As I mentioned earlier, I built an iso box using my closet for my guitar amp and it works wonders. Lots of ridgid insulation, foam, carpets, pillows and blankets. I can crank that thing very loud and only hear the pick on the strings from 8 feet away. My wife can't even hear it downstairs. When I open the closet door, it sounds like I'm at rehearsal. As an experiment, I plugged one of my bass's into my guitar rig (which uses a closed back cab), and the results were promising. I was able to play without disturbing my neighbours or wife, while getting decent volume and tone through the mics. I think I might go out and find a good 1x12 bass combo and see what I an do. The bottom half of the closet will be the guitar iso box and the top half of the closet (yet to be built) will be the bass iso.