I have a Denon receiver playing music from my record player, I can use the Samsung TV remote to control the volume but only when the TV is on. With this setup I see the Denon receiver logo on the TV while the record player is playing sweet tunes. I'd like to have a music visualizer app playing in sync with the audio from the receiver.
ProjectM is what you are looking for. Not sure it can be set up for an external mic though (usb)