The first thing I did was cut out the front and rear
baffles for both enclosures. Now I had a template for
exactly how wide I needed to make the narrow edges
of the 3 curved inner braces, one for the top, one for
the bottom, and one between the woofers. Before I
went further, I cut out the recess and driver holes in
the baffle because I would not be able to after it was
mounted. For the braces, I cut out 6 square pieces
with one dimension that matched the depth I needed.
Using the front and rear baffles, I marked on opposite
sides of one square piece where the curved edge
starts and ends. I drew a 1'-8" radius curve along
both sides starting and ending on those marks. I had
to cut an 8" diameter hole in two of these braces for
the middle section which was done using the router and circle jig. I cut the sides about 2 inches larger
than I needed in both directions so I had enough
play. Then I cut 7/8" deep grooves lengthwise in each
piece 1" apart. These were glued on and trimmed
with the router. This enclosure is approximately 2.1
cubic feet after displacement, and is tuned to 27 Hz,
with an F3 roll off at around 37.
The MTM cabinets are much simpler, and are
basically a 2-way bookshelf speaker with my version
of a time aligned baffle. These are also ported due
to the large cabinet size. The box volume is a hair
under .5 cubic feet, with a tuning of 52 Hz and an
F3 of 55 Hz. Although, this doesn't matter much
because of the bandpass filter on the mids that get
cut off around 450 Hz.