Imagine Die Hard without explosions, Bond without the bullets, or The Matrix without kung-fu. Translation: Speakers are nice. However, if you're serious about sound, you may want to include a subwoofer in your home setup. To put it simply, the subwoofer is the heart of the system when it comes to low-frequency sounds. While the sub may not look as cool as the other speakers in your home theater readout (although certain models can!), this is the unit that can put you in the middle of the concert or the action, all from your living room couch. It makes music and movies (especially action scenes) seem that much more arresting and lifelike. The typical human hearing range is about 20 to 20,000 Hertz (Hz). A subwoofer handles the low end of that range, providing the smashes, crashes and thumps. This type of sound requires its own, fairly large driver. The average sub includes a woofer somewhere from 5 to 18 inches in diameter. That's kind of a large spectrum, however. So how to decide which subwoofer is right for your room?