Eminent Technology LFT8B’s reversing woofer polarity

Regarding any perceived brightness in the LFT-8b, the midrange/tweeter x/o (again, symmetrical 1st order filters) is located at 10kHz, well above the brightness range. The LFT-8b allows for three tweeter output settings, but that won't help with brightness. What will help is a superior tube amp (a Music Reference RM-9 MK.2 or RM-200 Mk.2 will work nicely), one reason being the LFT drivers, unlike other magnetic-planars (I'm looking at you, Magnepan) are an easy 11 ohm load, almost purely resistive. The LFT-8b is very insensitive (low-to-mid 80's), but not so much with the woofer run separately. Another factor is toe-in; try the LFT facing straight ahead, or with just a little toe-in. I use diffusion behind mine (Vicoustic 3D), but I have a warm room. For colder rooms, try absorption on that wall (or the side walls) instead.

For those who missed it: the LFT-8b reproduces 180Hz to 10kHz from a pair of LFT drivers, one above the other. Now THAT'S a wide bandwidth driver! Superb coherence and timbral uniformity. As the pianist's hands move up and down the keyboard, every note has the same timbre as every other. My Infinity RS-1b failed THAT test (and the GRR/Rythmik Servo-Feedback Sub is a considerable improvement over that of the RS-1b).

As long as I'm here ;-) :

I'm assuming every LFT-8b owner bought and is using the Sound Anchors stands specific for the speaker. If so, and you intend to keep the ET's for a while, an accessory to consider is the Seismic Pod by Townshend Audio.

While many speakers are candidates for the full Seismic Platform or Podium (I forget which is for loudspeakers), the LFT-8 mounted on the dedicated SA stand is not one of them. The SA stand is a T-shaped outrigger design, and Seismic Pods installed in place of the stock spikes works great. The LFT's center of mass is such that a "C" Pod bolted onto each of the two front legs and a single "D" Pod on the lone rear leg balances perfectly. I had John at Townshend send me Pods made with a bolt hole through the top "cap", which allowed me to bolt the Pods directly onto the bottom surface of three legs (using thread adapters I got from those provided with the IsoAcoustic GAIA footers ;-). The top of the cap is the same diameter as the width of the SA legs, so the pairing looks they were made for each other. Whether the sonic improvement justifies the expenditure I'll leave up to others. I'm not going back to the spikes ;-) . 

thanks Eric - always appreciate your inputs...
jim
@bd

Likewise, all info is much appreciated, good sir -- really key insight shared here.  Also, fun to find a gathering of fellow LFT-ists :).  I'm off to experiment with positioning again, with less toe in this time, as per your suggestion.  Bruce mentions in the manual that they generally sound flat when on-axis with the listener, so I've been doing that by default, but perhaps this is very room and personal taste dependent.

Amplifiers

In  the past 1 1/2 year three tube amps and three pre-amp / phono stage has passed through the ET’s. I  believe with @bdp24 that tubes in the signal chain mitigate brightness. I started with an all tube combo, vintage MFA Luminescence pre + 100 w push pull triode. Needless to say there was no brightness. However, the Luminescence was giving other problems. The preamp chain then  went solid state with Lightspeed Passive Attenuator and a current mode phono stage, creating a more revealing and transparent sound. No brightness, again. I played with a vintage International Projector Corp am 1026 amp for two months. With only 22 w I have come to realize all the talk about how difficult the ET’s are to drive, minimum 100w..etc. is BS. Right now my main amp is from Japan,  Mactone mh-300 b, with output again in the 20’s. Four 300b’s in push pull class A configuration are playing very well with the ET’s. No brightness to report.

Room Placement

My room is 3.3 x 9 M. The ET’s sit 2.8 m from back wall, almost 1/3 into the room, with 40 cm from side wall and quite a bit of toe in.
I am getting the holographic, image specific, and wide soundstage that I was told only box speakers excel in. I didn’t expect it from the ET’s, but thoroughly enjoyable.


Cartridge

Through a recent change in cartridge I did get a glimpse of ET’s brightness with the Audio Tekne MC 6310. Framer described it as more Lyra- like, i.e. analytical, than Koetsu. Well that is a pretty apt. However, adding a damping pad from Origin Live helped greatly.

@ bdp24 Thanks for the Townsend pod information. My only question is whether removing The the sound anchor stand and simply placing the speaker directly on a Townshend speaker base might not be a even better solution?