Parts Express just sent me the new Ultimax 18" sub for testing. It is a monster that comes in a kit with enclosure and 1200 watt class D amp with DSP. I have not had a chance to do complete testing but the closed miked distortion at 100 dB is the lowest of any low frequency driver I have ever tested. Not surprising because it is 18" and has 22mm Xmax. One of the interesting things I have seen is that if you put in the full range signaleither analog or digital the pass through to the main speakers is not just a straight connection or a simple one capacitor fixed high pass. Rather you can select the crossover point and slope of the high pass with the DSP. I should have the testing and the comparison to two of my 15" sealed box subs done this month. In theory one of these should be the equal of two of my subs in a box considerably smaller than two of my current subs. The photos do not do justice to seeing it in person.
Here is a link to their info:
http://www.parts-express.com/dayton-aud ... --300-7200Tom