Martin Logan Balanced Force 210

This sub is the most amazing sounding sub I have ever heard, the sound matches perfectly with my main speakers ESL11a. It’s a little pricy but worth every penny, you cannot find a better subwoofer to blend with Martin Logan speakers. It’s a must have part of any electrostatic panel speaker. I wish the color match to my ESL11a was better, both are dark cherry and two totally different shades, but the finish is pristine and a very nice component to showcase with other ML speakers, looks defiantly make this sub have the WOW factor.

Seamless extension to the lowest octave of human hearing
I used to work in the field of engineering acoustics, including some work in speaker evaluation using impulse functions. When I saw that Martin Logan was selling some subwoofers that were capable of custom tuning using what appeared to be a familiar technique, I had to have one. The PBK space averaged transfer function that they appear to be using just begged to come home with me. So I bought the BalancedForce 210 and ordered the PBK accessory to be delivered later. I thought this set up would have really excellent "play value" for someone with my interests. It was my plan to mate this subwoofer to my Theos main speakers in a two channel system. I noted that Martin Logan has a custom function that can be downloaded to effect this pairing, and I intend to install the proper file later. I am writing this note today because, following the instructions in the BalancedForce 210's owner's manual, I was able to pair the subwoofer with the Theos beautifully, and without resorting to downloading any files or using the PBK accessory. I will look forward to doing these future tweaks, but for now I am wrapped up in very pleasant listening. The Theos are quite good, have a +/- 3 dB limit at about 43 Hz. The 210 allows you to pick up the next lower octave of program content. Many two channel sources have very little, or even no acoustic content in this lowest audible octave, but for many recordings, the lowest audible octave adds richness and reality to things like large drums, very low bass notes from organs, electric basses, acoustic basses, synthesizers, organs, and the like. I've played through several cds today, and I think there were noticable improvements that I could hear in every case. Most of the musical program material that I selected was chosen for my love of the music. But eventually I had to try some recordings that present special challenges to reproduction equipment. The most notable of these was Paula Cole's "This Fire." I have NEVER before heard a believable playback of the first cut, Tiger. There are a couple of bass segments on this cut that will cause every other speaker, including the unaugmented Theos, to crash and burn. The Theos augmented by the 210 breezed through this cut, including all of the absurd infrasonic bits that accompany the audible low bass notes. I like this subwoofer better than I thought I would. Its low frequency cut off limit is 30 Hz, so this allows it to "get out of the way" of the Theos very effectively, and they mate up exceedingly well. The stock settings of 90 degrees for phase, 0 for the 25 Hz boost/cut setting, 4 for the level setting, and 30 for the low frequency limit setting seem to be hard to improve on. I look forward to being proven wrong when I get around to downloading the Theos matching file, and going through the PBK set up. I would buy this component again without reservations.