@yyzsantabarbara , I, like aniwolfe, toe-in the LFT-8b’s a lot, aiming them right at the listening position. That positioning is normal to me, as my main speakers for years were the original Quad ESL’s. Severe toe-in minimizes the amount of side wall reflections, which is important in a small room. You want all sounds except those from the front of the speaker reaching your ears delayed in time (relative to the direct sound) 10ms or more. That is the amount of time our ear/brain mechanism requires for two sounds to be perceived as separate events. Anything less than 10ms, and the delayed sound is perceived as a smearing of the direct sound, rather than ambiance.
The 3’ that aniwolfe recommends as the minimum distance the ET’s should be from the wall behind them is the common wisdom for all dipole speakers, not just the ET’s. 5’ is even better, if the room allows it. The reason for that is the 10ms figure; with a planar positioned 5’ from the wall behind it, the speaker’s rear wave takes 5ms to reach that wall (sound travels at approximately 1’ per ms) and be reflected off it, another 5ms to arrive back at the speaker. That rear/reflected sound is now delayed in time 10ms behind the same signal from the front of the speaker. Your ears hear the direct sound from the front of the ET’s, and then the rear wave 10ms later---mission accomplished! This is an over-simplification, as when the panels are not parallel to the wall behind them the rear wave will be reflected off first the sidewall behind the speaker, then the rear wall, then perhaps the opposite side wall, finally reaching the listening position. Some people like diffusion behind dipole/planar speakers, others absorption. A bright room will benefit from absorption, a dull one with diffusion.
The LS50 is good for small rooms because of it’s coaxial driver; separate midrange drivers and tweeters need a certain amount of distance to "congeal" by the time their sound reaches the listener, but the coax driver in the LS50 doesn’t. One benefit of the unusually wide bandwidth of the ET’s LFT midrange driver (180Hz to 10kHz!) is the same as that of a coax---one driver and no crossover for the entire midrange (and more). Yes, a coax is really two drivers, but those drivers in many ways behave as one. The LFT-8b is 5’ tall, but only 13" wide. It doesn’t overpower a small room the way larger planars do (none more so than the 3-panel Magneplanar Tympani, which is 4’ wide!). For very small rooms, ET offers the LFT-16a, a monitor-size speaker containing the LFT driver, a ribbon tweeter, and dynamic woofer.
One criticism of the original LFT-8 was it’s high frequency output, which was somewhat lower than many other speakers. The LFT has a 3-position tweeter hookup provision, which allows the tweeter’s output level to be selected. Some listeners thought that even at the highest setting, the LFT-8’s tweeter output was too low. Bruce Thigpen made a change to his ribbon tweeter, it’s location of the speaker’s baffle, and the speaker’s x/o. The change resulted in a new model designation, the LFT-8a. The only other change to the LFT in it’s entire history was to a better low frequency driver---an 8" dynamic woofer in a sealed enclosure. That resulted in the only other model designation change to the speaker, to the current LFT-8b.
The LFT-8b has a nominal impedance of 8 ohms, but the LFT driver/ribbon tweeter combo presents an 11 ohm load to the power amp. The speaker has dual binding posts, one for the panels (LFT driver and ribbon tweeter), the other for the woofer. The panel’s 11 ohm load makes it much more tube-friendly than the other magnetic-planar loudspeaker---the Magneplanar, of course. The LFT-8b is not "ruthlessly revealing" (a euphemism for bright/forward), so can be paired with a good solid state amp. Because of the dual binding posts, if one chooses to do so the speaker can be run with a tube amp on the m/t panel, a solid state on the woofer. That makes possible the use of a pair of moderately-powered amps, but if one wants to use a single amp, a good hundred watter should be sufficient for all but the largest rooms. The same can not be said of Maggies (I’ve owned four pair of them, including the Tympani-IVa’s I currently own), which can use as much power as you throw at them.
