Sound bar in a box . . . can't understand dialog.

We have a large credenza in our bedroom that houses the TV, video gear and sound bar (a modest Visio) facing the bed. It's become our favorite movie theater. Think a 4'x3'x8' box with doors on front. The "booming" caused by the interior reverb of the credenza box makes any dialog unintelligible.  Tried moving it out a bit when open (a pain) as well as adjusting out lower freq.s and boosting treble. No luck.  

Any suggestions on something more creative would be much appreciated!

ALERT! Wife is an interior designer so anything that does not fit inside box is not acceptable.