What Does a Subwoofer Do? Complete Guide Step by Step

Big question? Right?

Let me answer you this one, why do we need a subwoofer?

One important reason why we need a subwoofer is that movie soundtracks are mixed with frequencies reproduced by the subwoofer, and that is why the bass (lower frequencies) sounds are often called ambient.

How Does A Subwoofer Work?

What Does a Subwoofer Do? by speakerjournal.com

The woofers in the main speakers generate deep or accurate bass response sounds, but because their areas of the effective radiating area are limited, the bass sounds cannot reach our ears directly. In other words, sound waves do not go straight to our ears as they lose their bass energy.

Low-frequency sounds cannot be reproduced properly by regular speakers or surround sound systems. In addition to these instruments, low-frequency sound effects can also be heard in pipe organ, kick drum, and bass guitar, movie sound effects such as explosions. This results in bass heavy music and movies sounding flat. By using a woofer, a subwoofer is able to produce the lower frequencies found in music, such as bass and sub-bass. A speaker can only reproduce high-frequency sounds. 

Subwoofers ensure that these are both audible and tangible. Hence, filmmakers enjoy using them. You can also keep the size of your other surround speakers a bit smaller by adding a subwoofer. Subwoofers are essential in such a small living room. 

What if we could get a better and louder bass frequencies by combining the main speakers with woofers having a more significant radiating area?

That is what the subwoofer does.

Since the wireless subwoofer is located near the center of a room where there are walls, it reflects the sound waves that come from all directions and delivers them to our ears. Doing so makes us feel as though we can listen directly to deep bass sounds that were originally lost during their propagation through walls by decreasing damping in the woofer’s performance.

Working Mechanism of a Subwoofer

The working mechanism of a subwoofer is really simple, but before that, we all need to know about the different parts of a subwoofer.

Different Parts of a Subwoofer are

  1. Driver
  2. Amplifier
  3. Crossover Network
  4. Enclosure (Wooden Box)
  5. Port – (some subwoofers have a built-in port in the enclosure.)
  6. Feet or spikes (will be discussed later)
  7. Power supply cord and output cord/plug connected to an amplifier, crossover point network

What Does The Driver Do?

The driver is like a tweeter (higher frequencies speaker). It converts or turns electrical signals into sound waves that can be heard by our ears. The size of the woofer influences the low frequencies it can play. There are many sizes of bass drivers available, but they vary in their tonal quality as well as the way they are built.

How Does The Amplifier Work?

The amplifier increases the voltage from the subwoofer driver. It is basically like playing the guitar louder by turning up the volume knob on your amplifier.

Subwoofers also use passive crossovers that divide mid and high frequencies between multiple drivers instead of active ones that do it with electronic circuits, which usually adds to their cost.

The crossover network provides a path for the high frequencies to be sent to the tweeters or midrange speakers, and at the same time, prevents low frequencies from damaging them.

What is an Enclosure?

What Does a Subwoofer Do? by speakerjournal.com

In simple words, it is like a box that holds all of the subwoofers components together. The bass sounds are generated by moving air inside. An enclosure provides a flat surface for the driver to move against and adds rigidity to the subwoofer. A stiffer cabinet allows for better control of any resonances, which is important since low frequencies have long wavelengths that affect a lot of air–more than any other frequency range.

Subwoofers are housed in wooden boxes that are usually made of MDF or particles. They have a port, which is an opening on the back of the box for a better low-frequency response.

Different Types of Subwoofers

What Does a Subwoofer Do? by speakerjournal.com

There are multiple types of subwoofers, depending on the way they work.

1- Passive Type Subwoofer

A passive subwoofers is powered by an external amplifier or Audio/Video (A/V) receiver.  This is one of the most popular types of passive subwoofer, and it uses passive radiator technology. The speaker coils attached to magnets generate low-frequency sound waves inside the unit, and then these are reflected by a passive radiator, which has no excitation system of its own. This makes them capable of generating deeper bass sound system.

2- Powered Type Subwoofer

This active subwoofers uses a built-in amplifier to increase the audio output by having multiple speakers inside the housing. This system is better than passive ones because it generates stronger bass sounds without using any additional amplifiers or receivers. Moreover, all types of sound sources can be used with it.

3- Digital Type Subwoofer

This uses digital signal processing (DSP) to control the sound output and ensure that high-quality bass sound is achieved. The best thing about this kind of system is that speakers do not need any additional amplifiers or receivers, as they have a built-in power amplifier. Moreover, it works well with all kinds of sound sources.

How Do I Place a Subwoofer?

What Does a Subwoofer Do? by speakerjournal.com

Whereas a subwoofer is a nice addition to a stereo setup, this is a must-have for surround sound. Place the speakers away from the listening area or in corners, as they will deliver bass sounds there.

They should be far away enough from the walls so that the reflection can occur. The distance between two speakers and the wall should be at least half of the diameter of the subwoofer. Also, they should not be placed too close to each other and avoid placing them in corner areas because bass sounds play a significant role in this case.

The best place for the subwoofer is under the TV set or against any wall by using stands that are provided with it.

When we want to listen to bass sounds, place the speaker in such a way that it is near our feet.

How Do I Connect My Subwoofer?

What Does a Subwoofer Do? by speakerjournal.com

Connect the speakers to your TV set using a multiple RCA cable, then turn on all input devices such as TV, amplifier and media player. Make sure you select the audio system source of your choice for the media player.

Go to the menu of your TV set and check for the setting that allows you to select a channel for audio output, depending on your needs. Select the media player’s audio source as the one from which you want to listen to bass sounds.

Then turn up the speakers’ volume so that it is only moderately audible when using the subwoofer.

To obtain the best performance, adjust the speaker’s volume and select a setting for audio output in your TV set according to your preferences. Make sure you have turned on the speakers’ power before starting any media player or amplifier.

When we do not want to listen to bass sounds, turn down the frequency of output sound by going to the audio setting in your TV set.

Most subwoofers is very useful in home and other location, and by following the above steps, we can enjoy our favorite songs and movies with a new perception.

How Can We Know Which Subwoofer is Better?

We often hear that “Subwoofer A sounds louder than Subwoofer B”. That isn’t something we should be concerned with.

The good news is, there are many kinds of test signals such as pink noise or sine-wave for testing frequency response of subwoofers, such as RTA (Real-Time Analyzer) and Sweep Test.

Note: All subwoofers have the same maximum level of output so that you can compare them based on frequency response and distortion.

Choosing a Subwoofer

So, to get rid of any worries about which subwoofer is better, we recommend you to look for one that satisfies your needs, such as price and size.

The good news is, there are many kinds of subwoofers available on the market these days. And it’s getting more diverse in terms of shape, material, and performance.

You can enjoy a movie with incredible bass sounds at home without depending on the film you are watching.

No matter which subwoofer brand or model you choose, we hope that it will be a good match with your speakers and bring you sonic pleasure.

You can enjoy videos that have cool bass sounds without depending on the video you’re watching!

We would like to recommend you an amplifier to go with your subwoofer to enjoy the sound of your subwoofer optimally.