The low end in this room is challenging. I am ultimately not super happy with the sub placement and will move them around until I find a better place for them. There is a suckout in the middle of the room that leads me to believe the short dimensions of 2 sides are contributing to this room behaving more like a small room. So splitting the subs up may be the best option. We definitely have the headroom LOL. I think I may try geddes approach and try to randomize the modes being activated. There are already 9 ported tops around the room contributing loads of 70hz, and the preset hpf on the tops is 40hz, so we are off to a good start
these tops are weird they seem to be tuned pretty low, with an undersized enclosure and excessive xmax. Then they apply FIR filters to flatten phase and magnitude down to around 500hz, as well as correct for coaxial loading geometry, and ultimately apply a very wide q 9db boost around 80hz. It's honestly brilliant and works so well! But it means that my hpf is really not too far from where the hpf is on the subs
I know geddes believes you should leave the mains without a hpf but these are ported so they need it. This is pretty much just as good as a sealed main without a filter. It makes integration very easy as the phase shift caused by the 4th order hpf isn't until out of passband. These are remarkable loudspeakers really, they are shared magnet coaxial too, which I've never seen in person. The HF horn as well as the woofer use a 3" voice coil. Sorry for focusing so much on the loudspeakers I am just enamoured with these designs. They are so out of the box
well it seems as though they may be instrumental in achieving better bass response around the room. Crossing them over higher had negative ramifications in the subs current configuration.
for my 4x T48 build I'm getting started on. I'm going 24" wide. Would you think the single vertical brace still be enough at 12" between or go two for 8" between? To avoid any rattle.
was such a waste of Baltic birch. This grille design is rock solid tho and it's more well supported than most commercial speaker grilles. You would have to really hit that thing hard to leave a dent. Only thing better would have been to curve the grille and supports ever so slightly, but that felt unnecessary and time consuming.
it's complicated on the back end but I've made it easy for the house engineers when I'm not around. I've never designed anything even half as complicated as this, and it sorta blew my mind when it just worked 
I guess that's what happens when you hire a bunch of NERDS 
. This is the greatest challenge of my career as the layout of the venue doesn't provide me a lot of options for dealing with room modes. 
so far though DBA is the most promising with the lowest level of variance.