The drivers are designed by Atlantic and have been customized to have a fairly high resonance. (About 65 HZ with a very robust x-max). This is counterintuitive in the world of conventional speaker design. The real heavy lifting with H-PAS is executed in the cabinet design. There is a labyrinth of ducts and chambers that capture the back wave of the driver as it starts naturally rolling off. The cabinet has elements of acoustic suspension, bass reflex, inverted horn, and transmission line and there is also a bass trap to strip the unwanted second third and fourth order harmonics. These cascaded design elements pressurize and physically boost the decreasing level of the back wave.

As a result the bass response increase exactly matches the speaker’s bass response roll off until it exits the vent in what we describe as a “controlled explosion” of low frequency energy. An H-PAS design can achieve flat frequency response down to 30-40 Hz below the resonance point of the drivers. The result is substantial dynamic range, very low distortion, and of course deep bass response out of moderate size drivers.

Conventional thinking with audiophile speaker designs is to specify very low resonance drivers. This approach taxes power, and dynamic range for the sake of achieving deep bass response. With H-PAS the cabinet does the heavy lifting. Therefore, higher resonance drivers develop the control back wave and the cabinet takes over from there. The drivers don’t have to move as far and due to this one characteristic there is an order of magnitude less distortion and very extended bass response

This approach reminds me of the Broadway show "Wicked" where everything you believed about "The Wizard of Oz" is upside down.

I don’t blame anyone for being skeptical because H-PAS challenges everything we know about speakers. We had tremendous fun at this show just watching the expressions on the faces of all the visitors to our demo room. When we played the speakers someone likened it to the “Susan Boyle moment”