Yeah they may be a little more but are they much better? Or would I be better off going with one really good sub like a XXX or Brahama? Which would be better, a two properly powered SEs or a properly powered XXX/Brahama? Just curious.
Adire Audio Brahmas (owner biased).
Better in what sense though?
As far as SQ/linearity is concerned, the Brahmas are a tad better than the XXXs. The XXXs have slightly better power handling, and slightly louder output (it peaks around 30Hz IIRC) however, as much as anyone wants to exagerrate these differences, all I can tell you is they are VERY similar sounding subs.
The RE SE's are in a different class of woofer, in my opinion. They are more geared towards SPL, and do not offer the SQ benefits of the XBL^2 motor structure.
As far as loudness is concerned a lot of it is install-dependant. Enclosure type/size, power, filtering/equalization, list goes on and on. Its nearly impossible to say without actually trying both setups.
Two SE's will have a lot more cone area than a single sub. More cone area=more output (SPL). However, I think you're needs would be met with one Brahma/XXX. It's your call.