Actually the soup cans added some much needed dampening in the basement, and also provided some diffusion to break up all those flat walls. I'm keeping the soup cans in the listening room, just moving them out from under the speakers where they can do more good.

We don't need no steenkin' Pebbles.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8