Duke, how would you describe differences between LCS placement options:
1. LCS touching front wall
2. LCS right behind wide baffle speakers (Zephrin style)
What I'm thinking is that 2nd option might be better fot mid/high frequencies but worse for low/mid.
(wide baffle casts bigger "shadow" for higher freq but lower freq wrap aroud it and interfere with direct sound)
While 1st option is more even for both hi/low freq but also requires a lot of distance behind main speakers because LCS is not so well hidden behind an obstacle.
What's your take on this subject. Which is better Zephrin style or regular LCS at front wall?
Somewhere I have images where I sited Zephrin 46 rear panel about 1" from the front wall. Frankly, the overall presentation did not change much from my normal distance, IIRC 76" (HWD 7-7" x 16-7" x 25-6"). The main difference is shorter stage depth, but even that was not severely handicapped. The rest of it was otherwise surprisingly similar.
One really cool use for the Space Gens alone: you all probably noticed, during parties, for "atmosphere," a main high end system is generally distracting, especially during peaks, it's impossible to get a good level because on peaks it just overpowers conversation. Stuff a couple SGs behind a sofa or where ever they are not seen, and line of sight output is damped. You'll get almost the same level throughout the space, and it's shockingly good quality, and no problem w/peaks overpowering conversation.
My system is dual use, retractable perforated screen. I recently watched several minutes of a movie when I finally realized the front main speakers were off because I forgot to switch on the tube amp (separate amps employed). The quality of the sound is remarkably smooth, coherent, and highly musical and enjoyable.
I'd wager if you heard them for party use you'd want a pair just for this application. Ceiling speakers could never accomplish the same thing. Anyone standing nearby would suffer from proximity effect. (Interestingly, AVS online forum editors said this same item caused them to prefer up-firing Atmos over ceiilng mounted in Dolby's demo at CEDIA 2014.)
Zephrin 46 owners could always disconnect the main-front speakers for the same party application.
I happen to have for sale LCS 2.0 (about one third smaller than original LCS) in case owner of original Jazz Modules is interested (single amp) or any speaker w/separate amp. These are HWD 13 x 17 x 20, $1740/pr ($2900/pr SRP), like new full warranty, walnut, re-veneer extra cost, four 5.25" + horn, high 30 Hz bass cutoff. $100 Parts Express 45W Tripath amp w/volume sounded pretty darn good...this speaker is 8 Ohm fixed level, flat impedance above the bass range, 6 Ohm minimum, as usual for AK, very easy to drive even w/tubes.
Space Generator treatments: I found ceiling treatments in my short 91" ceiling to be of little to no help. Conversely, the closer is the SG to side and/or front wall, a 2" rigid fiberglass panel w/dispersive surface helps.