Observations:
1. Listening in a much smaller ENCLOSED room (maybe 10 x 12 ft with a high 12 ft ceiling), the ripole performed better than in my previous experiments in larger, more open spaces. I used an inexpensive pair sony bookshelf speakers (normally my home theater rears) for mains sound. I brought the ripoles in about 60 Hz in this test.
2. The ripole was basically done at 30 Hz, with woofers flapping about like a fish out of water, with little sound to show for it. Above 30 Hz, the bass was clean and even with maybe a few room modes. When I run the measurement tests, I'll use an actual amplifier - as opposed to a plate amp, to be sure I'm not dealing with any plate amp boosts / high pass bass cut etc . I can use my minidspor a PC equalizer later on to smooth out the room modes.
3. We rigged a crude 6th order bandpass by placing the ripole in a cardboard box. This brought up the bass about 50 - 60 Hz but was more uneven overall
4. We rigged up a crude 4th order bandpass by sealing the rear section of the ripole against the carpet. This had roughly the same effect as 3, but at different frequencies.
5. Based on our experiments, I feel that to have a successful ripole system, a good amount of swept displacement and / or a small room is needed. This 2 driver ripole with modest subwoofers performed halfway respectable in a small room but would be hopeless in our main living area.
6. At this point, I might build another identical ripole after I fix my saw, .. A pair of 2 driver ripoles with these drivers should work "OK" in a small room . Ripole "merits" apart, I would not have considered this approach if I didn't have so many of these woofers lying about (literally, at this point).
Measurements, and DSP correction to follow, in subsequent posts.
Here's a pic of the 6th order Frankenstein