Re: SH-50 array eq.
The Sh50 has an interesting "beginning".
Toms origional "tuning" for the Sh50 was very different than it is now. Origionally the plan was to have a pair of cabinets produce a flat response. Since the cabinets start to lose pattern control around 300-350Hz (ish) the mids and highs had a higher sensitivity than they do now.
Since the cabinets would be losing pattern conrol (and it was assumed that generally a pair of cabinets would provide a decent coverage pattern (100x50)) the low end would combine well-as the drivers were close enough together.
I figured that the Sh50 would be used by itself quite a bit (as is done in home stereo and home theatre applications), and proposed that we "tame down the mids and highs" so that a sinlge cabinet had a flat response. So that is what we did.
Now this idea is both good and bad. It is great for the single cabinet applications (of which there are quite a few being used) and bad for a pair of SH50 applications-of which there are quite a few being used.
The problem when you use a pair is simply to much midbass. So you have to throw that away. I usually start by putting a great big "hole" in the eq about 1 oct wide and about 6-10dB deep (how deep really depends on how close the cabinets are to a boundary) around 225Hz. Sometimes I throw a few other notches around the "big one" to even it out a bit.
Your rolloff is basically doing the same sort of thing-getting rid of the midbass.
This gets rid of the mid bass "gak" that just gets in the way. Below 100hz we all like the additional bass-so I usually don't throw that away. Depending on the system (how it is used with subs and so forth-subs on an aux or crossover over to the mains) I high pass around 45Hz-100Hz.
For what it is worth-when the SH46 was made-we used Tom's origional approach. Figuring that the SH46 would only be used in multiples (unless used singly as a delay-in which the low freq would not be needed as much), the low end would sum (below the horns pattern control)-and figuring that the Sh46 would be used in applications that were typically louder than the SH50, the mids and highs were allowed to "run more free".
So when multiples were put together-the response would be a lot flatter than a single cabinet-without having to "throw away" some of the energy.
In every design-there are a lot of decisions/choices that are made-depending on the particular intended use of the cabinet. Sometimes- how the cabinets get used is very different than what was origionally intended-so some other "compensation" needs to be made for that application.
I hope that that helps somewhat.
