Distributed Bass Array configuration

There are circumstances under which a pure 80 Hz tone can be localized and circumstances under which it cannot. Outdoors or under anechoic conditions, yes. In a home-audio-sized listening room, very unlikely. This is because the reflections start arriving before the ear has time to distinguish the first-arrival sound. But notice that I specified a "pure" tone - no additional energy north of 80 Hz.

There are conditions under which a subwoofer crossing over at 80 Hz can readily be localized. Crossover filters are not brick walls, nor do they attenuate the driver’s inherent harmonic distortion (because it occurs after the crossover), and both of these can result in audible and localizable energy north of the crossover frequency. Also if the output from the subwoofer arrives before the output from the main speakers, the subs are more likely to be heard as separate sound sources. And of course if the main speakers are turned off, the subs are far more likely to become localizable at some volume level because any (virtually inevitable) energy they pass north of 80 Hz will not be masked.

If the subs must be crossed over up high, and/or if they have a gentle lowpass filter slope (1st or 2nd order), probably best to keep them near the mains or at least make sure the output from the mains arrives first.

Imo, ime, ymmv, etc.

Duke

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

Geddes, a DBA progenitor, has several pre-conditions before the above statement is true.

For a simulation comparison of the effect of moving DBA subs in a room and system similar to the claimants, see http://ielogical.com/Audio/misc/DBARoomSim.php

Duke nailed it. 

      Here's a good article on the subject of multiple subs that I think is worth reading.  
https://mehlau.net/audio/multisub_geddes/

     My general advice is to also learn as much as you can about how sound waves behave in smaller, domestic-sized rooms and how humans detect sound waves through our body and how our brains interpret/process these inputted senses before creating the perceptions of sound in the room.  Spoiler alert: bass sound waves behave quite differently than higher frequency sound waves in our rooms and we perceive them differently based on their frequency range, too.

Tim