Speaking of the Linkwitz speaker, there is a related product that is uniquely good---the GR Research/Rythmik OB/Dipole Subwoofer. The bass in the Linkwitz is produced by a similar design---two 12" woofers facing in opposite directions and wired in opposite polarity. You may remember an also similar product from the 1980's, the Gradient sub made specifically for the QUAD ESL63. But the Rythmik A370 plate amp contains the patented Direct Servo Feedback circuitry that, in conjunction with the co-designed woofers, produces the cleanest, tightest, most articulate bass you have ever heard. The sub is available only as a DIY kit, which contains the two woofers and amp. Plans for both a W-frame and H-frame into which the woofers are mounted are available on the GR Research website. The OB/Dipole sub produces bass voted "Best Bass At The Show" at multiple RMAF's.
