I have been looking for a few years to find a sub that would be a match with my Electrostatic speakers. I had a pair of Quads ESL 63's rebuilt and they of course lack the deepest of bass and I wanted to add the foundation missing to my audio system. I purchased a few, some worked better than other prices ranged from $900.00 to $1,600 none work to the point where I forgot they were in the system nor did they have the speed to blend with the Quads fully. I got my Audio Advisor magazine and I saw the Depth i for sale, after thinking it over and knowing Martin Logan makes wonderful electrostatic speakers I said if anyone can make a sub to match it will be ML. I spoke with a rep at Audio Advisor and he was great with answer my questions I decided to order one for my system. Received the sub within a week, read the manual followed the directions, make a few adjustments and all I can say is this, this is one of the best purchases I've made, everything a sub should do this unit does, clean, tight, fast, goes deep down with no fat bass or bloat, not only would this sub work with Electrostatics speakers but any cone speaker I've owned in the past would have been better with this sub. I am enjoying my system more, hearing the little things better, the imaging is better and more open sounding, and like eletrostatics speakers the distortion is as low from the highs down to the bottom end. Right now no cone driver speaker as ever been able to reproduce such a clean and distortion free sound, with no glar, or forwardness. What electrostatics to great is still there, now I have the lower mid-bass and lower in the same high quality of reproduction as the rest of my speaker system. Just a wonderful product for any system. I should add solid built quality to match the sound. This is one highend sub woofer without having to cost $5,000 and up.