Localization of sub

I have a Sunfire true subwoofer 1 which was updated last year but you hear the sound coming from that corner of the room. It sits in the left rear corner of the room and unfortunately is the only placement. It has a 40ft cable which links to a Marantz 19. Is there a way to compensate or trick the subwoofer with the distance setting on the receiver or is the that one of the problems with the setup I have or with Sunfire subs? Any suggestions or thoughts would be appreciated. I'd hate to get rid of the sub without exhausting the solutions.

Thanks Brian