scorecardWhat is a subwoofer? How a bass-focused speaker can give your home or car sound system a boost
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What is a subwoofer? How a bass-focused speaker can give your home or car sound system a boost

Ennica Jacob   

What is a subwoofer? How a bass-focused speaker can give your home or car sound system a boost
Tech5 min read
  • Subwoofers are a type of speaker that boost the lowest frequencies in whatever audio you're listening to.
  • These low frequencies usually include bass guitars, pipe organs, deep voices, kick drums, and movie sound effects.
  • Subwoofers are incredibly popular for home theater and car stereo systems, and are easy to set up.

How many speakers do you own? If you count your phone, computer, TV, car - there's probably more than you think. Speakers are basic equipment for anyone who wants to listen to music, watch TV, or even browse the internet.

But for audiophiles who value having a quality sound system, speakers aren't so basic. Deciding what equipment you'll need for the best sound possible can get complicated, especially if you're new to audio tech.

One of the best kinds of speakers you can get to immediately enhance your sound is a subwoofer. These reinforce the bass and richness of whatever you listen to.

Here's everything to know about subwoofers, including how they work, where to use them, and what kind to get.

What is a subwoofer?

Every sound in the world has a frequency. Higher-pitched sounds have higher frequencies, and vice versa.

Regular speakers and surround sound systems can't properly reproduce low frequency sounds. This makes a lot of music and movies sound flat.

A subwoofer (or "sub") focuses on producing the lower frequencies within music, known as the bass and sub-bass, amplified through the woofer.

While regular speakers can allow you to hear the bass, a subwoofer enables the listener to feel the sound. The frequency range, specifically between 20 to 200 hertz, highlights instruments within that range like bass guitars, pipe organs, and kick drums. It also enhances deep voices and movie sound effects like explosions.

If you've ever gone to a movie theater and felt your chair shake when something big happens on screen, it's probably because of subwoofers.

Depending on what devices you already have for your sound system, a subwoofer may be the perfect addition. Subs take away the strain your speakers are under to reproduce the audio's complete sound, allowing you to not only hear but feel how a director or artist intended for you to experience their work.

How subwoofers work

It can be confusing to understand how a subwoofer works. If you haven't seen one in action, know that they're strong enough to send ripples through a glass of water or vibrations down your spine.

Subwoofers utilize speaker drives, or "woofers," (yes, like a dog) within a specific diameter size. Variables like the subwoofer's base size or the targeted frequency will determine the woofer's overall size.

The sound and sensation that subwoofers can achieve are because of components that allow you to reduce or boost the output of particular frequencies, ensuring that woofer cones on the subwoofer and speakers are moving in sync.

Where to use a subwoofer

Deciding what kind of subwoofer you need may take some time. But here are a few tips for those looking to add a subwoofer to either a home theater or car stereo system.

Home theater subwoofer

In general, a home theater subwoofer integrates into your central sound system, increasing the width and depth of a system's soundstage.

The sound waves created are omnidirectional and bounce around the room. Both the room size and furniture arrangement can affect audio, with bass frequencies being sensitive to room factors. There's a chance the waves bounce into each other, making standing waves or bass nulls.

  • Standing waves: These waves are determined by the size of the room and length of the soundwave, creating an excess of bass energy producing a 'boomy' effect that lacks definition.
  • Bass nulls: Occurs when reflecting soundwaves cancel each other out, creating a dead spot.
Related Article Module: The 5 best home theater systems of 2021

Installing a subwoofer into your home might take some work. Try placing it in different spots around the room, like corners surrounded by a sound-absorption device or a filled bookshelf to help reinforce the bass. Understanding the environmental factors in your home, like its natural acoustics, will help you find the optimal position for your home theater.

Car subwoofer

Have you ever pulled up alongside another car playing music so bass-heavy that your car shakes? That's what a good subwoofer does.

Cars come with a factory standard sound system based on their make and model. Most sound systems need to be professionally installed, especially as cars become more advanced.

These are some key factors to consider when shopping for a car subwoofer.

  • Size: The bigger the subwoofer, the richer the bass, so space is essential for placement in your trunk or under a seat.
  • Enclosure type: There are two types of boxes that contain the subwoofer. A sealed enclosure creates deeper bass and is recommended for audio targeting all frequencies. Ported enclosures are louder and are suited for genres like rap and house music.
  • Power: RMS, or average power levels, are connected to the power handling of a subwoofer. A higher RMS means more bass.
  • Sensitivity: Determines how much power a sub requires to produce a particular volume, expressed in sound pressure level or SPL. High SPL ratings are more sensitive and require less power to produce high volumes.
  • Impedance: The subwoofer's electrical resistance is measured in 'ohms' - the impedance of your amp and sub need to match.

Once the correct specifications are chosen and installed, you'll notice a richer sound. Subwoofers offer a better bass response, allowing you to listen to sounds your speakers couldn't reproduce alone. With quality subs in your car, the chance of your music sounding distorted at high volumes is significantly lower.

Popular types of subwoofers

If you have a better idea of what and how subwoofers work, you'll probably need to understand the two types of configurations - passive and active.

A passive subwoofer's power source is an external amplifier with enough power to maintain bass effects through the subwoofer. An active subwoofer has an amplifier built-in, and requires an AC power source or outlet. Active subwoofers will usually be more powerful than passive ones.

Outside of those configurations are various styles of subwoofers, with each style serving a different purpose.

  • Ported: An extra port or hole that allows air to escape to boost the bass level. Sometimes referred to as 'bass reflex' speakers, these subwoofers give a rich and thick sound.
  • Sealed Cabinet: A subwoofer without a port or passive radiator. The sound loses depth but is well-rounded with fewer booms and peaks.
  • Passive Radiator: A port is replaced with two passive radiators not wired to the amp. This allows sound to escape with better range and is common in Bluetooth speakers.
  • Front/Down Firing: This sub is based on the placement of the speakers. Front-firing has speakers pointed forward with the sound coming from the front and sides. Downward directs the sound to the front and ground, ideal for elevated speakers.
  • Bandpass: Separated by two chambers with one part with a port to release radiation from the front cone, this subwoofer allows you to specify the bass levels you want to be reproduced through the speakers.
  • Horn Loaded: It uses sound that would usually leak and spreads it out in various directions through a longhorn speaker. This sub type is known for being the loudest of subwoofers.

Each style of subwoofer has a specific environment it works best in. When buying a new sound system, consult with an expert or sales representative about your individual situation.

Once you have all the necessary information, you can start building your sound system to experience sound the way you're meant to.

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