Hrm. So that sounds like there is a maximum path length difference where the delay from the ES is too much?
Thanks for all the info so far, looking forward to show impressions.
That is a great question. There appears to be universal agreement that <10ms delay for reverberant energy is too little, which is consistent with the late Bob Crump's last CES demo where Bob had the best stereo Sound Lab demo, and the stats were about spaced about 1/3rd the room length's into the room.
The magnitude of the delay is directly related to it's intensity. Speakers with greater quantity of reverberant energy usually employ one particular boundary. Prior architecture employ the front wall for primary reflective boundary whereas we prefer the ceiling for reasons listed earlier.
The taller the ceiling the greater is reverberant delay but also the less is intensity. The ceiling is closer in proximity than the front wall, which favors the ceilng. LCS avoids the downside of a typical dipole or bipole. Such speaker requires greater front wall spacing to increase reverberant delay. But unfortunately that maneuver decreases reverberant energy ration vs. direct energy.
But admittedly, there being no completely free lunch (though LCS gets pretty close), at a certain ceiling height which we frankly have not yet found (estimate 12') the best options appear to be (Duke might disagree):
Making a lightweight moderately sized (about 4 foot square area) "Dispersion Tile" and locating it centered above the Effects Speaker at a vertical height range of 7.5' to 10' (mechanical support from one or any combination of floor, ceiling, sidewall....up around 10' it should be a bit larger, estimate 6-8sf)
or firing the Effects Speaker off the nearby side wall at 65 degree angle ala Toole's recipe
or firing the Effects Speaker off the front wall (like a regular full range bipole ala original Dream Maker or earlier full range Mirage)
In my experience, the first option is well worth the effort. I personally think OC703 with dispersion film is ideal, but for cosmetic reasons I intend to sample a round convex acrylic or plexiglass Dispersion Tile. I envision something clear of course, hanging by transparent ceiling supports, ala Davies Symphony Hall's rectangular tiles in image posted here and at my website. Google "Davis Symphony Hall" images for more interesting ceiling views.
The A-B switch is operational to turn the Effects Speaker on-off. For skeptics thinking the Effects Speaker causes loss of image focus (the dreaded Bose Model 9 effect), put on your most skeptical hat and see for yourself. Bring a solo acoustic instrument recording while an attendant flicks the AB switch. I brought a John Williams guitar CD for this purpose. The recording's focus is diffuse, which tends to favor no Effects Speaker, but still the Effects Speaker improves performance.
