Another recepie is to use 3/4" or 1" high density fiberglass with layers of MDF. (fiberglass accoustical ceiling tiles ata home center will work) Cut the tiles 20 x 20 and MDF 24 x 24. Stack up layers of this with 3 or 4 layers each. Have the Home depot guy cut the MDF for you and I think you can manage to cut a tile with a utility knife. Cost you 20 bucks, a trip to HOme Depot and 10 minutes assembly time.

Havnt tried this one either. My turntable is still up in Canada