Subwoofers may not be as glamourous as other loudspeakers, but you shouldn’t treat them like black sheep. Those bass-pumping speakers add the thump that will make you feel those car crashes and explosions in an action movie or the hip-shaking groove of your favorite tunes.

Subs come in two main flavors: active and passive. Active subwoofers have a built-in amplifier. Passive subwoofers require a free channel on your receiver or multichannel amp. The advantage there is if you have an unused amplifier channel, it won’t be wasted if you occupy it with a sub. But subwoofers tend to draw a lot of power, so you might be losing some dynamic range in your main channels if your subwoofer shares an amplifier with your main speakers. Using an active sub can help increase the dynamic range available to your full-range channels and improve your system’s overall performance.

In addition to deciding between an active or passive subwoofer to buy, there are plenty of things you should know about these audio-enriching boxes. Here are five more sub tips to keep your system from sinking, courtesy of Wisdom Audio’s Jon Herron.

1. In a high-quality, properly calibrated system, the bass is authoritative and completely integrated with the rest of the music. You might think that the subwoofer is not playing at all—until you turn it off and realize how much you’d be missing without it. If the subwoofer calls attention to itself with boomy sound that seems separate from the rest of the music, or if you can easily figure out where it is in the room, something is not right.

2. Really good subwoofers will not only shake the room; they will also reproduce musical pitch in the deep bass with great fidelity. Many people have never heard a system that does this well, but the lowest notes on an upright bass or the pedal notes of an organ both have well-defined musical pitches that the ear can easily hear in live music. That same pitch definition should be there in reproduced music as well.

3. In terms of what size sub you need for your system, much depends on the room, on the program material you plan to play and on how tempted you are to crank it up. Here’s a reasonable test: Compare the size of your dealer’s showroom with the size of your room at home. Make allowances for adjoining, open areas (like a large arched doorway that cannot be closed off). If the two spaces are roughly similar in overall volume, ask your dealer to crank it up in his demo system. If it seems loud enough there, it will probably be fine at home.

4. Is there an ideal placement for the sub? The answer is a definite maybe. If the woofer is designed well, and there aren’t any rattles or buzzes that would clue you in as where it is, it is really difficult to point to where the woofer is located in the room. That’s a lot of ifs, so most people play it safe and keep the sub near the main speakers, in the front of the room.

5. Should you make it a .2 system with more than one sub? If you feel you need more bass, you are far better off buying multiple subwoofers and placing them carefully around the room. This will give you both better quantity and better quality. Think of it this way: The “hills and valleys” of one woofer can fill in the “valleys and hills” of the other. Working together, they can significantly level out the irregularities that the room imposes on their responses.