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

@bdp24 I convert everything to 24/192 and RIAA correct the phono stage in the digital realm. I use digital crossovers, EQ and room correction to amazing effect. You have no idea what you are missing. But, I understand the purist approach. I drive an old 911. I have own new ones and do not like them, too darn refined. 

@ieales , You are not imagining anything. The bass of the Tymps is flabby at best. In total I think the 20.7 is a better loudspeaker. It still has less than optimal bass.

You are 90% of the way there with your speakers. IMHO your next move should be to disconnect the woofers in the speakers and build four 10 or 12" passive  subwoofers and space them evenly out on the front wall flanking the ETs. I would drive them with two amps and keep the channels separate, not mono. The crossover point I believe is 180 Hz. If you use a steeper slope (10th order) with your digital crossover you can safely push the crossover point down to 160 Hz. Time align everything and your bass energy will simulate a live performance. I use my old JC1s for subwoofer duty but I use to use a pair of QSC  commercial AB amps to great effect. Much less expensive. Dayton and Parts Express make incredible subwoofer kits at great prices. You can build for 12" subs for less than the cost of some commercial 12" units. Their drivers are absolutely top notch. I use 8 of their 12" Reference HO DVC drivers in my new subs. Each enclosure gets two drivers. I will be publishing the photo history of their construction on Imgur shortly.

@mijostyn Back in the mid to late 80's I had Tympani 4's. The earlier version where the 3 panels did not separate.

I converted my garage with advice from the Winey's to have one wall built on a slight angle to eliminate parallel walls. I then installed 2 layers of 1/2" drywall that were glued and screwed to the studs with glue between the layers along with 3 sets of headers between each stud location. The headers were about 20", 45", and 72" approximately above the concrete carpeted floor.

The amplifier for the bass panels was a Levinson ML-3 with dedicated 20 amp circuits for each of my 3 amps I was using at the time.

The bass performance was rock solid that it's equal I have never heard.

Describing the bass as flabby leads me to believe you have not heard the true bass potential of this speaker.

I recorded my Gretsch drumset (with a 26" bass drum) with a pair of small capsule condenser mics plugged straight into a Revox A77 reel-to-reel, using that recording to scrutinize and evaluate the sound of loudspeakers. For years the Magnepan Tympani bass panels came closest to replicating the live sound of that bass drum of all loudspeakers I auditioned: freedom from bloat (caused by driver "overhang"), percussive impact (i.e. attack), tonal timbre, texture, etc. For the sound of my Paiste 602 cymbals, it was ESL and ribbon tweeters.

The sound of a bass drum (even a 26" one) is more mid-bass than deep-bass, but those Tympani bass panels were very, very good at mid-bass. The sound of open baffle/dipole woofers is the closest dynamic driver equivalent to planar bass I’ve heard, the sound of the Rythmik servo-feedback subs second. For context, I own a pair of transmission-line loaded KEF B139 woofers (used by David Wilson as mid-bass drivers in his original WAMM loudspeaker), and owned Infinity RS-1b loudspeakers in the past, which had woofer towers containing six 8" servo-feedback controlled woofers.

@ricevs What you are describing for the 8c ' Extreme' is certainly interesting. I already have the 8c; however, I would be interested in knowing if Bruce would be willing, at a minimum, to provide a neodymium mid range panel replacement. Please keep us posted. 

What will be the benefits of the neodymium upgrade? The lighter weight of the neo is moot as the moving part is the mylar in a planar system.  Will the more power magnetic field generated translate into more clarity and detail?

@bdp24 It certainly would be informative to listen to your set up vs 8c. The main difference being DSP vs electronic x-over. But as @mijostyn mentioned you are a purist on this issue. While I don't always agree with @mijostyn, especially his adamant refusal to accept the merits of under slung tonearm ( he he ), digital signal conversion, even on analog source, is something I have come to accept. I don't understand why it works, but......

@ieales The timeline of your 8b upgrade around 2021-2022 coincided with Bruce's upgrade work on the 8c. Did he mentioned anything to you about it? It seems such a coincidence!

Oh, and I recorded the sound of my two year-old son and then-wife’s voices, using those recordings to evaluate loudspeaker freedom from vowel coloration (thank you JGH ;-), and midrange transparency. A brutally-revealing test! That led me to---of course---the Quad ESL.