still a pure square wave. What it is is a very high energy signal, and any sufficiently high energy signal will burn out the coil. Most likely what causes the confusion is that a nominal 1KW amp will deliver 1KW as an undistorted sine wave, but getting on for double that if you actually drove it into the unlistenable level of distortion a pure square wave would imply. Real DC does have an extra risk, since the voice coil isn't moving, which deprives it of cooling, but an AC square wave has the cone moving just as much as any other signal, and provides the same air movement and cooling.
For all the myths around square waves, we should remember they're one of the main building blocks of additive synthesis, and there's no risk at all in reproducing them provided that the drivers aren't overloaded.