I've had my AI Contra combo for about a year and a half, and for the most part I'm very satisfied with it, with nothing but compliments from other musicians for the tone and volume/size ratio. I do, however, notice a great deal of variance in the tone depending upon the surface that the speaker is firing down on. Being somewhat averse to knob-twiddling, this is a minor but growing annoyance. The best tone, I notice, is when the surface is highly reflective, such as linoleum or hardwood. The worst tone was last Saturday, when I played an outdoor gig on a slatted wood deck (probably sounded great if you were lying under the deck). No gigs on shag carpet as of yet. I've mulled over a possible solution; schlepping around a hunk of particle board, melamine, or some other such material to make the surface consistent from gig to gig. Any other Contra owners have this problem or hit upon a more inventive solution?