Re: working of speaker and audio s/m
sreejith,
Yes, it is. To convince yourself that this is true, sketch out a waveform that consists of the sum of a fundamental and a third harmonic. The result will be a very crude approximation to a square wave, with "wiggles" in what would be the flat portions of the square wave. The speaker simply follows this waveform, which, in effect, means that it is vibrating at two different frequencies simultaneously.
Regards,
Kral