"It seems to work well almost regardless of how the subs are laid out."

Comparison of 4 sub quantity and position simulations. Clearly response varies radically. Adding the DBA does nothing above the 80Hz XO point. Subs 1-4 are AudioKinesis swarm and Sub 5 is Talon Roc. Simulation Parameters extracted from web photos. Some will undoubtedly claim bass traps solve the problems shown. Not in a million years! [Considerable simulation time spent to optimize responses for all positions except for Subs 3&4 @ 66%.] Geddes might comment that DSP and EQ are clearly indicated.

Subs 2 & 5 only. This is about as good as it gets.

Sub 5 only. Not much difference to 2 & 5.

Not much different to single sub above. Worse 70-80Hz. Color the bottom octave G O N E !

Worst 'makes no difference' position! Yikes. 'nuff said!

The swarm raison d'etre even bass response throughout a larger listening position. Irrelevant for a fixed seating position for most HiFi listening. [Read Floyd Toole's book]

Compare the response of psychoacoustic smoothing of a swarm vs a pair of correctly positioned and time aligned subs. Color the bottom octave G O N E. Yuk!

Smooth...