A further thought about the BBAM. It allows one 6.5" driver to act as a time and phase coherent point source across a wide range from 2kHz down to 30Hz. This(together with the superb silk dome Dynaudio Esotar tweeter) is part of the charm of the design. For a time I tried a Velodyne DD-15 rolled in at 35Hz. It vastly increased scale and impact, but I could never get the timing quite right, and eventually learned to live with the VSMs sub-less.
@tubegroover My VSM and BBAM are both highly modified with premium caps, resistors, cabinet modifications, and a Paul Hynes SR7 power supply for the BBAM. I wouldn't want to be without the modified BBAM. The stock NiCad battery supply seriously limited performance of the BBAM.