Well, the boxes were due today and the kids have a lot of work to do.
For those students that read this thread, you must use at least 3/4" material, any span of more than 8" needs a brace, and gaps need to be filled with a urethane glue (Elmer's or Gorilla Glue work). Your box must be designed from the Theil/Small parameters, not a generalized table ( 6" woofer = 600-800 in^3 or 8" woofer = 800-1600 in^3). Those tables are too vague and have too much error. Also, mount the drivers in the narrow side of the box, not the widest. Tweeters and midrange drivers need to be mounted flush with the front baffle. Some of the boxes can be fixed (thin walls can be laminated to turn 1/2" material into 1" material), gaps can be filled, braces can be added, but incorrect volumes probably need to be redone. Eggcrate foam just doesn't do much. Multi layers of 8lb. carpet padding with a layer of vinyl next to the cabinet, mounted in the interior, is pretty good for DIY deadening material. Sealed boxes need a fiber fill (pillow stuffing or fiberglass).
MDF is the preferred material compared to particle board, or regular plywood. If you use plywood, use at least a marine grade, and baltic birch is better still. Pine 1"X 10" type boxes will be hard to dampen, regardless what you do to them.
TO THE REST OF THE FORUM, what other tidbits should we advise? The kids had to have boxes ready for inspection today and received their woofers, mids, and tweeters. Everything is to be mounted and a prelim Xover schematic is due at the end of April.
