The original plans are on the single driver web site at the link below. I made my most recent pipes (with the Fostex drivers) about 1" deeper but otherwise the same. Using a front-mounted speaker baffle will enable you to adapt different drivers if you decide to do that later. Also, if you use two joined pieces of meaterial (instead of a single full length piece) for the backs it's possible to build these from a single 4X8 piece of material.