Transmission Line Subwoofer

Here is a transmission line subwoofer I built:

Components: a 4.5" Labtech driver (salvaged), a Dayton SA25 amp, 5' of 4" schedule 40 PVC pipe, some 3/4" plywood, polyester batting, tightbond 3 wood glue, Locktite construction adhesive, silicone caulk, and a can of blue 'granite' spraypaint.

Links:

Steve's T-line subwoofers
http://www.t-linespeakers.org/
Tubular TL Subwoofer
http://www.quarter-wave.com/