The Goal: The client was looking to achieve ~20Hz – 80Hz audible performance from a relatively compact enclosure in the trunk of a 1991 Honda Accord.
The Design: In this particular model, consistent efficiency (at the headrest) throughout the target bandwidth was best maintained with an off-axis firing bass-reflex design and rather tight back-wave control.
The Build: Here’s a good depiction of what it takes to achieve a strong bond: Very consistent pressure, and plenty of it!
For air flow linearity at high volume levels, the narrow vent design required a bit of expansion at the mouth. For this, a 1″ radius flare was routed along the outer corner of the compression chamber:
45 deg. slants along both the inner and outer bend of the waveguide help maintain the proper cross-sectional area. The end of the waveguide terminates at a slightly expanded throat with a 45 deg. slant in the corner, and 0.375″ radius bevels routed away from the end of the waveguide panel:
Once the enclosure is fully assembled into a solid “block” of MDF, it is ready to have it’s features “chiseled” out of it:
As a finishing touch a 0.625″ deep inset was cut into the 1.5″ thick double-stacked face baffle, with a 0.375″ radius flare along it’s outer edge. All the corners along the width of the enclosure are beveled with a 0.5″ radius round-over to keep the edges from snagging while preserving a sharp overall look: