Some amount of boominess results from having a sub running too hot to attempt to overcome the missing bass due to nulls. Treating a room and/or adding multiple subs smooths out the overall room response and allows for a more even sound free of booms or missing bass.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris