From
this article:
"Within the cabinet, the backwave pressure caused by the rear-facing side of the cone get squeezed through a progressively smaller space as it travels toward the port. This squeezing increases air pressure as the pressure waves move through the cabinet. The pressure waves also pass by a chamber that acts as a Helmholtz Resonator. Helmholtz Resonance is the physical principle behind the phenomena where, when you blow air over the top of a bottle or jug, a distinct sound is produced, and it is how ports produce sound on conventional bass reflex speaker designs. The heightened flow of pressure waves amplify the sound produced by the Helmholtz Resonance in the H-PAS enclosure. Furthermore, the chamber by which the Helmholtz Resonance is created is heavily damped with Dacron, which helps to filter out harmonic distortions that might have developed from previous chambers. By the time the pressure waves exit the port on the H-PAS, they have been increased in amplitude and lowered in frequency, so the system can produce deep bass very efficiently."
I have replaced the word K-BAS with H-PAS, but they are the same thing. Atlantic Technology owns the rights to the word 'H-PAS,' but they don't own the technology.