I have a audio interface + mixer that takes input from my microphone (mic level balanced) and my instrument (line level stereo). I want to build an arduino controlled mute button for those, so that I can use my keyboard to toggle the inputs on and off (can't do that via software because they are mixed beforehand).
The idea is that I can build some sort of device to stay between the inputs and the mixer and is attached to my pc via USB.
I know I can use serial communication for the software, but what kind of relays should I get? I don't want any additional noise in the system.