Subwoofers with room correction built in?

@oldhvymech - my DIY skills are pretty limited so far, but I'm sure this would be a worthwhile approach.

@erik_squires thanks. I know JL is the real deal, but I have high hopes for the elac due to Andrew Jones involvement. 

I am hopeful you can make most self-adjusting subs work.

The parts they seem to do well is room integration and main speaker integration.  The part that is sometimes in question is the bass ends up too dry, which can be fixed by gently boosting the lowest Hz, 16 to 25 Hz and letting it slope downwards about 1 to 2 db/octave until it reaches the main speaker crossover frequency.

For less than $1k you can get the DSPeaker Anti-Mode 2.0 unit with built-in room correction and DSP equalization modes. Other units are out there but I'm not that familiar. These units can be used with your main speakers, in addition to your subwoofers, to take out certain problem frequencies. Some will go to their graves fighting DSP tooth and nail but I would not remove mine. The improvement to the sound of a good system is night and day, no kidding.

+1 @musicaddict Though I tend to buy from miniDSP.  Also, DSP works MUCH better if you have good room management.

I’ll echo the last two posts and add that even the cheap 8033 from Dspeaker, which is only meant for subwoofers, works well, particularly if you dial in the woofers as much as possible (placement, crossover, gain, phase, etc.). I run such a unit from an additional line out on my line stage to feed the Dspeaker, which controls a pair of Rhythmik 15 inch subs. Those subs are not crazy money and really blend well with my hybrid horn set up. Note that the 8033 sums the bass for two outputs so no stereo subs (unless you have two 8033s or buy the fancier Dspeaker unit mentioned above). I don’t really care about that because I’m mainly playing LPs most of which are summed bass anyway and I'm rolling off the subs at 55hz on a 24db/octave slope. Pretty cost effective way to get synergy with a horn/hybrid that does not sound like two systems playing at the same time. It is seamless.