The two answers already posed are correct. However, there is a third answer (not direct at what you said, but it works). Bass traps. Most people think of bass traps as taking bass energy away, however, there are types of designs that actually change the phase of the bass energy and thus create different interference patterns. The result is both a reduction in the peaks and an increase in the nulls. Will it solve the problem? Don't know without a lot more information, but there's a good chance it would.
speaker/room bass modes
Question: If a room has a 60hz suckout with speakers "A" which have the woofers one on top of the other at the bottom of the cabinet, and you replace them with speakers "B" which have a different woofer configuration, one low and one high on the baffle and possessing a different crossover and radiation pattern, and place them in pretty much identical postions within the room, will the suckout remain? Does the room have the final influence on reproducing the frequecy or can it be overcome with a different delivery from the speaker?