I have a huge hump at 30Hz

I am happy with my system and I'm down to working with the room. I have about a 10dB hump in response at 30Hz. At 40 and 25 Hz it is pretty flat compare to the rest of the bass range so I have a pretty narrow range to deal with. The long dimension of my room is about 17 feet which would predict this response. It is not a huge problem since most music doesn't hit that frequency, but I would like to get rid of it. Is there an inexpensive way to deal with this?

I know that Rives makes a parametric bass EQ but I have to think there is a solution for less than $2800. I've read about helmholtz resonators but have yet to find any detailed instructions for building one. I've looked into tube traps but they don't have the high Q I need to get rid of the hump.

I'm thinking that an active EQ may be the only solution for such a narrow band of frequencies. Any ideas?