How it measured
The mid and woofer cabinets were both designed to roll off at around 110 Hz.
One advantage of the crossoverless subwoofer design is that while the woofer and midranges wired in parallel create a somewhat low overall 4 ohm impedance, they smooth each other's impedance peaks in the process. Shown here is the rather flat impedance curve and a graph showing relatively small phase angle variations.

The search for better upper bass - the Whampipe
The next development came about from experimentation with a TQWT (tapered quarter wave tube, aka tapered pipe) enclosure designed for Lowther drivers. The lower Q Lowther drivers were not happy in the folded tapered pipe, so on went a new front baffle, and in went the high Q MCM aluminum drivers, and a very smooth upper bass response resulted, extending nicely to about 70 Hz. This particular design won a local "cheap speak" competition between the members of VALVE and the Pacificnorthwest Audio Society. These might be very nice with  B-Glow.

The top end of the internal divider stops about 5" down from the inside of the top panel, and sits centered in the cabinet from front to back. Some Whampipe users like this cabinet without any subwoofer, others prefer the additional bass extension of a sub.