system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:If the coil on a speaker cone can only vibrate at one frequency at a time, how come I can hear two notes simultaneously?

It's something that I've wondered about sound waves in general, but this is the best way I could think of wording it. If I play a song through a single speaker cone, how come I can distinctly hear each instrument?
gpt
A speaker does not vibrate at a single frequency.  You know this for sure because of the observation in your post - a musical "A" is a different frequency than a "C".  It does produce a single waveform.

Think of throwing a rock into water.  Now throw another rock right after it.  The waves you see represent the combination of both those rocks.  You see a single wave patten the result of both, it is the result of the "frequency" of both waves.  One waveform, multiple frequencies.  

The speaker is capable of creating the complex waveform that is made of multiple underlying frequencies.