Subwoofer Makes Loud Noise When Turned Off [Fixing Guide]

Last Christmas, I bought myself a subwoofer. Honestly speaking, it delivers an outstanding performance. Overall, I was satisfied! Until one day, it started making a loud thump noise while I was turning it off.  I was terrified as it feels like the system is gonna blow off. It squeals or rumbles or buzzes loudly.

After a little research, I was able to determine the silly reason and fix it instantly!

Wanna know how I fixed it? Keep your eyes on this article as it will bring to you the top 8 solutions to fix your subwoofer from making such terrible annoying noise.

Why Does My Subwoofer Make Loud Noise When I Turn It Off?

Subwoofer Makes Loud Noise When Turned Off

You might get confused about where this sound is actually generating from. Sometimes this sound comes through the sub, sometimes through the mid or you hear this popping noise out of the entire system.

You might eventually ignore it but ultimately, it will kill your subwoofer.

But why does it make such a loud thumping sound? Well, that is because either your amplifier or head unit loses signal/power before the other. That means both do not lose signal at the same time. Rather one drops out signal before the other, thereby producing a loud thump noise.

Other reasons include:

  • A loose connection. The subwoofer might be connected poorly to the main power source.
  • Faulty circuit. There might be a spark, causing a back-EMF. This confirms that the circuit is defective and needs replacement.
  • Faulty cables. The cables of the subwoofer might wear out. You need to check and replace, if necessary.

Follow This Quick Fix Method To Get Rid Of This Problem Instantly

Here I am presenting a Quick fix method that will help you to fix this problem in an instant. 

  • All you need is a relay! 
  • Just add a small 40amp relay (those are cheap)to the remote wire of your amplifier.
  • This helps you to sync the amplifier and the head unit.
  • After you connect the relay, check if there is any more noise coming from your sub.

8 Ways You Can Try To Fix The Annoying Loud Sound

Solutions You Should Try To Fix The Annoying Loud Sound

Let’s move on to the solutions to get you out of this horrible problem!

1. Running RCA problem

Sometimes the RCA keeps running next to the live wire of the amplifier. That often results in the thumping sound while you turn off the key. In that case, make sure that your RCA wire is shielded. And don’t ever buy open and cheap RCA cables.

For subwoofers, the most popular is Composite Video Cable. This is basically a single-piece yellow plug which works pretty well! And the price is reasonable as well!

2. Turn down the volume

Another way to fix this problem is turning down the volume all the way down.

Yes! Before you switch your system off, make sure to turn down the amplifier volume level to the least. This helps to avoid such annoying sounds.

I would also recommend using a toggle switch to turn on/off your system/amplifier anytime without using the ignition.

3. Install a bus bar

You can also install a bus bar. All you need to do is connect it to your main power supply. Now run the wire to both your amps.

Now if they lose signal, it will be at the same time. And there will be no more loud noise.

4. Replace the faulty amplifier

Your amplifier might turn defective. It could get struck by a heavy object or the remote control might get loose and turn defective. Again, most amplifiers have an inappropriate design that does not get compatible with the system.

If the amplifier turns bad, you have to replace it. Do not go for cheap amplifiers as they turn faulty over time.

5. Active Subwoofer

An active subwoofer might also result in a loud thumping sound. This could happen if your subwoofer gets powered by itself. Some subwoofers have a built-in amp which is why it gets powered and creates a loud noise if you shut off the amplifier.

In such cases, you gotta turn off the sub at first. Then turn off the amplifier and then the power switch.

6. Change Polarity

Sometimes the problem starts with the polarity of the subwoofer connections. You gotta reverse/change the polarity.

To reverse the polarity, you can use an AC Ground adapter. 

7. Get Rid Of Loose Connections

Before judging the cables, you should actually check the connections of your subwoofer. Often the wires/connections tend to get loose. When this happens, you get this horrible loud sound coming from your subwoofer. 

You must make sure that the connections are tight and secure. Check whether the plug is securely inserted into the ends of the subwoofer as well as the power outlet.

8. Check The Ground Connection As Well!

A poor ground connection could also be the reason for such loud noises. To determine whether the ground connection is clean, you have to sand down the grounding location in such a way that it shows only bare metal.

Frequently Asked Questions

So I thought of covering some FAQs here. In case you are still wondering about what actually is going on with your subwoofer, you can go through these most Frequently Asked Questions.

Why is my subwoofer making a loud noise?

If your subwoofer is making a loud noise, then it must be the voltage difference between your vehicle ground and the electrical ground. Besides, your RCA cables might turn defective. You need to inspect and identify the root cause of it.

Where do you ground a subwoofer cable?

If your subwoofer is creating a loud sound and you want to ground it, make sure you connect the grounding wire to a screw on the rear of the sub, while the other end to the rear of the amp.


Finally, I believe that any of these 8 solutions would work out for your subwoofer. And it will thereby, stop making a loud noise. However, if these solutions don’t work out, you might need some technical help from a professional. If you are a DIY person, you should definitely try these fixes yourself at home! Good luck with that!

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