Raynist, when you get a chance can you take a max spl sweep? I am curious to see compression characteristics between a standard 80-90db sweep and a max spl sweep. I also would like to see the output them beasts are generating. A basic 80-90db sweep that you posted is great for getting a idea of the subs frequency response, but it does not tell the whole story.
For example here are a couple graphs I took a while back when I only had dual XV15's
Top graph is a standard sweep and the bottom is max spl.
Aside from the peak(i took these measurements with no eq'ing), you can see the top graph is pretty much flat down to 15hz. when I run the max spl sweep I start to see some compression below 25hz, but its still maintains +/-3.5db from 15-25hz and 45-85hz.
Max output was 113.5db @ 15hz, 132db @ 32hz, 120.5db @60hz.
Avg. max output from 15-60hz = 122db. Which is dam close to what my spl meter would show. Actually with source content I could get another 2-3db(125db) of additional output since test tone material is much more demanding.
I since added a third XV15 to knock down the peak which it did. I plan on taking some new measurements soon when I get a chance. According to my spl meter I have pegged 130db on a few occasions, but on average 126-128db read out is what I get, with 116-117db around 15hz(test tone). I will update in the PSA thread to not clutter this thread. I am just trying to show you examples.
Looking Forward to seeing what those Beatly Triax's belt out down into the lower octaves. I am betting 115-117db @ 10hz.