>The sealed sub absorbs the backwave of the open baffle driver. Not really a new idea.
Not exactly.
When you add a monopole and a dipole together you get a cardioid with 4.8dB directivity (versus 0dB for a monopole) which interacts better with room modes than the monopole.
If the engineers have done their job right, their sub-woofer should become monopolar at low frequencies (you're not gaining anything below the room's fundamental resonance, and a dipole's excursion has an additional doubling for each lower octave you play) so you're not loosing low end output as you would with a dipole (that also has 4.8dB of directivity)
