Where to place a subwoofer for optimal sound and bass quality

One of the biggest dilemmas in home theatre setups is figuring out where to place a subwoofer in relation to the rest of your audio system. Many home theatre enthusiasts place subwoofers in one of the room's front corners. This is a great option, because it allows the walls to create boundaries that amplify the bass and keep the low-pitched sounds heading in the right direction. But every room is different, and subwoofer placement deserves a closer look. Here's how to find the perfect home for a subwoofer.

First, it helps to understand the science of sound. While light waves are electromagnetic and can travel quickly through empty space (even in a vacuum), sound waves are mechanical and travel through a medium such as air or furniture. This is why the TV stand vibrates when you crank up the volume.

Sound quality is all about reproducing sounds, and while some speakers provide all of the sounds in one tidy package, others have specialty roles. Subwoofers reproduce low-frequency sounds in audio. They're dedicated to the booming bassline in a song, the rumbling thunder in a movie soundtrack, and all the low sounds that add depth to the listening experience. A complete audio system allows listeners to literally feel the bass. The vibration of deep sounds brings a smooth, complete quality to the listening experience.

The trouble with low notes is physics. High-pitched sounds have shorter wavelengths and lower sounds travel in longer wavelengths. This is an important reason to pay extra attention to the subwoofer. Low sound waves can be the same size as your room, which can create dead spots with no bass.

A subwoofer's placement significantly affects the sound quality. That's why researchers at Delft University of Technology studied where to place a subwoofer for optimal listening. They explain that when a wavelength matches a room's dimensions, resonances called "room modes" occur, which cause inconsistent sound quality. The researchers also explain a phenomenon called diffraction, which is how sound bends around corners and objects, especially at lower wavelengths. In short, there’s science behind finding the best placement for your subwoofer.

Even the most casual listeners can confirm this theory by moving around the room and paying attention to the lowest sounds from an audio track. There's often a surprising variation from a seat in the middle of the couch to a chair on the side.

The researchers used computer simulations to find the ideal location for a subwoofer in a virtual room. In their case, the best spot was to the left of the TV. But while the scientific study of reflections and diffraction can pinpoint the perfect spot in a virtual room, real life is complicated. Every room is different. The dimensions, furniture, decor, and wall textures all change how people perceive sound in a particular room. Popcorn ceilings, tile floors, and marble coffee tables all affect the way sound waves are absorbed and reflected. Even the same furniture in a different configuration can change how people hear soundtracks.

As you consider where to place a subwoofer, you might be surprised to learn there isn't an obvious answer. While corner placement is a good starting point, the room's dimensions, furniture, and even decorative accents can affect the acoustics. When setting up a home cinema system for the first time or looking to improve the bass response in an existing setup, it's a good idea to move the speakers to optimize the sound quality. But pinpointing exactly where to place the subwoofer can be tricky.

A popular method to find the best spot is called the "subwoofer crawl." Sound travels in both directions, so this process involves flipping the listening position and the audio equipment to find the ideal placement. Here’s how to do it:

1. Move the subwoofer to where people sit, at ear height.

2. Play a song with lots of low notes, such as a hip-hop track with a heavy bassline.

3. Move around the room and mark the spots where the bass sounds best. (Use tape, throw pillows, or any easy nearby objects).
4. Review the ideal placement options and rule out any that are inconvenient or not aesthetically pleasing, like a tripping hazard or off-centre location.
5. Identify the sweet spot and set up the subwoofer.

Subwoofers aren't usually stand-alone speakers. Instead, they enhance the overall experience led by the main speaker system. If the audio falls flat because of limited bass frequencies, the direct solution is adding a subwoofer. But not all audio devices are compatible with all subwoofers, so it's important to find the right match. An excellent subwoofer can't compensate for a weak speaker, but it can intensify the audio experience — especially when combined with a high-quality audio system.

External speakers like centre channel speakers, surround sound speakers, and soundbars are designed to improve the audio experience, but you can take it to the next level by pairing your speakers with subwoofers. This combination allows listeners to feel the vibrations and hear low-pitched sounds in a more dramatic and holistic way. For many casual listeners, incorporating a soundbar and one subwoofer into home theatres is just right. But some rooms will still have dead spots where the deep bass doesn't hit, or is dulled by standing waves when two waves are moving in opposite directions.

In that case, multiple subwoofers can significantly reduce the variation, allowing effective equalization. For the fullest bass sound, you should add another subwoofer.

Flatscreen TVs offer high-definition visuals without the bulkiness of previous generations of technology, but what happened to audio? As TVs have gotten thinner, there's less room for built-in speakers. Even the best TVs should be paired with an external speaker system to get the powerful, immersive sound you’re looking for.

Surround sound is a popular option that involves installing multiple speakers around the room. Alternatively, soundbars provide a compact, all-in-one option — or nearly all in one (we'll get back to the subwoofer in a moment). When considering how to choose a soundbar, look at technology options, such as a soundbar with smart features, or those equipped with Dolby Atmos®, which adds a height dimension to the soundscape.

The specific details of connecting a subwoofer to other devices will depend on the input (for example, a smartphone versus a TV), other speakers, and the subwoofer model. Start by connecting the subwoofer to a power source, such as plugging it into a wall outlet or connecting it to the stereo receiver if it doesn't have a power cord.

Then, if it's a conventional subwoofer, look at the TV to find the ports for external audio. These are often labeled "out," "aux," "RCA," or with a picture of headphones. (Note: If the TV doesn't have those ports, a converter might be required.) Connect the subwoofer to the TV using the corresponding cable.

Alternatively, smart soundbar and subwoofer combinations can be paired with an app. In this case, the setup is largely automated.

OK, here's the catch. Scientific studies can identify "perfect" subwoofer placement, but home cinema systems are personal. So, where to place a subwoofer? Ultimately, the process is trial and error. Whether researchers are using computer simulations, or homeowners are using the "subwoofer crawl" method, the ideal position for listening isn't set in stone. There's an art to music and theatre, after all. Whether the subwoofer is in a front corner or placed behind the sofa, the most important factor is personal: Does the system sound good overall? The ultimate theatre-like experience involves good bass that viewers and listeners hear and feel.