1) Eminence markets a unit called D-fend that is put between amp and speaker that controls the voltage output, peak and average. It can be (must be) set for the specific parameters of the speakers used, but once set is virtually bulletproof.
2) Looks like the 2 box output at 62 Hz is simply a typo (I have done the same more than once..), most of your other readings average around a +6 dB per doubling of cabinets and power as is normal, though from 2-4 is generally a bit less, perhaps due to amplifier current limiting. As Ivan points out, your test conditions are responsible for some of the frequency response you measured, the dip at 60 Hz is larger than the usual Lab Sub response deviation.
As far as how many cabinets you use, that should simply be determined by the SPL level you require for the gig. Every room (or partial room like your deck measurements) requires it's own EQ to deal with room modes and proximity to boundaries, so the relatively small differences in EQ required between 1 and 4 cabinets are just another variation to deal with.
1) Yes, I've been looking for user reports on the d-fend...doesn't seem to have sold too well and seems to be sold out everywhere except Amazon Home and Garden Shop...really !
Should I give it a try?
2) Yes thanks, typo...should have been 94.3
3) As you and Ivan point out, boundaries and reflections make the kind of measurements I'm trying perilous.... but I did get lucky and figure out the crazy dip at 63 hz for 1 and 2 labs as per yesterday's chart...
I knew the dip couldn't be a reflection cancellation because the suckout was everywhere I walked around and listened to. I am using steady sine waves with time to roam around and listen.
(the freakin reflections are what made me give up trying to learn Smaart indoors about 10 years ago lol )
It turns out, there must be a passive radiator suckout from the adjoining Labs that aren't being driven.
The middle two in my bank of 4 get sucked out at 63hz, either singly or as a pair when the others aren't driven.
With subs numbered 1-4 left to right, yesterday I chose (by bad luck
#2 as typical for one sub, and 2 & 3 together as typical for 2 subs.
Today I remeasured pairs and quickly found the only 2 sub combo that would dip at 63hz was 2 & 3.
So I removed 1 and 4 from the bank, from physical proximity, and bingo...no dip for the pair, or singly!
Here's the results of today's test .. #4 is closest to house, hence the gradual increase in levels with tests that lean towards the higher combos.
Sorry for the false alarm on the subs...the novice learns...
Oh, and John...waiting to hear from A&H....