Subwoofer Making Noise without Input; Why this happens, How to Fix?

Subwoofer Making Noise without Input; Why this happens, How to Fix?

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Is sound coming out of your subwoofer without any input? Be it a thumping noise like a heartbeat or a humming noise or other various types, it’s a common problem and quite annoying.

The most common issue is if your Amp is broken. Try opening it up to see if something is wrong like wiring or capacitor. If your amp is at fault then the fastest solution is to replace it. But if it’s too costly for you, you can try using a simple wire hack in the RCA port to fix it yourself or even troubleshoot the amp itself. 

Why does Subwoofer make Noise?

So why is your sub humming at you? The only reason your subwoofer is being noisy without input is that something is broken in your system. If you have wired everything together fine, everything worked out fine, there is nothing broken anywhere your sub will be fine. However, it’s not the end of the world so don’t worry. There are two places really where the noise could be coming from:
    1. The Head Unit
    2. Main Amplifier
    Let’s take a look at the sub’s head unit. The head unit is essentially an amplifier so if it has something broken it sends the signal to the main amplifier and the noise becomes even louder and the noise starts. So you either have a problem with your head unit or main amplifier 

How do you identify the problem?

The first thing you want to do is to get yourself one of these RCA to a Phone cable (3.5mm is recommended). You then take your source (Like your phone or anything like that), plug it into your amplifier using that cable, and then see if the noise is still there. If the noise is still there your main amplifier is broken. If it’s not then the chances are the problem is with your head unit. 

How to replace the Amp?

The best solution is to buy a new amp and replace the old one. Here is some good subwoofer Amp that will last long (https://amzn.to/2Qg80k6). You can talk to any technician to replace it for you or you can try following to replace it easily.

Steps :

   1. So first you want to Unscrew the back hood and don’t forget to drain the capacitor so you don’t get shocked.
   2. Now Take out the plastic trim unsealing the sub box which will reveal more screw so unscrew them too. (Be careful not to overstretch short wire)
   3. Here Take out the driver carefully and take a look inside the subwoofer box. Then with both hands gently pop out the amp. Don’t be hasty here since you could create a lot of damage.
   4. Finally, you want to take the new Amp and set it up just like the previous one was set up. It is recommended if you take the help of a technician if you are inexperienced. (Be careful while wiring the machine and don’t make any mistakes in internal circuits.) 

This method is extremely fast and guarantees results. So if money is not your problem replacement is highly recommended also you should of course take the help of an electrician during replacement if you are feeling nervous. 

DIY Method and Setup

So you want to fix the amp yourself right? There is a nice DIY hack you can do with a simple wire that works like magic. You will spend ‘Zero’, yes close to zero dollars in this method. But before attempting this be sure to have basic knowledge and necessary equipment for safety.
    The Setup is very easy. You need something like a phone, a good wire and you have modified your subwoofer. So what you need is the Head Unit (The thing that sends a signal to the main Amp), The Main Amp and the Subwoofer Sound Box. Now you want to connect it properly and make sure it is working properly. (The Noise Problem will still be there, so don’t worry). Now as stated above identify if it’s the Main Amplifier or the Head Unit that is causing the problem and take necessary steps.    

Fixing Subwoofer Making Noise without Input: Broken Head Unit

Now first put your subwoofer’s amp, head units and the driver on a nice bench. Be sure everything is connected and your subwoofer is working correctly/ Be careful with electronics since it is risky to work with those. If you follow the necessary steps correctly then you will get your result.

Steps:

     1. Take any piece of wire. 2 to 3 millimetre is preferred.
     2. Then strip quite a large amount of wire from the sheathing using a plier.
     3. Take out the RCA port from the back of your head unit
     4. Now what you want to do is to twist the stripped part of the previous wire so it stays altogether.
     5. Here you twist the stripped part in a figure of eight around the port demonstrated in the picture below. Be sure that it doesn’t come apart.

     6. Then when you plug in the RCA port make sure it (the wire) is clamped to the shielding.
     7. And now put the end of the sheathed part anywhere into the body of your head unit.

And Hopefully, your subwoofer will stop being noisy.

Fixing Subwoofer Making Noise without Input: Broken Main Amplifier

If you find out your main amplifier is the culprit, all you need to do is repeat the same thing. Be sure to have the same setup. But this time with the main amplifier.
    Step 1: Do the same thing with the wire and wrap it around the port of the Main Amplifier in the same fashion.
    Step 2: Now put the other end in the ground terminal.
    The steps are illustrated below in the picture

Be cautious and make sure that the apparatus doesn’t fall off like a house of cards. Also, it is noted that changing the amplifier is still recommended over this DIY fix.   

Fixing Subwoofer Making Noise without Input: Trouble Shooting the Amp itself

Nine times out of Ten the cheap method will work but If for some reason you can’t do the previous method there is one other rather hard but effective way. Let’s say you can’t get your head unit out, in a situation like that. So you want to go straight into the Amplifier and fix the grounding issue right there. But before you proceed, let me remind you this is no method for beginners, if you are not fairly confident with electronics don’t try this. But this is actually quite simple.

Steps :

     1. First thing you want to do is to disconnect it fully from the power supply.
     2. Now you wait for 10-15 minute because of the rail voltage.
     3. Then unscrew your amp and open it up
     4. Now use a multimeter to work out which pin in the RCA cable goes from the shielding to the cable.
     5. Now sever the connection and reconnect it to the Earth Terminal

Please note, this method is extremely risky, if you are not sure and confident in electronics do not attempt it. Replacing the amp is a way better solution instead.

Other Problems and Solutions if Subwoofer makes noise without Input 

Amp is the most common problem, but that doesn’t mean there can be some other trivial problem. You may have a problem with the power outlet or maybe the connection itself is broken somehow. However don’t worry, I’ll provide a solution to most of the trivial issues. You can follow some of this solution

  1. Try plugging the subwoofer into a different power outlet in your home? If it hums only when plugged into some of the outlets, the subwoofer is fine. So that means your wall power is faulty so check that.
  2. Try opening the Amp and see if the Capacitors are budging or exploded. Also, see if anything is burnt. Try fixing those issues.
  3. You want to double-check the wiring of the sub, sometimes that causes a lot of problem like this. Fixing wrong wiring is trivial and can be done by any technician.
  4. Try to find out if something is wrong with the receiver. If it is replace it asap.
  5. Use an AC adapter that allows three-pronged plugs to connect to a two-pronged outlet. It may solve ‘the ground loop problem’ if it exists.
  6. Try buying better subwoofer cables if yours are in a bad condition or are too old.
  7. Double-check your input settings.
  8. Maybe the issue is with your power supply. One solution is to ground it. First connect one side of a wire to the metal chassis screw of your subwoofer and the other one to something metallic, like a metal pipe. 

 Conclusion

The humming noise from the subwoofer is very irritating. It’s a common problem and can easily be solved if you follow the necessary steps. The Best thing is even if you can’t afford a new Amp you can try fixing the Subwoofer yourself via the DIY method for free. So if your subwoofer is making noise without input no need to worry about it since it can absolutely be fixed.

FAQ

Question: What is the most reliable method?

Answer: The most reliable method is to replace the Amp with a new one.

Question: Is Amp the only reason for the Problem?

Answer: Nine times out of Ten it is. Otherwise, it may be some trivial issue like a power outlet problem

Question: Should I hire an Electrician for it?

Answer: While an Electrician isn’t needed, you should definitely hire one if you feel like it

Question: Is it safe?

Answer: Yes it is. Apart from the “Fixing Subwoofer Making Noise without Input: Trouble Shooting the Amp itself” 

Question: What are some safety tips?

Answer: While working with Electronics, wear a rubber sandal and don’t touch anything with your wet hand. Don’t work while the sub is connected to power. To be extra sure, have someone by your side who will help you if something bad happens.

Question: Where do I buy a good Amp?

Answer: On Amazon, you can buy one for $200-$220. Here are some recommended by me.

Question: My Subwoofer is still having problems after following these steps, what to do?

Answer: If all fails, consider contacting your subwoofer manufacturer. They will help you troubleshoot it.

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