Steve Guttenberg finally reviews the Eminent Technology LFT-8b loudspeaker.

So Ric (@ricevs), you’re no longer a fan of the GR Research/Rythmik Audio OB/Dipole Sub? That too can be used in place of the stock LFT-8b woofer.

The 2-woofer version of the OB Sub kit is available from Rythmik for $999, and from GR Research with the required OB H-frame (in flat pack form) for $1660. Both prices for one sub, two required of course.

If you can build your own H-frame (or the smaller W-frame), a pair of the OB Sub kits will run you $1998, about $400 more than the pair of LFT-8c woofers. The difference between the two is the Rythmik/GRR is an open baffle version of a dipole sub---with two 12" woofers, and the LFT-8c has a front-firing 8" woofer and a rear-firing 6.5"---in a sealed enclosure. Both are powered, the LFT providing DSP not included in the OB SUB. But the Rythmik plate amp does provide all the controls necessary to mate the OB Sub with the LFT-8b planar panel.

Turns out that the problem may have been the Khozmo passive preamp… I switched to my Precision Fidelity C7 tube pre and output seem to be the same in both channels. Will be doing some measuring as soon as I can borrow a 0hm meter from a friend-:)

2 years ago Ron at New Record Day stated the Spatial M3 Sapphires with their passive bass woofs were "faster" than Danny’s servos......he compared them several times. He talks about this starting at 28 minutes in.

https://www.youtube.com/watch?v=iFQKGaxfIJk

The servo subs are great.....but they are not state of the art. The guy at GT Audio was using the servo subs and is now using Acoustic Elegance woofers in his H-frames.

https://www.gtaudioworks.com/

The servo subs also cannot play that high and have limited tunability. Using a xover/amp you can set the xover anywhere you like with the AE woofs and equalize to your hearts content and get rid of all bass nodes.

Please read this review on the Kryon speaker using AE woofs.....the guy said it was the best bass he ever heard in his room. Of course, you need to make a serious baffle and brace it well. Kryon uses the AE woofs in all their open baffle designs including the monster one without any baffles.

https://6moons.com/audioreviews2/kyron/1.html

https://kyronaudio.com.au/gaia.html

Joe Cohen of the Lotus Group designed the two Granada speakers shown here (using the same AE woofs).....way over 12 years ago. You can search for reviews.....they were loved. Don’t know if any were sold.

https://www.lotusgroupusa.com/granada-loudspeaker.html

@ricevs: Yeah Ric, in one of his YouTube videos Danny Richie speaks about New Record Day Ron having found the Sapphire to produce "faster" bass than the Rythmik/GRR OB Sub (just for the record, Ron's opinion carries little weight with me). Danny contacted Ron to find out what the heck was going on, as in Danny's opinion that was most unlikely.

Turns out Ron was running the Rythmik/GRR OB Sub with its' Extension Filter Damping control set to "Low". With the 3-position Damping control knob set to "Hi" (Q= 0.7 Bessel filter), or even "Mid" (Q= 1.07 Chebyshev filter),  the OB Sub produces considerably tighter bass, at the expense of reduced output. 

When I used the servo subs I found the bass much better with the fuse bypassed in the amp and the binding posts all bypassed on the drivers.

You might want to call the guy at GT Audioworks and ask him why he changed from the servo woofs to the AE drivers.......certainly wasn't to save money.

What I would like is for Bruce to sell the new 90db neo drivers mounted in the new panel by themselves with just wire hanging down (the mid/tweeter thang shown in the 18LS proto).  Then make an external super passive xover for the panels and then run two AE drivers on an open baffle next to it running with full digital electronic crossover and eq and solid state bass......I bet that would be killer......and a lot less expensive than the 18LS thing.

Another cheap alternative would be to get a minidsp crossover and 4 channels of amps.......make an open baffle speaker and bi-amp it with two AE 12 inchers on the bottom and 4 series parallel GRS 8 inch planar drivers ($60 each from Parts Express) mounted above the woofs.....all on the same baffle.  The crossover would be used to equalize and time align.....Crossover, wires, woofer amp, drivers (AE woofers are over $500 each delivered!) and wood would be less than $4500. ......you just add a source.  This would be killer.  You would use your existing amp on the panels and buy a cheap class D amp for the woofs.  I am pretty sure the ET drivers (especially the new neo ones) would be better......but, this would be way cool.  You could use the GRS drivers passively but they might need some eqing.....so some crossover design knowledge might be needed.  If you use the inexpensive digital xover....then anyone can get great sound in an hour.  The series parallel GRS drivers would be around 96db sensitive.....so even low powered tubes could drive them.....cross over set at around 400 hz.  Of course, you could use just one AE driver, two cheaper 12 inchers, one $60 planar.....etc. to infinity.

https://www.parts-express.com/GRS-PT6825-8-8-Planar-Mid-Tweeter-8-Ohm-272-126?quantity=1

SO MANY POSSIBILITIES!!!!!  Life is grand!  Love is in the air.....spring has sprung.....wishing you all joy and beauty.