Dual vs single sub

Do you want mono bass or stereo bass???

I have (4) JL Audio F-113 subs with my 2 channel.  You can never have too much subs. The problem is that you don't want to have so much bass that it drowns the mids. That being stated, I have a DEQX unit that can dial in the subs to work well with the mains. 

BTW, when I use my Hometheater equipment there are 4 more subs added to the 2 channel set up.

ozzy

@don_c55  
 
You almost never get stereo bass unless your room is very dead and you crossover high. I have a single sub crossed at 80Hz that’s decently far from my speakers, and in my wooden-floor open floorplan with no treatment other than a rug, I almost never hear where it’s coming from.  
  
@bryantdrew  
 
I would say dual Rythmik F15HP, dual bundle brings it to <$2400, they are very “musical” and are +/-3dB down to 10Hz! I mean, if you have money to blow there is also their F18 :).

I think Noble is on the right path here. Look at the difference between the radiation patterns of point source and linear arrays. The trick is in creating a linear array woofer. If two drivers are closer than 1/2 the wavelength of the highest frequency they are to reproduce they will act acoustically as one driver. The wavelength of 100 Hz is around 10 feet. So, if you space subwoofer drivers 5 feet apart they they will act as one driver up to 100 Hz. Say you have a 15 foot wall. Space 4 subwoofers at 5 foot intervals along that wall the outside two being right in the corners. The other two in the center should be pointed at each other with the drivers as close to the wall as you can get them. What you have created is a horizontal linear array subwoofer which minimizes room modes and reflections and takes full advantage of intersection gain. 12" drivers are way more than enough. Many will do fine with 10" drivers.