How do loudspeakers play more than one frequency, simultaneously?

Question

I was just wondering how loudspeakers are able to play more than one note at a time, eg. Chords.

Answer 1

Just picture yourself waving a 1khz tuning fork back and forth ten times a second. You're making a 10 hz tone by moving the fork back and forth at the same time your making a 1khz tone by vibrating the fork. If you looked at it on a scope, you'd see a 1khz wave riding on a 10hz wave. The speaker cone does the same thing. The cone vibrates at the higher frequency while it's moving at the lower frequency.

All really complicated sounds can be broken down into mixes of a bunch of different pure sine waves.

Answer 2

All waves are addititive, which means that waves of different frequencies can be combined into one complex wave form.  Sound waves combine in the air into one wave which does not have its own frequency but contains frequency information about all the waves that went into it.  The loudspeaker reproduces this summation wave form, your ears detect it, and it is your brain that does the magic of separating out the different frequencies and recognizing different instruments and voices.

Answer 3

They don't.  They reproduce the sum of all the waveforms in the music at any instant.  Harmonic content and pitches enable the human ear to sort out the instruments in the brain, after the signal is heard.

DK

Answer 4

If you add the sine waves at two different frequencies corresponding to two different pitches, you get an analog signal (note, depends on the phase of the sine waves).  The speaker responds quick enough to reproduce the analog signal in the displacement of the speaker.  The result is two ptiches simultaneously.  Extend this concept to  an infinite distribution of frequencies, and you have a high fidelity speaker.