I signed up for the contest as well, as the technology is pretty intriguing.
My guess as to the "sound-steering" technology is that for each of the five signal channels, a variable time delay is applied to the signal, with the delay being slightly different for each of the speaker elements. For example, the Front Left channel signal is sent to each speaker element, but with a "continuously" varying time delay as you move across the face of the speaker array. This serves to "beam" the FL signal over to the left side of the room. The same approach is applied to the other four channels, with different delay algorithsm to beam the channels in the appropriate direction. Thus, at this point, if there are 42 speaker elements, you actually have 42 slightly time-varied versions of each of the five original channels (210 total signal streams). The five signals for each speaker element are then combined, and fed to the individual amp for each speaker element.
(My reasons for believing this is the technical approach are two statements made by Yamaha about the product: 1) there is a separate amp circuit for each of the 42 speaker elements, and 2) each speaker element is putting out a portion of the sound for each of the 5 original channels.)
The approach is very similar to the use of phased antenna arrays in microwave radio systems, which require line-of-sight transmission, and therefore (in some applications) you want to be able to steer the antenna.
Obviously there is an awful lot of DSP power required to do this, but that fits with Yamaha's "core competencies" (to use an overworked phrase), and explains why they were the ones who came out with this product, versus a primarily-speakers company.
The downside is that all of the channels except for the center channel need to rely to some extent on reflected sound (i.e, the sound is beam-steered to side and rear walls, depending on which channel it is). So, if you put one of these outdoors, I would think that the soundstage would collapse, and in a very large room it is probably hard to get a good effect. My guess is that the set-up analysis processs is very complicated, in order to be able to deal with a broad range of room dimensions and shapes, in terms of tailoring the delay algorithms to deal with the room reflections that are required for the 5-channel effect.
