You should think about the bass a bit differently. All the sound isn't "going into" the corner pocket, what you are hearing is a peak caused by destructive interference and comb filtering. You are probably also hearing nulls elsewhere in the room, which has the same cause as the peaks.
Solution is to try moving the subwoofer (for our advice on room setup see
RealTraps - How To Set Up a Room ) and also get bass trapping in the room, especially in areas with big bass buildups such as your corner pocket.
See these pages for more detail:
RealTraps - Acoustic Basics RealTraps - Acoustics Fact & Fiction RealTraps - Filtered Noise