This is my coding for handling serial spectrum input for sending music via the USB to an arduino to control a visualization on your LED strip (or matrix if you do some additional programming)
https://github.com/jbud/FastLED-Serial-Music-Arduino/tree/master
You make interesting things! I always look for music-to-light devices and software, so I am glad to see your new one! 
Btw, since you did this, maybe you interested in another Arduino “color organ”, with direct audio input and FHT: “YALO” (it is not mine, i just very like it. Author nickname is nicoyn):
I mean, maybe you find something interesting in code for your future ideas.
Thanks, I’ll look it over.
I plan on writing my own program or plugin that outputs the audio via serial. May take me a while since it’s outside of my experience range. For now, the solution I mention in the readme should work fine
This is exactly what I’ve been looking to do with my LED strip\ home built pc. Hopefully it’s achievable by me!