How to drive a driver (how does the waveform look?)

[janfure]

Hi;

I am a beginner, about to make a simple amplifier for a subwoofer. It is simple enough to copy the circuit from the applications example, but one thing puzzles me slightly: I have been unable to find any specification for how a speaker (technically driver) should be driven, does a proper audio signal allways consist of an electrical waveform where the voltage on the positive lead is higher than the negative (ground) lead? From the amplifier circuits I have seen, this appears to be the case, but I don't want to just assume and end up building a circuit which clips the bottom off every waveform, by connecting the negative lead to -Vcc.

If somebody can explain or point me to a reference, I would be greateful.

Jan