I am just about to put my tempest sonotube together. I have plugs to go in the tube with a cherry top for the top of the sub for looks. I also made a cherry base to go on the bottom. It turned out to be just a ring really 18 inch tube at 15 inch driver. I plan on mounting the driver in the plug. The the ring goes on the plug around the outside just for looks. This means that the driver is not flush mounted, it is actually sunk in about 3/4" in the bottom. With the have any bad affect of the sound? This thought never even crossed my mind when to comes to subs. Is this a bad idea? My other option is to leave off the bottom cherry piece, it just won't look as good.