My basic concept for the cabinet construction was to use 6" nominal inner diameter PVC. The tubular cabinet design dictated the use of a woofer that would have a mounting cutout of 6" or smaller. Due to the fact that I wouldn't be able to create a substantial internal volume with this approach, I started modeling woofers to see what could be achieved in terms of low-end with the limited volume available.

Dayton DA175-8: I was surprised to learn that the Dayton DA175-8 would be able to achieve an F3 of less than 50 Hz when loaded in a 6" diameter by 20" long PVC tube enclosure. This driver also exhibits low distortion and a relatively fl at frequency response up to 1800 Hz. In order to decrease distortion and also raise sensitivity and power handling, I decided to use two woofers wired in parallel. The color I had chosen for the cabinets contrasted nicely with these very attractive aluminum-cone drivers, so their pleasing appearance was a bonus.

Dayton RS28A-4: Needing a tweeter with roughly 91dB sensitivity and the ability to acoustically crossover below 2 kHz (due to the center-to-center distance between the PVC "modules"), the RS28A-4 was a natural selection. This driver also exhibits low distortion in the targeted high frequency pass band, and exhibits a fl at frequency response. As a side benefit, the look of the driver (with the dome being hidden behind its protective screen) complemented the aesthetics of the overall cabinet design.