I'm very curious about Franck Tchang's "SugarCubes". Small rosewood blocks (about the size of a sugarcube) with special channels (aka holes) drilled into them, that are used in a special grid formation to treat room resonances. For, as he says, "you do not fight a problem. You spread it around, minimize and blend it in to reduce its overall impact on the room's sonic fingerprint." His HeartSong racks (want one), which use related ideas, are to die for. And you might have to to get one, if the wood is unavailable, because orders stop at that point. I'm gonna throw out a free tweak idea based on the Sugarcubes, if anyone wants to try it. I am putting it on the list to get around to it eventually, but I don't have the time or inclination to get into that right now. If you have an audio rack that uses (removable) wood shelving, bore a small diameter hole into the center of the shelf. See if that improves things.