My local dealer recommended a Velodyne sub, sealed box, servo controlled. So I am on my second one, the DD-12. I really like it and it fills out the bottom end for my Maggie 3.7's. Those are all respected brands you are thinking about. Get one that has room correction that you can override. Then spend time listening and tweaking.
Comparison of various subwoofers for 2 channel audio
I have a 2 channel audio system, and I appreciate how subwoofers have augmented the sound quality of my system (with electrostatic speakers). I currently am using a pair of Martin Logan Balanced Force 212 subwoofers, but I’m thinking about adding more subwoofers for a total of four in order to help balance the low frequency sound waves. I’m considering adding a pair of Rythmik, SVS, or perhaps Velodyne subwoofers to the system. Does anyone have experience with many of those brands, and how well they integrate with electrostatic speakers in a 2 channel system, or perhaps should I just get a second pair custom built with certain specifications?
Thanks.