Pairing Planar Speakers With A Subwoofer (Eminent Technology)

The perceived "speed" of a sub is greatly influenced by the room, where in the room the sub(s) is(are) positioned, not merely the mass of the sub’s driver. "I am afraid the speed of the sub or lack thereof cannot be improved by positioning". No, but it certainly can be made worse by poor positioning! By the way, do you know the mass of the Rythmik and REL woofers? How about that of the GR Research 12" paper-coned woofer? How about the gauss figure of those woofers motors (magnets), without which the cone's mass figure is irrelevant?

Regarding the distance a planar is from the wall behind it, that distance effects not only depth and imaging, but also frequency response via comb filtering. The back wave of the planar reflects off the rear wall, meets the front wave, causing frequency-related cancellation and reinforcement.

Hey @grigorianvlad, is that a Yorkie? Great little dogs!

As an owner of Maggies, ET LFT-8b’s, and Quad ESL’s, I have to ask you: is where your panels are located in the pics where you listened to them at? The common wisdom is that planars need to be at an absolute minimum 3’ from the wall behind them, but I consider 5’ a better number.

And as an owner of a number of subs (GR Research/Rythmik, Rythmik, HSU, KEF B139’s in transmissionline enclosures, former Infinity RS-1b owner), I have to ask: did you try the F25 in different locations in your room? Corners are the absolute worst place for subs, if sound quality rather than quantity is the priority.

Damn that F25 is big!

Mitch, the F25 is indeed an excellent sub, and will work quite well with the ET LFT-8b. I have a pair of F15HP’s (DIY version---I made my own 4cu.ft. enclosures), which have a single 15 woofer to the F25’s dual 15’s. Same sq, but the F25 has greater maximum spl. Both the F15 and F25 are being used successfully with magnetic-planar (mostly Magneplanars), ESL, and ribbon loudspeakers.

For reference, I am a former owner of Infinity RS-1b’s, and I consider the ET LFT-8b a superior loudspeaker. However, the LFT-8’s single 8" woofer is no match for the RS-1b’s servo-feedback woofer column, with it’s 6-8" woofers. Any of the Rythmik servo-feedback subs will be a great partner for the LFT-8 (used in place of the ET’s woofer), creating a very full-range, high-output hybrid. But for the ultimate version of such a design, there is an even better sub for use with dipole speakers, one also available from Rythmik’s Brian Ding, in a collaborative effort with Danny Richie of GR Research: their Servo-Feedback OB/Dipole Subwoofer, the only such design in the world! You can read about it on the GR Research AudioCircle Forum---there is too much to it for me to post here.

$1500 for a pair of the sub kits (a pair of 12" woofers with the Rythmik servo-feedback plate amp per side), another $500 for a pair of the H-frames they are installed in. $2500 for the ET LFT-8b’s, $2000 for the subs (plus the cost to finish the H-frames)---$4500 for performance far exceeding what you expect at that price point imo. The ultimate magnetic-planar/dynamic sub hybrid! Imagine---a dipole planar speaker with a dipole/OB sub---a perfect pairing!! I can say all this not just hypothetically and from theory, but from practice---this hybrid is my creation! As far as I know, I am the only ET LFT-8b/OB-Dipole Sub owner in the world. But the OB/Dipole Sub s being used with lots of other high-performance speakers, mostly ribbons. Ric Schultz of EVS has designed and is selling such a design, using the Rythmik/GR Research OB/Dipole Sub.