Jim, I wonder if something is not right with it. No matter how big a sub is you should be able to adjust it to the room. My first HT set up was in a 10x10 room and I had a Hsu VTF3 MkII in it, but was able to dial it down so it never overpowered everything.

Is the gain set too high in the receiver?

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"Nothin' up my sleeve. . ." --Bullwinkle J. Moose