Man I love your reviews thanks! and it's a relief to know there are others that hear the difference. I will comment on what that is below.
I am glad you tried the on wall approach, I had a narrow room and it was a shock to set the various speakers I had over the years out doors and be lost in the image, move them back indoors and it's mostly gone.
When I had a pair of early prototypes in that room, I found they were better but one day on a whim I tried against the wall and WOW it was sort of like being outside again.
The speakers can do this because the origin is at the rear of enclosure and so the arc of the wave front is very nearly the same as the enclosure walls and horn wall angle. Remember these radiate a portion of a sphere.
Unlike normal speakers, one can place two of them side by side and not hear any seam listening to music. That same thing allows a physical boundary to be used instead (like a wall or floor).
I know exactly what you mean about being transported, feeling the emotion. One of the things that happened to me as these progressed over the years is I went back and listened to old recordings and discovered endless details I never heard or didn't remember. As weird as this sounds, the two first Led Zeplin albums were like listening to new recordings of a familiar event.
Yes, the object of these is to do a good sized venue with one per side. Subs can be added but are not needed, for example at Northwestern university football stadium, they used two of these for all of the pa system, music / voice / special effects for 46,000 people I think it was. Four, with subs are at BYU stadium for a very large place.
One question most people ask is doesn't this fry the people up close?.
Well it is a point source, most people think of a point source as an omni directional speaker which that is an example. A point source can also have directivity, have a very different energy profile depending on angle. If one has a speaker with constant directivty, that energy is confined into a given angle over a span of frequency.
A perfect constant directivity speaker can confine all the energy into the design angle from DC to ultrasound but very useful things can be done well short of theoretical endpoint.
Picture a speaker with a single radiation lobe, draw an imaginary line around that lobe and say that is the same SPL anywhere on that line (an equal loudness balloon).
Imagine the speaker is placed over the stage up in the air and the center of the lobe is aimed at the heads in the back row.
Now, the loudest part is pointed at the rear where the distance is greatest. As you move closer, you are moving off progressively axis and since the energy the speaker radiates falls off as you move off axis. There is a combination of lobe shape, height and audience depth where the SPL is nearly constant from front row to back and in extreme cases, the Shaded amplitude approach can be used to tailor the lobe shape.
Assuming I can find a picture and link it, the speakers that look like a bird house are synergy horns with amplitude shading, the result is a + - 1 dB SPL variation over the seating area.
Picture #2 http://www.danleysoundlabs.com/danleyport.asp?ID=61
The idea of using the lobe of a single horn is an ancient one, I heard about it at a Synaudcon seminar in the 80's and it was old / obsolete then.
The problem was a single horn wasn't always powerful enough and wasn't full range or constant directivity. When you add a second source or make it a multiway, the single lobe is destroyed where ever more than one source is radiating the same frequency.
What I mean is how sound acts depends on the spacing relative to the wavelength. Take two subwoofers, place them close together, they add coherently, radiate equally in all directions. If you reverse the signal to one, you very nearly cancel all the sound (the principal of active sound cancelation).
Now, when your spacing exceeds the fuzzy 1 / 4 to 1 /3 wavelength between sources, now one has entered a new condition, an interference pattern. For example two sources 1 / 2 wavelength apart produces a figure 8 polar pattern. Now, if one reverses the drive to one of the sources, the sound isn't canceled out as in coherent addition but the interference pattern moves, the figure 8 is rotated 90 degrees. The farther apart they are, the more lobes and nulls the interference pattern has, the farther from coherent addition one is.
By using conditions where the sources add coherently to each other and other ranges at crossover within the horn, the horn remains to set the constant directivity radiation pattern, a single lobe over a broad band driven by the equivalent of a single crossoverless source.
Not producing an interference pattern was a requirement I thought for larger scale sound because one wants the sound spectrum to be the same everywhere, but the effect smaller scale is interesting and I believe the why of why with a voice, playing through one speaker, they are much harder to hear the loudspeakers depth location / why they can produce such a strong stereo image.
Interestingly, a real hifi speaker company has recently discovered you can hear the source shape as well. While they are not CD, do not preserve waveshape and cannot go as loud, the KEF blade system addresses the audibility of the source shape.
FOH's comment on the video is interesting too.
When Mike and I began this adventure we performed generation loss tests with loudspeakers. You see it's not all about measurements, just one would be a fool to ignore what they can tell you. In the generation loss test, Mike would use a Digital recorder and good measurement mic to record a loudspeaker (up in the air away from reflections). A music track would be played and recorded then the mic signal played back through the speaker and recorded again. Each generation becomes more of an exaggeration of what is wrong, a perfect system being able to undergo unlimited generations.
In reality, most speakers sounded bad on gen 1* or awful at 2, few were ok at 3 and our best sounded funky at 4 bad at 5.
* partly on account of the entirely different way we hear from two points in 3d while a mic is one point.
Anyway, a weird part of not having source interference and getting close to a single broad band source in time and space is that there is less generation loss even one way like a video that includes the sound.
Well i have put off a task long enough, back to work.
Danley Sound Labs
"Sit down and listen, its about sound, it's why you got into audio"