Originally Posted by dazzdax
Hi all, does any of you have experience with mating electrostatic speakers and Rhytmik subwoofers?
Do you have some recommendations regarding placement of the subwoofers, subwoofer level and crossover setting (cut off frequency and slope)?
Is it possible to get tight and "controlled" bass that matches the electrostatic midrange and treble?
Which ESL's do you own, Chris? There are ESL users on this forum who are very happy with sealed Rythmik subs in use with their speakers. There is another way to go with dipole speakers; Brian's collaborator at GR Research, Danny Richie, has a version of his 12" paper-cone Servo-woofer optimized for Open Baffle (OB) use. You use two of the woofers in a frame, facing in opposite directions and in opposing polarity. The sub's output is therefore similar, at certain frequencies, to that of panel speakers, dipole.
There is another speaker designer who is a proponent of OB subs by the name of Linkwitz. You may have heard of him! He designed, and builds and sells speakers with OB subs built in. They are very similar to the GR/Rythmik OB sub, but without Danny and Brian's excellent woofer and the Rythmik Servo circuitry and plate amp. The GR Research sub system is not offered as a finished product, but as a DIY package with two woofers and one Rythmik Servo plate amp (it is listed on the Rythmik DIY product page). Double that if you want stereo subs (a good idea if you're crossing-over above 80Hz or so). You can build the frame (plans for which are on the GR Research site), or have them built for you. There is also a woodworker/cabinet maker who is offering flat-pack (knock down, ready for assembly and finishing) H-frames on the GR Research AudioCircle forum. It makes a perfect stand for all models of Quad ESL's (in fact, there is a company in Europe---Gradient---who offered OB subs specifically for the Quad 63 in the 70's-80's, which were in fact designed to serve as stands for the 63's), which is how I use my W-frame variant of the H with Quad 57's.
In my opinion, the OB Servo-Sub is THE way to go with dipole speakers. Fans of OB subs cite their lack of box resonances as one reason for their very clean (some say lean, until they become accustomed to the OB sound. It is absolutely astonishing with standup bass and the lower registers of pianos) bass quality, but also their lack of room "loading", dissimilar from sealed subs. There is a penalty you pay for the sound quality, however: reduced output as you descend in frequency. Only you can decide if the sound quality an OB provides is worth the reduced output it costs. Or, you can go nuts and use the OB's down to, say, 40Hz, and then sealed subs below. It's only money!