July 20, 2023

5 Tips for Perfect Subwoofer Placement

Article written by SARAH JONES

While you have a lot of flexibility in subwoofer placement, it's best to place your sub at least a foot away from any walls.

Adding a subwoofer to your sound system can take your home entertainment experience to a new level, unlocking a world of deep sonic immersion that draws you inside every song and every scene.

Adding a sub doesn’t just bring the visceral impact of bass you can feel; it also improves the performance of your entire system, expanding its soundstage and taking some of the heavy lifting off your loudspeakers, improving their overall sound.

Finding the perfect spot for your subwoofer can be tricky. You may have heard that a subwoofer can be placed anywhere in the room; while that’s partially true, your subwoofer will perform better in some spots than others. Because subwoofer performance is somewhat defined by its interaction with your unique space, there’s no one-size-fits-all solution, so dialing in the perfect placement can involve some trial and error.

Your room’s dimensions, surfaces, and even the furniture it contains all affect sound. Bass frequencies are particularly responsive to room geometry and surfaces: Low frequencies are less directional than high frequencies, meaning bass sound waves essentially emanate in all directions, sort of like the way ripples radiate outward when you throw a rock in a lake. These sound waves bounce off walls and other surfaces in the room, and as they combine they reinforce each other and cancel each other out, creating resonant “room modes” with boomy areas where you hear exaggerated bass and dead spots where you might not hear any bass at all.

There are two ways to deal with this issue: Add acoustic treatments to your room, or experiment with strategic sub placement. Here, we’re opting for the simplicity of the latter. By following a few simple techniques, you’ll find a subwoofer location that provides the clearest, most accurate bass response and balanced system sound in no time.

Follow the Rule of Thirds

Because reflected sound waves literally double back on themselves, mathematically speaking, some spots in a room will excite room modes more than others. The “rule of thirds” dictates that placing the sub about a third of the way from the wall into the room will produce the most even bass response. If this is impractical, try a spot that’s one-fifth of the way into the room.

Avoid placing a subwoofer directly against a wall (left) or in the corner, where bass reflections can build up.

Avoid Walls and Corners

We know it’s convenient, but placing your sub directly in a corner or up against a wall creates an acoustic amplifier that significantly boosts bass. At first, this may sound tempting, especially if you have a small sub, but this placement just ends up making things sound boomy. If you have to place your sub along a wall, try to find a spot away from the corner and pull the sub 12 to 18 inches away from the wall to minimize bass build-up.

Present a Unified Front

Aligning your subwoofer on the same vertical plane as your speakers will improve your system’s overall performance. By minimizing timing delays between speakers, you’ll eliminate acoustic issues like phase cancellation, resulting in more precise imaging and localization, and better timing accuracy. And, it’ll be easier to optimize and fine-tune system performance without the need for extensive adjustments or corrections.

The Polk Monitor XT10 subwoofer, aligned on the same plane as the XT60 loudspeaker.

Do the “Subwoofer Crawl”

Bust out your sweatpants for this one. Once you’ve figured out some potential locations for your subwoofer, fine-tune placement using the famous "subwoofer crawl" technique: Place the subwoofer in your desired listening spot ideally at ear level (a chair is great for this), put on your favorite bass-heavy track or action movie sequence and start crawling around the room. (You’re probably wondering why we’re asking you to get on the floor. By doing this, your head will be at “subwoofer level.”) As you move around, listen for areas where the bass sounds weak, uneven, or unbalanced. Take note of the places where bass sounds smoothest, tightest, and most consistent (we like to mark each spot with a piece of tape), and try moving the sub to those spots while you return to the listening spot. By identifying the spots with the most even and smooth bass, you can adjust the subwoofer's position for optimal performance.

Work Around Real-World Limitations

Most rooms weren’t designed with subwoofers in mind, and often, especially in multi-use spaces, practical considerations win out. Don’t be afraid to get creative: When we think of room surfaces, we usually think of the walls, ceiling and floor, but don’t underestimate your furniture’s acoustic impact. Sometimes simply rearranging couches or tables can break up standing waves and improve bass clarity. Placing a sub inside a cabinet is pretty much the worst-case scenario, but if you can’t avoid this, try to position the sub so that the driver faces out into the room, and make sure that the amplifier panel is not face down. You can often get away with putting a subwoofer under a table or behind a couch and still get accurate, balanced bass. Wireless subwoofers, such as those designed for any Polk sound bar, give you even more options for overcoming placement limitations.

The MagniFi Max AX sound bar and companion subwoofer.

A Dynamic Duo

Feeling ambitious? Consider going with a two-subwoofer setup: You’ll experience more even, consistent bass throughout the room, and you’ll increase your sound system’s headroom, which will improve dynamic range and minimize distortion while enabling your system to handle demanding low-frequency content with ease. Intuitively, most people like to place their dual subs in a stereo configuration alongside their front left and right speakers, but you can get better performance if you place the second sub diagonally away from the front subwoofer, along the back of your listening area.

Achieving outstanding subwoofer performance requires some experimentation and critical listening. By considering your room's acoustics, addressing room modes, and identifying ideal subwoofer placement locations, you’ll be on your way to unlocking your entire system’s true potential. The reward? A profound and immersive audio experience enriched by rich, deep bass that adds a whole new dimension to your favorite music, movies, and games.