What is a Subwoofer? Understanding how a Subwoofer Works

Do you love the bass? Have you been looking for a way to get that deep, low-frequency sound in your car or home stereo system without having to spend hundreds of dollars on an expensive subwoofer? Well, you are in the right place! A subwoofer is a speaker that reproduces low-frequency sound. They are typically used in home stereo systems, PA systems, and sound reinforcement systems. Using a subwoofer aims to create “fuller” sounding audio by filling in the area below 150 Hz where human ears can’t perceive any sounds.

Choosing the right subwoofer can be a challenging task. So how do you choose a good subwoofer? Before buying one, it would be best to consider many things: budget, size, power handling capability (RMS), type, sealed vs. ported enclosure design, etc. These factors vary from each other but choosing more than one will play a significant role in your final decision. So, what is a subwoofer? This article will cover what a subwoofer is and how you can fix it when it stops working.

What is a Subwoofer Speaker and Why do you Need one?

What is a subwoofer? A Subwoofer speaker is a device that reproduces low-frequency sounds. By only using high-range multimedia speakers, you are neglecting the lower frequencies of the sound spectrum. Therefore, having a dedicated subwoofer helps to expand your listening experience without cluttering your room with big speakers. You can call it an affordable alternative for a surround sound system! But what exactly does “low-frequency” mean? The term low-frequency refers to any sound with a frequency below about 1,000 Hz (the higher limit of human hearing).

A single subwoofer cannot reproduce these very low frequencies but acts as a single speaker to reproduce all the frequencies of sound waves into low-frequency audio. There are two main types of bass drivers commonly used in-car audio systems: dynamic woofers and balanced armature drivers. A dynamic woofer uses an electromagnet instead of a permanent magnet to create a magnetic field that moves a voice coil through a cone attached to it. The cone then pushes against air (wind), creating sound waves.

Balanced armature drivers also move air, but they do it using a diaphragm that moves an iron core attached to two magnets rather than moving, large cone-shaped membrane like in dynamic woofers. This creates a more accurate sound reproduction, especially in the higher frequencies with less distortion. However, it also means that you will not push as much air creating less bass response. Some subwoofers use magnetic and balanced armature drivers to reproduce different frequency ranges, while others have just one drive unit. So why do you need a subwoofer speaker?

  • Improve sound quality

A good subwoofer system will make your music and movies sound like they were meant to! For example, in 50 Shades of Grey (the movie), there are no explosions or gunshots, but the bass response is so intense that it gives this scene a special feel. If you only used multimedia speakers, you would not have experienced such a feeling.

  • Enhance surround sound

By using multiple subwoofers, you can turn your regular home theater into a true 5.1 multi-channel surround sound system easily and at a low cost! All you need is one center speaker to reproduce the voices and then add two pairs of identical or slightly different side speakers plus one extra subwoofer for low sounds. You can adjust the volume levels of each speaker manually so that they don’t create a distorted sound.

  • Boost your car stereo system

Car subwoofers can be placed behind each seat in the trunk or under the seats and connected to your car audio system. You can also choose powered subwoofers which have built-in amplification.

What Does a Subwoofer do? (Active & Passive subwoofers)

A subwoofer adds depth and quality to sound and an overall pleasurable listening experience. You can add a subwoofer to any receiver or amplifier with speaker wire output jacks, even portable music players such as iPods and MP3 players. Even if your car or stereo system cannot play very low-frequency sounds well, adding a subwoofer will help you boost the existing bass performance of your system. If you have ever wondered what home theater means, then this is it! Because of their size and physical limitations, a typical speaker cannot produce these lower frequencies.

The walls, floor, and furniture will absorb much of the sound produced by a speaker, so most people notice only the higher notes from bass or low-frequency instruments like a cello or bass drum. Typically, a dedicated subwoofer is needed because it can produce those deep lows that add rumble and punch to your favorite music and films. There are also two main types of dedicated subwoofers: active and passive units. So, what does a subwoofer do? Let us look at how each one operates.

Passive Subwoofer

A passive subwoofer contains its amplifier and requires a minimum of two audio cables. It does not have an onboard power amp like other speakers, so its low-frequency sounds are reproduced using the subwoofer driver. Passive subs can be quite large because they require more room for both the speaker and the internal amps that produce many basses. You should check if your home theatre receiver has enough power to drive these types of subs before purchasing them. Otherwise, you could end up with distorted or crackling bass sounds from your subwoofer at high volumes.

Active Subwoofer

An active subwoofer has built-in amplifiers, which makes it easier to set up and install. They also take up less room because they have a built-in power amp and speaker. These subs are normally easier to use with home theatre systems because they don’t require an additional amplifier or cables for the subwoofer. But remember that active units may need to be turned on separately from your speakers – most AV receivers give you the option to turn off your subwoofer if it’s not required.

Despite their differences, both passive and active subwoofers provide great low-frequency sound in your home theatre system. Because of their sizes, however, you should check the manufacturer’s specifications before buying them to ensure that they are compatible with the amplifier power of your AV receiver or amplifier.

Why is the Bass Speaker Not Working and How to Fix it

When dealing with a bass speaker, keep in mind that the larger speaker is mounted in a sealed chamber known as the “pot,” which holds the jack socket. This forms part of the pick-up assembly, and in addition to being an amplifier for sound from the bass strings, it provides induction balance between the strings, i.e., each string has exactly equal induction with respect to one another when held at rest within the magnetic field of the permanent magnet pole pieces. It also increases sustain time by acting as a mechanical filter to attenuate high-frequency harmonics produced when the string moves back and forth over an asymmetrical point on its path. For example, where it leaves or enters a pole piece.

The second smaller speaker inside its pot works in conjunction with the larger speaker to produce a combined bass tone with warmth and clarity. They are wired serially, i.e. The power from the amplifier is applied to one pot which then distributes it equally across both speakers in series. Therefore, if one of them should fail, this will reduce the total impedance presented by both speakers at once to half its normal value. This can result in excessive current draw from the amplifier resulting in substantial distortion, especially on high volume settings where preamplifier gain for maximum output might be raised.

This could also damage your amplifier since a lower impedance load means greater current flow through other components like capacitors causing additional heating. It may even cause damage inside the amplifier’s transformer due to overheating the iron core. Such overheating would be indicated by a rising temperature of the transformer itself when operating under normal conditions. Still, you would be unlikely to notice this since it takes place over a period of time.

Below are the 7 common reasons why your bass speaker is not working:

1. Damaged Amplifier

There may already be a problem with your amplifier, and it must be repaired or replaced. Excessive current draw from previous problems like a bad cable connection can fail the bass speaker. In addition, some amplifiers allow for higher power ratings than others. As mentioned above, an excessively high current draw could cause problems with your amplifier in the long run: it might overheat and damage it.

2. Con seal failure

These speakers are known for having glue failures at high humidity over a while. This leads to the two pot halves separating and, in turn, reduces or completely cuts sound output from one or both speakers. This could be as much as 30dB if all strings on that speaker have failed and can cause serious malfunctioning, e.g., low volume levels, distortion, etc.

3. Driver magnet failure

The smaller speaker is only used to help lessen the load on the amplifier while also giving some warmth and clarity to the sound emitted. It does this by being wired in series with another speaker that has a permanent magnet inside it, which means that if it fails due to wire overheating, there is still enough impedance provided by the other speaker so as not to overheat your amp. This will reduce output from both speakers equally but will have no effect outside of the cosmetic value of keeping both pots intact.

4. Short circuit:

Short-circuiting is when the two pots join the outer terminals together having two wires from different pots touching each other. Short-circuit results when one of the speaker’s connections in the pot and either connection pin on an octal socket touch. In other words, wiring both speakers incorrectly with no cable plugged into the smaller speaker’s input. The above-explained problems that may occur with these types of amps are just examples of what could go wrong due to neglecting safety procedures or shoddy installation.

5. Old age:

This would lead us back to the same old problem of gassing the voice coil (tweeter) and eventually burning it up. You might be lucky enough to get away with just knocking out some tones until it dies off, but you will need to replace this part in most cases. In addition, any resonating cones will be blown off, so expect severe problems on this speaker in case you have no idea on how to fix it.

6. Mishandling:

Any physical damage can ruin these speakers because they efficiently transfer vibrations through the cone (voice coil). Even experienced technicians don’t get away with mistakes, e.g., using screwdrivers or other objects to pry open connections without first marking their position. This is especially when working on a powered speaker where a misplaced screwdriver can contact something hot like an amplifier transistor and short circuit it. Even accidentally dropping your speaker from a height onto a hard floor could result in permanent damage. This may only manifest itself later down the track requiring a new placement of parts before it fails with strange bass sounds coming out at random times that you might think were caused by something else. Ensure to store it in a place with enough space.

7. Wrong Wiring

When testing for open voice coils, the amp should be working inside its clean range using a nominal input of 1kHz, marked on your input gain control. Turning up the volume with the speaker disconnected (or blown) and tapping lightly around the cone area will indicate if this is the problem or if it may just need re-coning. There is nothing worse than taking your amp apart only to find out that all you have to do is redo some glue joints. So take time to make sure it’s dead before doing anything drastic. Remember, these speakers are very inefficient, reaching only 87dB SPL at 4 Ohms which means they can generate over nine times as much (watts) per unit. If you have a passive bass and want to use an amp, the simplest solution is to wire correctly. You connect the speaker jack with the right connector for your amp.

How to Fix a Dead Bass Speaker

When fixing a dead speaker, there are several steps you need to follow. If you replace a speaker that works with a new one, then the old wiring will no longer work since different speakers have to be wired differently depending on their impedance. It is best to always wire your speaker cables correctly by buying them long enough for all eventualities. Also, Impedance matching ensures that only the correct amount of power flows between your bass amp and the speaker cabinet. The recommended load for an amplifier is usually 4 ohms, but it can sometimes also be 8 ohms or 16 ohms.

Checking for this possibility is best done with an ohmmeter (multimeter) applying power to the amplifier while connected across its power terminals and measuring any resulting voltage drop between them. The only reliable test method is to use another bass amp plugged directly into your mains supply without any intervening extension cables or adapters to measure if the excessive current draw does exist and is causing problems. Incoming mains voltage should always be checked first before resorting to more expensive equipment like an oscilloscope which could easily cost as much as some quality bass amps. Note that some bass amps also use an octal socket (8-pin) for the larger speaker.

Below are the 10 steps you should take to fix your bass speaker:

  1. Test your amplifier with another bass amp. This will spot any problems immediately. If you don’t have a second amp, try borrowing one from a friend or professional who might understand what’s going on with your speaker system and can help you figure out the issue faster.
  2. Switch out components in your signal chain (cables, patch cables, effects pedals) until you track down the problem component. Note that if the old speaker was blown, chances are a new one won’t work either since it could be an internal part like a coil that is no longer working properly. In other words, it is more likely than not that whatever caused the old speaker to fail also may have damaged other components in your speaker.
  3. Check all the connections and try swapping out different amps with a known working one with the same size speaker as yours.
  4. If you don’t have that kind of access to another amp, switching out speakers is often done when trying to diagnose problems since your new speaker might work despite having been blown for some reason but still not working for you.
  5. Make sure your amplifier is not on “Bridge Mode.” This will send twice the power to each speaker, causing damage because it creates twice the heat inside the transformer.
  6. Make sure your volume is turned down or off altogether when turning your bass amp on or off so as not to create a loud pop sound through your speakers.
  7. Make sure you have plugged all the cables in properly. If your amp is on “bridge mode” and turned up to full volume, this could damage your speaker.
  8. When not using an amplifier, make sure the power switch is off, not creating a loud pop sound when powering it back on later.
  9. You might be playing too loud for your speaker system since most amps are designed to go no higher than 0dB, with some having cut-offs even lower at -3dB. Try lowering the pre-amp gain or output knob until it stops clipping.
  10. Your bass speaker may be blown and need replacement. If your bass amp is fresh out of the box and still under warranty from the manufacturer, they will repair/replace it free of charge if it is found to be defective. Also, questions regarding how to correct the defect will sufficiently be answered by the manufacturer.

What is the Difference Between a Speaker and a Subwoofer?

A speaker is an electroacoustic transducer or a device that converts an electrical signal into sound. It gets power from an amplifier and changes the signal coming from the amplifier to a high-power sound using a loudspeaker. Speakers are often used in home theater systems, stereos, computer speaker docks, PA systems, televisions, headphones, telephones, and many other devices that can be used to produce sound. A subwoofer has one driver only, while a speaker can have up to five drivers that make sound independently.

A subwoofer is a dedicated speaker designed to produce low-pitched audio frequencies known as ‘bass.’ The typical frequency range for a sub – woofer is 20–200 Hz. Subwoofers are intended to augment the low-frequency range lfe of loudspeakers covering higher frequencies and provide deep bass sound in applications such as musical concerts, public address systems in large buildings, movie theaters, and nightclubs. Subwoofers are made up of woofer drivers mounted in a loudspeaker enclosure – often just a simple cube lot with a round or square port on the front and back.

How much does a Subwoofer cost?

Subwoofers are affordable! Depending on size, quality, and features, you will find a good value purchase at around $100-$300, with bigger ones costing up to $1000. Remember that the smallest is 8″ while anything smaller than 15″ would not produce enough sub-bass reflex. A powered woofer often costs less than a passive one because it has an amplifier inside. However, you will need to make sure you have the correct input and power output of your audio system, usually available on the back of your receiver.


We believe we have comprehensively answered the question: what is a subwoofer? When you add the subwoofer to your audio system, it helps create a more immersive and realistic listening experience. This is because the low bass frequencies are not as directional or easily absorbed by walls as higher frequency sounds are, so adding a subwoofer will help fill in any gaps that may be left behind from your speakers alone. The best part? Your neighbors won’t complain about how loud your stereo is!