http://line6.com/m9/ - Gannin Arnold shows you how to solo over guitar loops using a different tone with M9 Stompbox Modeler.
M9 Stompbox Modeler has a wide variety of vintage and modern tones. Over 100 stompbox effects. Create up to 24 pedal board scenes. Included is a 28-second looper that provides the most fun you can have without getting arrested. It delivers extended, in-the-moment sound-on-sound looping and unlimited sonic possibilities.