Having dual subwoofers in your home theater system is the way to go if you want the smoothest and even bass effect across your entire room. When two subwoofers are located at strategic positions in the room, it will smoothen out bass nodes and modes for more even low frequency distribution. In many cases, you will notice an improvement in the low end extension as well as greater headroom for a more life-like and cinematic experience.
If you already own a single sub, introducing the second is easy. Modern home theater receivers sport secondary sub outs. Once you have got that down, here is what you need to know if you plan to install a second subwoofer.