Dahlquist DQ-1LP crossover owners

I used a modded DQ-LP1 for better than two decades and wish I hadn’t sold it. I’m not certain if a 5dB boost at 20Hz is enough for what you need, but the DQ-LP1 does offer that, via it’s EQ setting. Mentioned under, "controls and adjustments" on page 3 of the manual. If you need the entire Bass level increased, you could adjust in favor of the bottom, via the Level settings, which offer 15dB of gain.  Manual here: (https://sites.google.com/site/mpbarney/home/dahlquist-dq-lp1)

Good thought, rodman, but what f456gt is in need of is not a set boost of 5dB at 20Hz (or any other single frequency), but rather a 6dB/octave slope to counteract the dipole cancellation of his subs, adjustable for different x/o frequencies. THAT is exactly what the dipole "shelving" circuit in the Rythmik plate amp provides. The only separate x/o I know of that provides that is the special version of the First Watt B4, made especially for open baffle speakers, which also of course exhibit dipole cancellation with decreasing frequency.

Got it now.  Kinda like a Bose 901 EQ does(at both ends of the spectrum), but- not at as high an order.   Then again: I've seen Tympani Bass panels, used with different mains(ie: QRS) and a DQ-LP1, with great results.   WHEW(that's been a few decades)!   

Thanks chaps for the info about the Dahlquist.

I was planning to buy one to use with a pair of Gradient W-63 OB clones using two 12" Peerless 830500 drivers per side, it is very similar to the prototype built by Sigfried Linkwitz.

The problem with the crossover is that the sub needs a 6dB/octave boost because it is a dipole and I would guess most off-the-shelf solutions don't offer this.

The subs will be connected to my pair of QUAD ESL-63. I would also like to use my spare QUAD 405-2 for the subs.

I considered the Rythmik OB kit using two GR SW12-8FR and one A370PEQ Servo amplifier) but the dual driver configuration costs $1,200.
I am retired, with a fixed income and the price is a little bit stiff.

The price of the Gradient project would cost $252 for the drivers, plus the price for a crossover. I will build the enclosure myself, I have plenty of baltic plywood left from other projects.

Best regards,

Horacio