Fabricated from scratch...not just a mod.Bruce,
The ported section is open into the doghouse. According to djk, this can give you almost flat to 30hz. With a standard LS, you can open up the TOP of the doghouse, and enclose the back (where the crossovers reside) and put ports out the back. Same volume increase. Or you can remove the bottom cover, and stack teh LS onto a ported box to accomplish the same thing.