Thanks guys. The sub is already isolated to the extent that it is raised up on floor spikes, so its points of contact are minimal. Would an additional isolation pad serve to reduce the compounded bass in some parts of the room, and counter the effects of cancellation in other parts? I won't know until I try it, I guess.

Within the limitations of having a home theatre in a multi-purpose room, I've got it tuned-up pretty good. Is it perfect? Of course not. Is it worth worrying about the last little bit? Perhaps only if you're descending into that maddening hell of audio perfectionism that is the bane of every audio nut, like the one I fear I'm becoming (I'm passing out the grains of salt right now...).

Aside from the furniture, our living room has little else that would help modify it acoustically. The mini blinds are probably as reflective as the plaster walls. The little bit of reading I've done so far indicates that acoustic treatments help minimize the impact of the acoustical properties of the room itself, so that your're hearing your speakers more, and the room, less.

Now, if I can incorporate this into a painting/decorating project...

To boldly stumble where others would pause thoughtfully,

Best Regards.