How Does A Subwoofer Work? [ All You Need to Know ]

Love subwoofers and want to know how they work? Well, you have come to the right place because in this article we are going to tell you everything you need to know about how subwoofers work. From its purpose to the mechanics of its individual components and its different types. So that the next time you want to buy a new subwoofer, you can make an informed decision.

How Does a Subwoofer Work

Buying a subwoofer makes sense only if you know how it works and if you really need one, let’s start from the basics.

What is a Subwoofer?

A subwoofer is a type of loudspeaker that, when attached to a speaker, amplifies the audio and produces a deeper bass. Through this, you are able to actually feel the audio, and so your listening experience is taken to the next level. The way a subwoofer differs from a traditional speaker is through this ability to reproduce low-frequency sounds and better quality audio. Also, a subwoofer on its own cannot produce audio; it needs to be connected to a speaker to work.

Subwoofers are quite versatile, and there are different ones available for different purposes. For example, you have subwoofers for cars that are specific to your car speakers and suitable for the acoustics inside your vehicle. You also have subwoofers for home audio, through which you can experience high-quality sound while watching movies, listening to music, etc.

There are also subwoofers for cinemas that produce strong, impactful audio for a large room full of people. And there are subwoofers for an even larger scale purpose like concerts, clubs, and large outdoor events, and serve the purpose of producing low bass without any distortion for a clear and loud sound.

What does a subwoofer do?

Although some people might confuse subwoofers with ordinary speakers, they actually are quite different because of the range of frequencies they are able to produce. Speakers usually produce higher frequencies and are not able to produce much lower ones. While subwoofers, on the other hand, are specially designed for producing quite low frequencies through which you are able to feel the bass.

This frequency depends on the type of subwoofer. If it is for a lower scale everyday use, like for cars, or homes then its frequency can be around 20 to 200 Hz. But in the case of high-end subwoofers that are used for concerts or clubs, they are able to produce frequencies lower than 100 Hz or even 80 Hz.

Subwoofers also produce quite loud audio. This makes them great for places like cinemas and concerts where there is a large group of people due to which loud audio is required in order to reach everyone. Along with being loud, the sound also needs to be clear and free of any sort of distortion for the enjoyment of the people, and subwoofers do fulfill this criterion.

Also, subwoofers provide you with the option of equalization. With the help of this, you are able to adjust the different frequencies of your audio by boosting some frequencies while completely cutting off others. With the help of this feature, you are able to get audio with frequencies perfectly tailored to your liking.

The Components and Construction of a Subwoofer

To understand how a subwoofer works, we need to take a look at the way it is constructed and its different components. This is because the way sound is produced and amplified in a subwoofer depends on these different components and the way they interact with each other. There are various elements in the mechanics of a subwoofer, and each of them is equally important for making it work properly and enabling it to produce high-quality audio.

The first element in the construction of a subwoofer that we need to take into account is the Basket. This basically holds all the other parts of the subwoofer, which is why it needs to be quite strong and sturdy. The basket provides structure to the subwoofer and comes in different types and materials. An ideal basket needs to be strong enough to protect the rest of the components and prevent resonance, as well as light enough to be transported easily.

Apart from holding all the components, the basket also has other purposes like preventing the voice coil of the sub from overheating. This is done with the help of slits at its base that provide an opening for air to pass through the inside of the sub and cool down its internal components. The basket is also where the terminals for your speakers’ leads are situated, through which you are able to connect the sub with your speakers.

The Suspension System

The next component of a subwoofer is the surround. It is a flexible ring around the cone of the sub that connects it with the basket. Although it might not seem like an important part of a sub, it is quite vital to your subwoofer’s suspension system. This is because it keeps the cone perfectly centered, and therefore prevents extra stress from acting on the voice coil. Also, it helps bring the cone back to its initial position safely as it moves back and forth when audio is being played.

Because of all this, along with being flexible, the surroundings also need to be quite strong. It is usually made up of either foam or rubber; both have their own advantages and disadvantages. Foam is more lightweight than rubber and provides a dampening effect to reduce its resonance, but it is less durable. Rubber, on the other hand, is more durable but less flexible than foam. Both types of surrounds also have different effects on the audio of the subwoofer, which is why it all depends on your preference in the end.

A major component of a subwoofer is the cone, also known as the speaker diaphragm. This is also part of the suspension system of a subwoofer, with its purpose being to move back and forth to push the air and produce sound waves. This is why the cone should be lightweight but stiff and unyielding so that less force is needed to push the air without it getting deformed or damaged.

The cone of a subwoofer can be made from various materials, one of the most common of which is a special type of paper. This makes the cone lightweight and able to provide dampening to eliminate its own resonance. And while a cone made from this sort of paper can provide amazing audio, it usually lacks durability. Other materials from which the subwoofer cone can be made out of are metal, kevlar, and a type of plastic called polypropylene.

Another part of the suspension system of a subwoofer is the spider. This is a ring made up of flexible material that connects the cone to the voice coil as well as the frame of the basket. The spider is responsible for the linear movement of the voice coil and the cone, keeping the former properly centered. And the spider controls the magnitude of the movement of the cone and the voice coil; it greatly affects the audio production and quality. Therefore spiders come in various designs and sizes to suit the different purposes of different types of subwoofers.

The spiders need to be quite strong since they have to go through the most stress, which is why they are made up of materials like copper, aluminum, beryllium, weaved into cloth. This is because these materials are conductive and well as flexible, and the cloth provides them with enough structural integrity to keep from deforming.

The Motor System

Moving on from the suspension system, the next components are part of the motor system of a subwoofer that is responsible for moving the suspension system and producing the actual audio. The main component in this category is the voice coil. This is made up of two parts, the coil and the former. The coil is a group of wires, made up of a conductive material, wound tightly around a cylinder. While the former is the name for the cylinder that is supporting the wounds of the coil.

The voice coil takes the properties of an electromagnet when an AC current is passed through it. And so it creates an alternating magnetic field around it, due to which it is able to move up and down. And since the voice coil is connected to the suspension system, it also moves the components in that system along with it.

The next component of the motor system is the magnet. This works together with the voice coil to produce the linear movement of the components. The way this happens is that when the alternating field is produced in the coil, it cuts through the existing magnetic field of the magnet resulting in a force applied on the coil that makes it move up and down.

Lastly, we have the top plate. This is situated on the top of the magnet and attached to the framework of the basket. The purpose of the top plate is to direct the magnetic field of the magnet to that of the coil in order to produce the linear movement in the audio coil. The top plate is usually made up of low carbon steel due to it being a cheaper material as well as its ability to provide a greater flow for the magnetic energy passing through it.

The Way a Subwoofer Works

Now that you are aware of the mechanics of a subwoofer, it will be easier for you to understand the way it works. When you connect a subwoofer to any sort of audio receiver, the latter sends an electric current to the former that carries a low-frequency signal. This current then passes through the subwoofer, and the low-frequency signals are then amplified with the help of the suspension and the motor system of the subwoofer.

Basically, as the current passes through the audio coil, it moves up and down according to the frequency signal. The audio coil then moves the suspension system of the subwoofer at that frequency that further produces sound waves by pushing the air particles to and fro. And so, the audio that was fed into the sub through the audio receiver is reproduced with a larger amplification and a low bass that is suitable to the frequency signal.

And so, through this process, you are able to enjoy the low bass and frequency audio that a normal speaker is not able to provide. This is because, in normal speakers, a lower frequency and bass coupled with high amplification is always accompanied by distortion. While subwoofers, on the other hand, produce minimal distortion at high volumes and provide you with a more immersive listening experience. Lastly, learn what’s the difference between a subwoofer & a speaker.

Types of Subwoofers

There are two different types of subwoofers, passive subwoofers, and active subwoofers. A passive subwoofer needs to be powered by an external power source and can be tuned easily. This can be either an amplifier or a receiver. This is because they require more power in order to produce audio with an extremely low frequency. Along with its ability to produce such low frequencies, a passive subwoofer can also be connected to other subwoofer units. This makes it the best option for larger areas or more intricate setups like for large home theaters or outdoor events.

An active subwoofer, on the other hand, is one that does not require an external power source as they have one built-in. This makes them quite easy to set up as you don’t have to bother with connecting the sub to an amplifier or any other external power source. Also, it has a small build that lets you place it wherever you want. All of this makes it a perfect addition to your medium home theater system.

FAQs

Wrapping Up

When it comes to how a subwoofer works, many people can be intimidated by the technicality of this device. But once you understand the way the components of the machine work and interact with each other, understanding the workings of this machine becomes quite easy.

And so, with the help of this knowledge, the next time your subwoofer seems to be malfunctioning, you can try to figure out the faults in it yourself. Not only that, but knowing the workings of a subwoofer also allows you to figure out which subwoofer is the best for you when you wish to buy a new one.