Rick, one of the best methods for controlling deep bass is to have a wall that is not super rigid, such as drywall on studs, and an air pocket behind it before you hit another wall. In effect, each wall acts as it's own panel absorber. The bigger the air pocket, the better.
At the studio i work at, most of it is just standard home drywall on stud construction, but the walls in the control room and the wall in the tracking room are seperated by a furnace room, a kitchen area, and some storage rooms. Each room is at least 6 feet wide between the control and tracking room walls. In the kitchen, furnace, and storage rooms, you have quite a build up of bass. But in the control room, you hear pretty much nothing very low. We do get a tad bleed in the 400-maybe 2KHz region with a loud drummer, but nothing so bad that the monitors don't quite easily get over it.
Neither the tracking room nor the control room have any low bass build up that I can detect. Before some treatments address low mids were applied though, each room or course had the all too familiar "muddy" sound that many around here complain about in similar type of rooms.
Air pockets not only help with controlling low bass, but also help with isolation between rooms. In our case, we are lucky to have rooms between the rooms, so we get low bass control, as well as decent isolation. The rooms between the two rooms though do get hit with quite a bit of low bass in them!
Let's say that in the case that you are setting up a bedroom in your house to mix in. You have standard drywall on stud construction. Any of the rooms on the other side of your "music room" walls will indeed have quite a big of low bass in them, BUT, your music room is NOT going to be getting that low bass reflecting back into the room. Again, the standard drywall on studs construction is acting as a very usable low bass absorber.
Where bass traps come in handy is if you built a room to isolate from the next room, and used something like a layer of particle board, firtex, and drywall. This wall would be in fact VERY rigid, and would keep the low bass in the room. In this case, bass traps will help you out a lot.
At no point do I want to say that bass traps do not have a place in acoustical treatments. BUT, their actual intended application works best when many other acoustical and structural issues are solved in proper studio construction. For many around here who are not as concerned with isolation between rooms as much as just making their room sound a little better, bass traps aren't really contributing much because the walls in the average house do what they do well enough. But, those standard rooms DO in fact have a lot of problems in frequencies that are a little higher than most of these bass trap designs are meant to deal with.
Yes, bass traps can treat frequencies SOMEWHAT up to maybe around 400Hz. But they really don't start doing their things until down around 80Hz and below. Most people do not have much of a problem down that low and lower in their music rooms because of the "improper" construction used in them (by improper, I mean, a 'real' studio wouldn't have walls constructed that way usually. If you look at the "bang for the buck" factor, bass traps are quite an expensive way to deal with low mid frequencies, and DON'T deal with them all that well really when compared to other treatments that are more specific to the "real" problem. Kind of get the concept?
John Sayers has pushed low mid absorbers, and has been in my opinion very nice about not knocking bass traps in this forum, even though he damn well knows for a fact that they won't solve the problems people are trying to solve. He has quietly pushed people to try solutions that actually WORK for the common problems many around here have with acoustical treatments. I on the other hand decided to include bass traps on my "cure-all" list for a little fun.

But in reality, it is not fun at all. I feel I am making a very good and valid point. If one was to look at the common rooms many around here are trying to treat, and listen to what an experienced studio designer has to say about treating them (John), bass traps wouldn't be talked about too often, yet, it seems every other tread lately has been about bass traps.
Sue me for pointing this stuff out guys.

I am just trying to get people to think and learn about what their real problems are, and to get solutions that really work. I doubt that there is much anybody can show me as "good proof" that bass traps are the best bang for the buck solution for most rooms people around here are trying to treat. I hate seeing people lead to believe that they are a priority when they could spend that money on treatments that address far bigger issues in their rooms that deep bass.
Ed