Simple question, or is it...

The most valuable thing you can do is take a couple of courses in electronics at your local community college. This will lead you to physics etc. It will also help you understand those little bands of color on resistors, how capacitors work (build one?) and what transistors do. A basic understanding will help in many ways. Some colleges even offer classes in sound reinforcement and audio production that will help you understand microphone types, sound processing, recording etc etc.

I would like to add, that it is as far as I can understand it and, of course, I can be wrong (I was wrong once in 1964) :)

If it were you behind these hairdos, I don't know if I can ever forgive you:
https://www.theatlantic.com/photo/2014/05/1964-the-world-50-years-ago/100743/

All the best,
Nonoise

An audio signal is purely a varying electrical voltage & current, just that .  Nothing more.
You can always get into the atomic & particle physics aspects of what makes up electricity itself but nobody really knows :-)  And it does not really matter anyway.