Live Sound Question

[Iglesiasthemaster]

hi-
well i only have one question...
i have gone to many concerts, and when i see the soundman, i see a computer monitor next to him that has these little level bars that move up and down with the music...i know how to do everything else in a live show, but i have no idea what program he is using. i dont know how to get those level meters on there, but i know how to hook up the computer and everything...anyone have any ideas?

[John Sayers]

It's probably a realtime analyser displaying the frequency response from a calibrated mike mounted somewhere near him.
cheers
john