Since we are using a woofer that has a very high Q, we are in a situation where there is no "optimum" enclosure per se'. High Q woofers should be used in sealed enclosures, and the larger the enclosure, the lower the system Q will be. But, it will never drop below the Q of the driver in free air, so at some point we have to draw the line on the enclosure volume due to practical size limits. In this case, I decided to use a 2.0 cu. ft internal volume for the woofer, which translates into a 16" tall, 24" wide, and 12" deep cabinet. Even fully stuffed, this enclosure still leaves the system Q very high, so a larger enclosure could be used if desired. The midrange and tweeter are both fully sealed, so they can simply be dropped into cutouts in the baffle.

I want to point out that the horizontal orientation of the speaker is not critical to the design. This speaker could just as easily be oriented vertically with the drivers aligned down the center of the speaker. As a true garage speaker, the horizontal orientation worked better for my application. But, a vertical orientation would place the acoustic centers of the drivers closer together, and may yield slightly better integration between the three.