Subwoofer advice sought

@big_greg I have not heard a DBA system and I was really commenting on the first response to the post stating:

Low bass improves the sense of envelopement, feeling like you are in the soundstage instead of it being just in front of you.

I think DBA is probably a good way to combat room nodes and help distribute bass evenly. Good to hear it doesn't envelope you and place you inside the sound stage which would be an unnatural presentation in my view. I would like to check it out sometime, although it would been completely impractical to integrate into my mainly listening space which isn't dedicated to listening - it's my living room. Life's a balancing act of priorities ;-)

That first response was of course me. There's people here for whom no amount of explanation or clarification will ever be enough but since you've muddied it up misinterpreting me yet again I might as well try. 

"Low bass improves the sense of envelopment, feeling like you are in the soundstage instead of it being just in front of you." In hindsight for those short on imagination it might have been better to have said recording venue instead of soundstage. 

Because it seems you've misconstrued me to having said DBA makes it feel like the instruments and singers are way off to your left and right and behind you like some quadrophenia acid trip. When all I really said was it increases your sense of envelopment. 

Which you will know when you hear one, and I would be happy to demonstrate, if we don't have to worry about killing each other being in the same room. Relax you will be perfectly safe. I'm BLS certified which will come in handy when you pass out from the shock of realizing I actually know what I'm talking about.

Truly deep, accurate bass does indeed improve imaging, midrange, and treble, and contribute to a sense of envelopment. It improves midrange and treble because of the way the ear senses volume balance. Two speakers can easily produce enough midrange and treble, its deep bass they can’t do. Low bass improves the sense of envelopement, feeling like you are in the soundstage instead of it being just in front of you. This happens because our sense of space is tied in to very low frequency sound. At very low bass frequencies the wave lengths are much longer than any room you will find in any normal home. 40 feet or longer. So we hear that, our brains assume we are some place big. 

Okay so that explains the why.

Now, how to get this. The good news is its easy. The bad news is it can’t be done with one.

Every speaker no matter what is in the room which as mentioned above is smaller than the lowest bass wavelengths. Because of this they reflect and bounce back and cancel and reinforce. The areas where they cancel and reinforce change depending on the frequency, and where the sub is, and where you are. But they are always there. For every sub. No matter what.

This is why with one sub you have all these problems moving it around trying to get the best smoothest most even bass. You never can get there because all you can really do is move the modes around. You never can get rid of them. Its impossible.

So what you do instead is use a lot of subs. The more the better. Four is pretty good. Then you put them in different locations. This spreads the modes around. Lots of very small modes is way better than a few really big ones.

Its called a Distributed Bass Array. DBA. Do a search. Audiokinesis makes one called the Swarm. Doesn’t have to be a Swarm. Any four subs will work just fine. DBA. Totally the way to go.
https://systems.audiogon.com/systems/8367