Simple question, or is it...

An audio signal is purely a varying electrical voltage & current, just that . Nothing more.

Let me start simplifying it:

INDIAN SEE EAGLE OVER RABBIT  (instead of Ohm Law I=E/R)  ;)

Then there is that pesky Square wave...

IF you want to blow a gasket or three, you can do FFT ( I use studio 6 toolbox ) and watch the waveform go by....
Combining three or four sine waves gets messy in a hurry, real music isn’t sine waves.. or simple harmonics- as the late great Roger Modjeski was fond of saying “ what is the 5th harmonic of Beethoven 9th “

for grins, I will put up a screen shot ( Audiogon is so freaking dark ages... ) in my Poverty Bay system pages.. It will be of Steely Dan - The Royal Scam

oh, I am all for childlike wonder but not the ego....