You may have to experience some sort of noise while using a subwoofer in your home theater or car can. One common issue could be the subwoofer making a rumbling noise.
So, you might be frustrated and want to troubleshoot the issue.
In this article, we’ll explain the causes of your subwoofer making a rumbling noise and what are the solutions for that.
Causes and fixes of subwoofer rumbling noise
There are several factors that can cause your subwoofer to produce a rumbling sound. Let’s take a look at those causes.
1. Bad connection or loose wiring
One of the most common reasons for a subwoofer to make rumbling noises is due to loose cables, bad connections, or even wiring problems.
The causes of a wire getting loose could be due to several reasons. Maybe your sub was jarred and the loose wires are causing the rumbling sound.
Maybe, the wire mightn’t be placed properly in the first place.
When the wire or cable gets loose or damaged, it can’t transmit a signal to the subwoofer or cause an interruption. As a result, you have to deal with the noise.
How to fix it?
The first thing you’ll want to do is check all the connections and make sure they’re tight. If you see any damaged wires, you’ll want to replace them.
It’s also a good idea to check the wiring and make sure everything is connected properly.
Know about the RCA cable for the subwoofer.
2. Grounding issue
Another common cause is that the subwoofer is not grounded correctly. Grounding is the process of providing a safe path for electrical current to follow in order to avoid shocks and other dangers.
A subwoofer needs to be grounded to work properly. Moreover, without proper grounding, your woofer is at risk of electrical damage.
If the subwoofer is not grounded, it can cause a rumbling noise. The reason is that the sub will receive an electrical charge that it is not able to dissipate.
This can happen if the ground wire is not connected properly or if there is a break in the wire.
How to fix it?
The first thing you need to do is check the ground wire and make sure it is connected properly. If there is a break in the wire, you will need to replace it.
It is also important to make sure that the ground wire is the correct size. If the wire is too small, it will not be able to handle the current and could cause a fire.
The best way to ground the subwoofer is to use copper wire. You can also use aluminum wire, but it is not as effective as copper wire.
Another thing you can do is to use a ground loop isolator. This device will isolate the sub from the ground and allow it to dissipate the charge safely.
3. A torn cone
This is another common reason for which a subwoofer can make rumbling noise.
The cone is the large, round, paper or plastic component that makes up the front of the subwoofer. It’s connected to the voice coil, which is wrapped around the magnet.
When electricity flows through the voice coil, it creates a magnetic field. This interacts with the permanent magnet, causing the cone to move in and out.
The movement of the cone produces sound waves, which are then amplified by the woofer’s enclosure.
If the cone becomes detached from the voice coil, it can start to rattle and produce a rumble. In some cases, the cone can even become completely detached from the subwoofer.
However, there are several ways this can happen if the cone gets damaged or torn.
One common way is by playing the sub at too high of a volume. This can cause the cone to flex too much, eventually leading to Tears.
Another way is if something hits the woofer. This could be something as innocuous as a toy or remote control.
If a subwoofer is in a car, then bumps in the road can also cause the cone to become damaged.
Finally, age can also cause the cone to deteriorate and tear.
How to fix it?
If the subwoofer’s cone is torn, you’ll need to replace the cone. This is generally not a difficult or expensive repair. However, if the cone is severely damaged, it’s possible that the entire subwoofer will need to be replaced.
4. Separated surrounds
A rumbling noise can occur if the surround is separated.
The surround is the rubber or foam ring that attaches the cone of the subwoofer to the basket. It allows the cone to move freely and produce the low-frequency sounds that we love.
However, if the surround becomes detached or starts to degrade, it can cause all sorts of problems including a rumbling noise.
The problem with a detached or degraded surround is that it can no longer properly support the cone.
This means that the cone will start to move in an erratic fashion and produce a distorted sound.
In some cases, the cone can even come into contact with the basket, causing a rumbling noise.
But, you may wonder how could the Surround get separated.
It can be separated due to a variety of causes such as poor installation, age and wear and tear, exposure to extreme temperatures, or exposure to water and other liquids.
Learn about the stiff subwoofer.
How to fix it?
If you think that a subwoofer’s surround is the problem, then the best thing to do is to take it to a professional for repair.
They will be able to reattach or replace the surround and get the subwoofer sounding good as new.
5. Dirt or dust
Sometimes a simple problem can lead to all sorts of problems like a rumbling noise. Dust or dirt can also be the cause here.
How does Dirt or dust make a weird noise in a subwoofer?
The answer lies in the mechanism of a subwoofer. It uses a cone to produce sound. The voice coil is wrapped around the cone, and when an electric current flows through it, the cone moves. This movement produces sound waves.
Now, if there is any dirt or dust on the cone or voice coil, it will interfere with their movement. This will lead to distorted sound waves and ultimately a rumbling noise from your subwoofer.
How to fix it?
The solution is simple. Just clean the cone and voice coil with a soft cloth. You can also use compressed air to blow away dirt or dust.
6. Too high gain on the amplifier
When the gain on the amplifier of a subwoofer is set too high, it can lead to a rumbling sound.
The gain on an amplifier is the level of amplification that is applied to the input signal. If the gain is set too high, it can cause rumbling by amplifying the low frequencies too much.
How to fix it?
There are a few solutions to this problem:
If you have the gain on your amplifier turned up too high, the first solution is to simply turn it down. If you are using a subwoofer with a built-in low pass filter, the second solution is to use a higher cut-off frequency. The third solution is to use a subwoofer with a higher cutoff frequency.
7. Crossover distortion
A crossover is an electronic filter that separates the low-frequency signals (bass) from the high-frequency signals (treble). Crossover distortion occurs when the filter is not able to perfectly separate the two frequencies, causing the bass and treble to “bleed” into each other. This can cause a rumbling noise from your sub.
How to fix it?
There are a few ways to fix crossover distortion:
– Make sure your woofer is properly calibrated. This can be done with a sound meter and an adjusting tool, or by using a software program like REW (Room EQ Wizard).
– Use a higher quality crossover. A better quality crossover will have better filtering and thus less distortion.
– Use a lower crossover point. By separating the bass and treble frequencies at a lower point, there is less chance of distortion.
– Use an active crossover. An active crossover is one that is built into the amplifier, rather than being a separate piece of equipment. This can provide better filtering and thus less distortion.
8. Faulty or damaged amplifier
If you have an amplifier, then it can also be the reason for the rumbling sound of a subwoofer.
When the amplifier produces sound, it also produces heat. This heat can build up and cause damage to the amplifier.
As a result, the amplifier can’t work properly and will eventually cause the subwoofer to make a rumbling sound sometimes.
How to fix it?
The first thing you need to do is to check the amplifier.
If the amplifier is damaged, then you need to replace it with a new one.
If the amplifier is not damaged, then you need to check the wiring.
Make sure that all the wires are properly connected and that there is no loose connection.
If everything is alright with the amplifier and the wiring, then you need to check the subwoofer itself.
9. A loose or damaged voice coil
A potential cause of the issue can be a loose or damaged voice coil.
What is a voice coil is a subwoofer and why is it important?
The voice coil is the part of a subwoofer that produces sound. It’s a coil of wire that is wrapped around the magnet.
When electricity is applied to the voice coil, it produces a magnetic field. This magnetic field interacts with the permanent magnet in the subwoofer, and this interaction causes the subwoofer to move.
The movement of your subwoofer produces sound waves, which is what we hear coming out of the subwoofer.
A damaged or loose voice coil can result in a rumbling noise because the coil is not moving as smoothly as it should.
The damage can be caused by several things, such as excessive heat, physical damage, or water damage
How to fix it?
If the voice coil is damaged, it will need to be replaced. This is a relatively simple repair that can be done by a qualified subwoofer repair technician.
10. Amplifier clipping
Amplifier clipping is another cause of rumbling noise from the subwoofer. Clipping occurs when the amplifier is trying to output more power than it is capable of, causing the waveform to become distorted. This distortion can cause a rumbling noise.
How to fix it?
There are a few ways to fix amplifier clipping:
– Use a lower volume setting. This will reduce the amount of power the amplifier is trying to output, and thus reduce the amount of distortion.
– Use a higher quality amplifier. A better-quality amplifier will have more power and thus be less likely to clip.
– Use a smaller subwoofer. A smaller subwoofer will require less power from the amplifier, and thus be less likely to cause clipping.
– Use a lower crossover point. By separating the bass and treble frequencies at a lower point, the amplifier will not have to work as hard to power the subwoofer and thus be less likely to clip.
11. Aged or damaged subwoofer
Finally, the rumbling noise can be due to a simple cause like your subwoofer being too old or damaged.
As a subwoofer gets old, the surroundings start to deteriorate.
The deterioration of the surround causes the cone to rub against itself and make a rumbling noise.
Not only that, but an old subwoofer can also have a deteriorated voice coil.
When the voice coil deteriorates, it rubs against the magnet and makes a rumbling noise.
How to fix it?
If your subwoofer is too old and is making a rumbling noise, then the only solution is to replace it.
Troubleshooting the subwoofer making a rumbling noise
Here is the step-by-step guide.
1. Check all the connections
First, make sure your subwoofer is plugged in properly. If you have bad connections, then you will want to check the connections and make sure they are tight.
Make sure the screws of the subwoofer aren’t loose as well.
2. Check the ground wire
If a subwoofer is making a rumbling noise, the main thing you should do is check the grounding. If the subwoofer is not properly grounded, it will create a rumbling noise.
3. Check the wiring
If the grounding is not the problem, the next thing you should check is the wiring. If the wiring or cable is loose, it will create a rumbling noise. Make sure they are tight.
4. Clean the dust and dirt
If the wiring is not the problem, clean the dirt and dust and check the sound.
5. Check the amplifier.
The amplifier is the most likely cause of the noise. You should check the amplifier and make sure it is working properly. Try a different receiver or amplifier.
6. Check the speakers
If you have a home theater, check all speakers of the system and ensure that they are working properly.
If the speakers are not the problem, you should check the subwoofer.
7. Check the subwoofer components
Check the sub’s components such as cone, surround, and voice coils, and make sure they are good.
8. Check the subwoofer
Check a subwoofer and if the subwoofer is not working correctly, it may be defective and you need to repair it.
9. Take the subwoofer to a professional for help
If you can’t repair it on your own, contact a professional.
10. Replace the subwoofer
If all the above fails, then it is time to replace a subwoofer.
Check out my other article on subwoofers making ratting and humming/buzzing noises.
Conclusion
In short, your subwoofer may make rumbling noise due to a variety of causes such as bad connections, improper grounding, torn cone, defective surrounds, too high gain on the amplifier, dirt or dust, malfunctioning crossover, or faulty amplifiers.
If nothing is working for you, and your subwoofer is still making a rumbling noise, it may be due to a damaged or old subwoofer. So, you might have to replace the subwoofer with a new one.
I am Pallab Kishore, owner of Sound Gears Realm. I like to try different sound gears and home theatre systems. I like to share with you my experience with these devices, especially subwoofers so that you can get help to solve any problem.