Progress at a crawl, but still forward
I had to take a hiatus from this to finish some software and then to do some construction at the back of the house (a project for my wife and our pets). And the past few days, I have a flu (even got a ride in an ambulance, thought it was a heart attack!), but that lets me sit in a chair with time to write up what progress has happened.
The software work did help this effort, it turns out, as i was able to modify OmniMic so that it gets better windowed response measurement at below the frequency limit of the window. In previous versions, it was a weighted blend of several window lengths into one trace. Now it is more like the MLSSA sliding window (I forget what they call it), in that it always emphasizes the earlier-in-time portions of the impulse response. That gives a better approximation of the responses that you'd get in a reflection-free environment, like outdoors. The curves do look more like what I was seeing last time I was able to make outdoor measurements.
I took two more sets of responses, of each driver (or array) individually, at a variety of offset angles. And the "combined" measurements of pairs (a way of getting relative time domain data precise -- lots written on that elsewhere). I did this with the speaker at two positions relative to the back wall, 12" out and 28" out, for two likely positioning of the speakers. Here are the curves (0, 20, 30, 45, 60, 90 degrees). The 12" from wall seems to be giving me potential for some more directivity extension down to 300ish Hz for way off-axis (not sure why).
edit: looks like the 12" from wall pic is missing the 90 degree curves (which I'm not actually designing for anyway).