ButtKicker

The ButtKicker is a tactile audio device that allows musicians and listeners to “feel” low frequency audio through their seats or floors, providing powerful sound reproduction without loud volume.  The ButtKicker is used by many top music groups, such as Lady Gaga, Maroon 5 and The Rolling Stones and is used in many movie theaters, home theaters, video game systems and car audio, throughout the world.

http://www.guitammer.com