So, over the week I discovered something kinda cool.
Because of the way music is produced these days, subtracting
the lead vocal is often as easy as subtracting one channel from the other.
This is great if you can’t get a real karaoke version of the song,
or you want to learn the harmonies.
Software has been doing this for years, but with a simple rewiring
of a cable, you can do it in hardware.
All you gotta do is connect both channels of an external speaker
Across the two channels of a sound output. thats right. you just hoo the ground of the speaker to one channel, and l and r to the other.
this easily finds the difference in channels.
Also an interesting demo of how all amps are differentiall
because they all at the very least are ground referenced!
Better writeup at my website