A nice post from Montres on what, exactly, you’re hearing in the tick and tock of a mechanical watch:

Some of the sounds occur almost simultaneously although different escapements have distinct characteristic resonances. Some of these sounds are very short and others (i.e. when things are sliding) are drawn out. The loudest sound is the dropping action, when the escape wheel tooth drops off of one pallet stones and hits the next pallet stone. That’s the “tick” & “tock” heard when you hold a watch to your ear.

I highly recommend reading the entire post, and check out the image link as well. I’m wondering if I can make my own watch regulator by writing some code to read the sound off a microphone and fit it to the expected trace… hmm.

Update: From the links on the Montres page, a better image of the components of the sound:

Looks like the software is do-able, this guy wants $300 for a complete solution. Cool.