Bass adds excitement to home theater sound. Whether it's the roar of rocket engines or the rumble of a kettle drum,you need deep, powerful bass to get the full impact of today's demanding movie passages, musical scores and gaming effects. Working within Monster's innovative line of high-performance THX Select Certified home theater speakers, Monster Tower Bass Modules operate as left and right, front and rear low-frequency channels to deliver intense, 5.1 surround sound audio while complementing you existing decor.