Now when you say clustered do you mean next to each other in a line or stacked on top of each other.
I ran it both ways it seems that stacked on top of each other 2 high the bass will be higher and travel a bit farther.
but the bass doesnt seem to travel far. maybe 10 feet or so.
The 2nd picture, with the 4 stacked 2x2, is correct. How many subs were you using, total, at this outdoor fun-fest?
the very top 280 seems to be kind of useless at that high. It would not really be able to hit anyone i might try and figure out some way to angle the 280s.
You want the bottom-most DR280 centered and level ay around ear-height, approximately 65" off the ground. Because you are "ground-stacking", the DR280 stacked on it should be basically dead level, or a few (2-3) degrees tilted forward at the face of the cab.
As for the subs, if you are losing almost all bass at 10', there is a phase problem. 1 or more of your cabs are playing out-of-phase. You need to not only double check your cabs, but you also need to check your cords, DSP/crossover/limiter/whatever outboard gear you are running and the amps, for a phase switch. They should all be off. To find what cabs may be wired out-of-phase, hook 1 up, and play some bass or sine waves. Add a second cab and it should get louder. If it get softer, check the internal wiring of that cab. Do this for all the sub cabs you use.