Log in or register to post comments DIY Projects pklinkhamer Mon, 09/01/2008 - 16:52 The box is 3/4" mdf wrapped in real 1" thick wood veneer. Internally lined, and sits on floor spikes. After a good breakin, it sounds great and plays very loud and deep. Select ratingGive Custom Passive Sub Box 1/5Give Custom Passive Sub Box 2/5Give Custom Passive Sub Box 3/5Give Custom Passive Sub Box 4/5Give Custom Passive Sub Box 5/5 Average: 3 (6 votes)