Yes, it works, somewhat, especially if the box is in another room. I started with a heavy plywood shipping crate, lined it with 2 layers of carpet, then foam. You need to permanently install the cables in- one for the mic cable, one for a short power cord, and one for a 1/4" speaker cable, in case you've got just a cab in there. I put it 2 rooms away with 2 solid walls between the monster in a box and the drum mics.-Richie