The Mini incorporates custom-designed drivers and a special low crossover point. PSB’s goal has been to create a smooth, natural sound with surprising bass for such a small speaker. Some very careful work went into the Mini's enclosure design, which feature five-layer construction and has no visible seams whatsoever. The bottom section of the enclosure features a cleverly design plinth, which provides a recessed pocket for speaker binding posts and sleek, concealed attachment points for optional PSB wall-mount brackets or speaker stands. As you can see from the photos that accompany this review, the sidewalls of the Mini cabinets are curved along the sides, top panel, and front baffle, for what designer Paul Barton often describes as an "organic" shape.
The SubSeries 1, in turn, is designed to offer significant output down to the deep bass range. PSB has created a driver and cabinet combination with a -3 dB point of 36 Hz, which is actually pretty low if your room will support it. The SubSeries 1 provides level, low pass filter cutoff and phase controls, and it can be driven by line level, LFE or high-level (speaker) connections.