low-pass filter
I toyed with the idea of measuring the output of the DD-12 with the internal crossover turned off to see what the response of the Velodyne DD series subwoofer of that size was, up into the lower and middle midrange. But without any way of gauging distortion, I don't think it would be worth the effort. Although the response is flat to close to 200 Hz, if the SMS-1 video output is any indication, I suppose there could be some analogy between the DD series with respect to the high bass/lower midrange and the successor DD+ series with respect to the middle base. The enormous voice coil on the DD15+ is apparently responsible for the upward sloping response, even below 100 Hz, with descending frequency.
With that in mind, I thought it would be better to be a little more conventional and set the low-pass at 150 Hz, 12dB/oct for the surround channels on both the DD-12 and DD-15.
If I'm unhappy with the result and a cello does not sound like a cello, with the low harmonics plainly evident, then I figure I could always recycle the Axiom M3ti's I had before and bandpass them with a 3-way crossover. The idea would be to recreate the high bass "bump" of the bass reflex design that's missing from the acoustic suspension. Two speakers, two 6.5" woofers, one ported, one not. However, I only have one available channel of amplification available, so that would be yet another hurdle to climb.
