I've been thinking about subs a lot lately. One thing that's lacking from many systems is good, clean, loud bass. Almost always you're dealing with something that leaves much to be desired. A huge power alley from a conventional stack. Room boundary effects. Stage resonance. Crappy drivers. Bad gain structure. And mostly nobody notices or cares. In all the things I've been reading though, it seems that if you take your time and come up with really great bass, your mix up above can be held back quite a bit and still seem powerful and engaging.
One of the ideas I tried after reading about some of the stuff Dave Rat has been doing, and also about the flown sub array on the last Metallica tour is finding a way to make the field out in the house as even as possible by trying some unconventional positions.
I recently mixed a band in the restaurant at a race track that had them shoved in a corner of the dining room across from the bar, divided by a walkway. Dance floor right in front of the band, walkway, relaxed seating over by the bar. Typical set up would be a sub and a top on each side of the band and off you go. Stage volume does a lot, the monitor mixes add to the soup and with a little push from FOH you're done.
Not this time though. When we were loading in I directed my guy to drop both subs at stage right, well away from the corner. I got a strange look from him and from the lighting guy as well. The idea was to have all the bass emanate from a single point, no power alley, and no boundary effect from the walls in the corner.
This isn't a very advanced setup as far as subs go so it's pretty easy for anyone to try out. In a lot of situations you can move both tops to the same side to make coverage a little easier. You get slightly better sight lines in a lot of cases but you do sacrifice a stereo image. In doing so though, you can get a lot cleaner image at all points in the listening area because the areas of interference between the two cabinets are minimized. Not to mention you get some gain by having the boxes right on top of one another.
So what did I get with my subs stacked on one side. A happy crowd, a happy band, and happy venue managers. Walking across the dance floor the bass was smooth and even. None of the usual complaints of too much or too little bass depending on whether someone was standing in the power alley or not. The band liked it because they could feel the presence of the drums no matter where they were as opposed to having the same kind of comb filter effect you get on the dance floor side. And out in the house, the bass tapered off evenly right to the back of the room. Listeners could select how much thump they wanted by how close they sat.
Also thinking about subs for larger venues I've been reading a lot of stuff Dave Rat has written, in particular this article about his setup at Coachella a couple years ago. In fact, his blog should be required reading for anyone in the biz. His philosophy is to be smart and stay mellow, who couldn't benefit from that I ask you. So go read that stuff. Twice.