I'm designing and building a subwoofer with the Adire Audio PR-15 15" passive radiator. I've already built one, designing it using Unibox, but the results were not what the software predicted.

The active driver’s 2” peak-to-peak travel is exceptional excursion for a 12” woofer, but the passive radiator’s 4” peak-to-peak travel is extraordinary. The throw of the passive radiators is so long ...

A passive radiator looks like a driver because it has a diaphragm, but unlike a “real” driver, it doesn’t have a voice coil or driving mechanism. This also means that it doesn’t have connection ...