How to Fix Subwoofer Popping or Cracking Noise
(Last Updated On: November 8, 2020)

Are you having trouble with your subwoofer making loud, cracking, and popping sounds? It’s a common problem whereby the sub produces random and intermittent popping sounds that can be quite annoying.

In our experience, we find that sometimes it’s a really quick double pop, at other times it’s a single pop and may occur whether you are using the system or it’s on stand by mode. 

There are a lot of reasons why a subwoofer may be making a popping or cracking noise. It could be due to a dirty signal from the amp or receiver, an underpowered receiver, the auto on feature, interference, overheating, voice coil issues, or clipping. In any case, the main cause of speaker popping and crackling is some form of interrupted current or audio signal.

In this article, we will show you how to troubleshoot and fix your subwoofer popping or cracking noise. 

Quick Troubleshooting Steps 

Before we get into detailed checks, here is a quick troubleshooting method that might help you to solve the problem in a few minutes.

  1. Turn off the receiver.
  2. Ensure the subwoofer is properly connected to the receiver or amp
  3. Turn off any nearby electronic devices that may be interfering with the sub
  4. Move the subwoofer wires away from any electrical cords.
  5. If the issue is still unresolved, and you don’t have any special setting on your receiver, reset the receiver to the factory default settings. You can consult the instruction manual of the stereo receiver for reset instructions.
  6. Try a different sub. If the problem is eliminated when a different sub is connected, the issue is with the original sub. If the problem is not eliminated, then the problem is with the receiver.

If this does not work, go on to the detailed steps below.

1. Disable The Auto On Setting

Do you have the sub set to “always-on” or auto? Many people have corrected the subwoofer popping issue by simply switching the “power mode” from “auto on” to “always-on” or simply “on”.

It’s a quick and easy way to prevent your subwoofer from popping if it works.

Why does this work?

Well, the auto on feature is used to turn on the suwboofer automatically once it detects an input signal. This decreases power consumption and so decreases internal heating.

subwoofer popping noise auto on setting

However, there may be issues with the auto on circuitry that causes the popping. Normally, popping due to auto on is an indication of the failed circuit in the receiver.

To explain, when you change listening modes and the subwoofer stops popping, this indicates that a particular pre-out jack is not being muted or not being muted for a long enough period of time. The root cause of this could be a failed diode or another circuit component in the receiver.

The fact is, depending on the amp, the standby power in “always on” might be nearly as low as it is in “auto on,” so there might not be a significant benefit.

Power Settings and Overheating

We did say that you should switch the subwoofer power settings to always on. Sometimes this only fixes the problem temporarily because sometimes a subwoofer will overheat if it is on 24/7.

In many cases, this overheating can cause popping. Remember, the amps in these subs are quite powerful and will run quite hot and burn out fast. If the always on feature is enabled, manually power off the sub when not in use. 

 

2. Wireless Subwoofer Interference

If your subwoofer is wireless, then wireless interference could be the issue. Wireless interference occurs when signals coincide and affect each other in a negative way, which disrupts or weakens the WFi signal. 

Kill All Source of Interference to stop subwoofer thumping sound

Remember, there may be many devices in your home emitting their own signals, and not just WiFi signals.

For example, your router, microwave, and cell phone all emit signals that can interfere with your subwoofer’s signal. In fact, nowadays almost everything is smart so your smart fridge, AC, fan, and more could be disrupting the signal to the sub. 

To rule out this problem, quickly hardwire the subwoofer to the receiver, meaning make a direct connection between the sub and receiver using an RCA cable or better yet a subwoofer cable. 

If the problem goes away after you have hardwired the device, then interference is the problem. Everything has it’s limits, and wireless is no different.

How To Fix Wireless Interference

The easiest fix is just to leave the devices directly connected, but if you must use WiFi, you can try the following:

  1. Move the sub around the room until the popping sound goes away. However, subwoofer placement in a home theater is important so that may not be the best option. For example, some people like their subwoofer behind their couch
  2. Move your WiFi devices around until the popping goes away. Again, many devices could be causing the problem, and you don’t know which one so that may not be the ideal solution
  3. Shield your subwoofer from other devices. There are various wifi shields that you can use to shield the sub from other surrounding devices but keep it connected to the wifi receiver. There are actual shields that you could buy, but just try foil and see if that works first. 
  4. If you have many other wireless devices, make sure the sub is using a channel that is as far away from the other channels being used as possible.

Your problem could also be a defective subwoofer transmitter. If you have disabled all WiFi devices or anything that can emit a signal and the issue continues, this is probably the culprit. 

 

3. Switch Out The AV Receiver and Amplifier

It is quite possible that the receiver or amp is sending a dirty signal to the subwoofer, causing the popping sound.

In this case, the subwoofer may be sending “pulses” within the audio signal for some unknown reason.

witch Out The AV Receiver and Amplifier

To quickly check if this is the problem, disconnect the RCA cable or subwoofer cable from the sub on the port on the receiver or from the amp, but keep the subwoofer on. If the problem goes away, then the receiver or amp may very well be the problem. 

However, you will only know if the sub is having the issue in stand by mode as well. To be sure, you need to do an additional check. You need to connect a different signal source to the subwoofer. 

Connect A Different Source

Connect a different media source to deliver a different signal to the subwoofer. This could be a DVD player, Blu-ray player, or really any source directly into the RCA jacks on the back of the sub.

Now here is how you go about testing it:

  1. Turn the sub amp volume all the way down and start playing the source.
  2. Now bring the sub amp volume up until you can hear the music and listen carefully. If the popping noise is still there, the issue is the sub amp. If not, the popping is coming from the receiver or maybe something else.

Subwoofer Bass Level

In some instances, of the receiver is the problem, this can indicate a failed circuit in the receiver. A quick fix for this is to can control the subwoofer with the bass level in the receiver.

Check the receiver, and find the settings that can maintain the right bass levels. This can really help when the subwoofer is popping at high volumes. 

 

4. Pulling Too Much Power From The Reciever 

Is your receiver getting rather hot? For example, you may notice that the device stays cool say during a movie but get quite hot when you are playing channel music. 

If your speakers are connected through your subwoofer and draw a lot of power, this may be the cause of the issue.

As your receiver or amp struggles, it will wear out over time and cause the popping sound. To fix this, get a good external amplifier to handle the demanding speakers. 

 

5. Underpowering Your Subwoofer and Power Mismatch Clipping

Normally, underpowering your subwoofer is not necessarily a detrimental thing. All it means is that the sub won’t have enough power and so whatever is playing will sound weak and lack any detail. 

However, it becomes dangerous when the sub is connected to an amplifier that’s being overworked and sending out a clipped signal.

Underpowering Your Subwoofer and Power Mismatch Clipping

What is a clipped signal? Remember sound waves are sinusoidal waves. Clipping occurs when these signals are squared. This happens when the volume of a source signal exceeds the electronic capability of a circuit. This ends up clipping the sound on every cycle.

For example, let’s say your amplifier cannot play a signal more powerful than what 1 voltage of electricity can produce.

Let’s say you increase the volume at the source, the amplifier still would not be able to produce sound greater than what 1V can produce. Instead, it would clip and distort the signal and eventually create a square wave.

When the clipped signal reaches the subwoofer, it tries to drive the sub it a way that the sub is not designed to handle. In other words, the popping noise occurs as the amplifier tries to produce more voltage than it can to meet the demands of the subwoofer, but the sub can’t manage that signal. 

This is because the square signal will try to move the sub’s cone from all the way forward to all the way to the rear in zero amount of time, which is impossible and so the coil just stays stationary.

Current flowing through a stationary coil only heats up the coil. After some time, this may cause shorts and the cone may even tear, of the coil may jam in the magnet’s voice coil gap, killing the sub. 

When this happens, the sub will start overheating which may lead to popping and burn out. 

How To Fix Power Mismatch Issus

First of all, the simple first step is to refrain from underpowering your subwoofer. To do that, check that the power outage from the amplifier matches the subwoofer’s RMS.

An amplifier producing much less power than it should will of course lead to clipping, but also check if it’s producing more power than the subwoofer can handle.

Remember, the poping sound occurs because the signal is trying to get the coil to pop into position back or forth. More RMS power from the amplifier gradually heats up the voice coil and may burn it out.

Apart from popping, another result is that the glue holding the coil wire in place may melt under all the heat, and the coil crashes in its gap. A solution to this is getting a condenser that’s used to steady the power and transmit it out in stable currents.

In addition, keep in mind that a square wave carries twice the RMS power of a sine wave of the same amplitude. The effect of this is that in addition to telling the voice coil to pop into a position, it’s doing it with almost twice the power of the sub’s maximum capacity.

 

6. Voice Coil Shorting

In many cases, subwoofer popping is indicative of voice coil burns at specific areas. The voice coil is a very long string of copper wire wrapped around a magnet and attached to the cone.

subwoofer Voice Coil Shorting

When an electrical signal flows through the coil, it moves in response to the magnetic field produced and therefore movers the cone.

This movement is what creates vibrations or sound. This is how speakers and subwoofers work.  

If the coil is burnt at any point, it will develop shorts which can cause the subwoofer to pop as the signal goes on and off. This is commonly the cause of the issue if the subwoofer is popping or cracking when no signal is provided (when not connected to the receiver). 

 

7. Wired Connectivity Issues

If your subwoofer is wired, you could also have an issue with the wired connection. Over time, it’s not uncommon for speaker cables to loosen.

For example, it could be a lose RCA connection.

subwoofer Wired Connectivity Issues

When the connection is loose, the current is interrupted; thus, leading to popping. This is especially true if the subwoofer pops and hums.

 

8. Replace The Cables

As already mentioned, subwoofer popping or cracking is almost always the result of an interrupted electrical signal. 

Old, worn out and broken cables with shorts can often cause interruptions in electrical current including audio signals. Replace The old subwoofer Cables

This could be as simple as replacing the RCA cable or the subwoofer cable

A quick way to troubleshoot this issue and find the actual source is by going along the cable to see if there are any loose connections. Just simply wriggle the wires while playing audio and you may very well find where the loose cable/connection is.

In fact, you may very well not need to change the cable, you may very well just need to re-solder the connections if it’s clearly a broken cable. It may be simpler to replace the wire entirely, however.

Remember, subwoofer popping and cracking is almost always the result of a current or signal interruption between the audio source and the subwoofer driver.

In addition, a loose connection may also exist in the wire connections to the amplifier, voice coil, or in the subwoofer itself. Carefully check all these wires and ensure that none of them are loose or melted away. Wires connecting the speaker cones and voice coils should also be checked and tightened.

 

9. AC Power Issues

Sometimes dirty power can cause a subwoofer to pop. Remember, AC power is a sinusoidal wave and various issues can cause changes with the pure sinusoidal wave to some points within the circuit in your house. Just try a different outlet in a different room and see if that helps.  

 

10. Subwoofer Pops When Volume Is Down?

In many cases, your subwoofer may be popping when the volume is down. If your subwoofer is popping as long as the sub is powered on, you are likely dealing with a bad amp. 

In addition to that, as we have mentioned before, if the subwoofer is popping or cracking when no signal is provided, the likely cause is a burnt-out voice coil. 

 

Conclusion

When your subwoofer is exhibiting popping and cracking sounds, there could be a wide range of causes.

The most likely issues are a bad voice coil, the auto on feature, the amp/receiver or the actual connection cables.

In any case, the issue can certainly be fixed if you take the time to go through the troubleshooting and find the actual cause. Good luck!