Hi Uncle John,
You sort of went in a different direction than I anticipated following the first post.
When the L1 was first introduced it was highly promoted as a system designed for one person. When used in that manner, even with several onstage, it is easy to determine who is playing what and where it is coming from. The Model II and the L1s project in a pretty flat beam the height of the speaker array. The Compact is a curved array similar to, but much smaller than a 502a which serves to change the dispersion from a flat beam to one that is angled up and down slightly to provide some addition vertical dispersion.
The F1 flexible array give the user control over the vertical dispersion to match the seating or listening arrangement of the audience.
The MA12 series of speakers came about during the 10 years of L1 development, and were the first of the 12 speaker line arrays to be brought to the market. I recall seeing a pair at a Bose dealer on tri-pod stands when I was purchasing a 402 II system just before the release of the Classic.
The fact that they are still on the market and have been improved and redesigned tells us they are popular, but I don't recall ever seeing a pair, or even one, being used as a portable system outside of that dealer setup.
The M12 series have a much larger cabinet which allows them to produce lower frequencies than the L1 column, but that lower frequency range is not part of the spectrum that is steerable, and with only one column the steerable cutoff is 500 Hz. That means for music reproduction one would need a sub to supplement the bottom end if the steerable feature was critical to coverage.
Over the years I have played on a lot of different stages and have always been able to direct the L1 "beam" to my audience. In most cases a simple short 2X4 under the front or back will accomplish enough angle to get the audience within the confines of the vertical dispersion.
I recall very early, when this forum first started, we talked about the possibility of a jointed array column (a knee and an ankle) to give the user more control over the dispersion, but I think most of that was based on us, the early adopters, and Bose getting used to a brand new speaker design that had properties the engineers were still figuring out and the users didn't understand at all.
While I could see the steerable feature something that might find value in the Model II or Model 1s, I don't think I would sacrifice the portability of either for that feature and use the MSA12X in its place.
O..