I haven't had a chance to use the orbital sander just yet, but table saw has already proven to be worth its weight in gold. When it come to making repeatable cuts, nothing beats a table saw, and this made short work of the cuts that I had to do. Thankfully when I went to Home Depot, a helpful employee cut a couple 15" panels out of the full 4'x8' piece on the panel saw, which also significantly cut down on my work.
Before making any cuts I did a few checks to make sure the saw was properly aligned. I measured from one of the teeth on the blade to the fence, then rotated the blade until the tooth was at the back of the blade and measured again.
Since the measurement was the same, the blade was well aligned with the fence, and I got started on making the cuts.
There was a small setback, since I found that I had misjudged the sizes of my material, and I'm currently short one 19 1/2" x 14 1/2" side pieces. I'll get some more MDF when I get the chance, and cut that last piece.
Once everything was cut out I clamped up the sides and the top and bottom for one cabinet, leaving a bit to hang over on the top and bottom so they could be trimmed flush with a router later.
While the glue was setting up, I got started making the template for cutting out the recess for the waveguide. I followed the instructions in this post on flush mounting irregularly shaped drivers and started by making the larger router base. In the picture below is the circle jig I made for my router, including the incorrectly measured hole for the cutout.
Without thinking, I measured to the far end of the bit, which resulted in an exactly 6 1/4" diameter hole, and a 1/2" smaller cutout, so I remeasured and finally cut out the 6 1/4" disk I would go on to use as the larger router base.
Once the larger router base was cut, I put the original base back on. Next I screwed the waveguide into the MDF (this time 1/4" thick) and traced around it with the router to make the template.
With the angle on the edge of the waveguide, the router base ended up tracing a little too close and made the template slightly too small, so I'm going to cut out a slightly smaller custom router base which will make the final cutout larger. Tomorrow I should be able to finish up the front baffle and hopefully close up one of the boxes.