Actually jwt, a pair of the OB/Dipole Sub kits is $1500 shipped, and a pair of the H-Frame flat packs is $600 I believe (I got in on the first few sets made at an introductory price). So it’s about $2100 for a pair of the OB/Dipole Subs and really good H-Frames, CNC cut from 1.5" thick MDF! All that’s left is finishing the frames, paint or veneer. Each sub contains a pair of 12" Servo-Feedback controlled woofers facing in opposite directions (they don’t have to be, but doing so creates a couple of benefits), and the Rythmik plate amp with a dipole cancellation compensation shelf to counterbalance the acoustic roll-off inherent in dipole speakers. The amp is available in a couple of different configurations, one being balanced/XLR in and out. One band PEQ is provided, as are high pass and low pass frequency and slope adjustments, three levels of electrical damping, and, most importantly, a 0-15ms Phase Control. Do NOT buy a sub without continuously variable phase adjustment. A 0/180 switch is worthless, and that’s exactly what most subs have. This sub is made specifically for music reproduction, being optimized for sound QUALITY, gladly sacrificing maximum sound quantity to get it. The output of a pair of the OB/Dipole subs is about equal to a single sealed Rythmik. Are you willing to give up 3dB in output to obtain the OB/Dipole sound quality? I was.
In addition to the lack of sealed or ported enclosure resonances, an OB/Dipole sub creates cleaner bass also because it excites only the room mode of the dimension it’s front and back faces. If you fire it down the length of your room, the room modes of the width of the room are NOT engaged---the null created to each side of the sub prevents it. So elegant!
The sub is absolutely and without question the best sub in the world for any and all planar loudspeakers. Not only does it’s Open Baffle design and construction provide the same advantages (and liabilities) as does the non-box design of planar speakers, but it’s dipole acoustical properties and behavior matches that of planars, unlike ANY box sub in the world. The acoustical output of dipoles drops off at only half the rate of boxed speakers; if you balance your speakers and box subs at one listening distance, that balance is different at a different listening distance, and in all other parts of the room. Not so with the OB/Dipole Sub, as it shares with OB and dipole speakers (which is what planars are, of course) the exact same acoustic SPL drop-off with distance rate. Again, elegant!
And I haven’t even brought up the benefits of the Rythmik Direct Servo-Feedback system, designed and patented by Rythmik owner Brian Ding. Not just another servo design, but a new, better one. You think the servo-feedback woofers in the Infinity IRS were clean? Wait until you hear this sub! It’s sound has been described as "stops on a dime". It's the only sub I've found that isn't embarrassed by my Magneplanar Tympani T-IV bass panels. NO overhang, no boom, no bloat. The Rythmik Audio/GR Research OB/Dipole Sub---the only Servo-Feedback OB/Dipole Subwoofer in the world!
