Magic Music Visuals

How do users typically get Magic to respond to standard output, like a song playing on your computer through the speakers? My Soundflower Aggregrate devices include standard output but it doesn't respond. I do have it working with my internal mic now, there is a little dropdown in the upper right of...

I just installed the demo and all I see is a black screen. I think it's supposed to be reading input from the microphone, but the input sources are both pointing at soundflower channels.

Anybody know what I need to do to see the demo work with Soundflower installed?