In recent years, subwoofer has become an integral part of a home theater system, with its impactful bass and deep cataclysm rumble. It makes watching a movie at home so much more exhilarating and brings you closer to a true cinematic experience. And it is not just the movies. With the bass supplement of a sub, it is also exciting to watch live concerts at home, you can feel the atmosphere like you were there.
Great for music as well, not just bass-intensive tracks but also for music that uses a pipe organ as an instrument. They can go really low, subterranean level of low to be more accurate, some organs with 64′ pipes can reproduce sound at 8 Hz! As you can see, a subwoofer is a powerful speaker, and at times, you may hear unwanted noises such as rattling. Don’t be alarmed when you hear rattling noises, as this might not mean there is something loose inside your beloved subwoofer. And so this article regarding how to fix a subwoofer that is rattling will provide you with the usual causes and fixes.
How does a subwoofer work?
Before we continue, you should at least know the various components of a sub and how they work. This information may come in handy as it can give you a clearer picture later on. These are the essential components of a typical subwoofer; Amplifier, Backplate, Cone, Voice Coil, Spider, Surround.
These subwoofer components work cohesively together, and here’s a summary of the process. Amplifier turns sound waves into sine waves of AC current then the AC current changes the voltage to either positive or negative value. If the amplifier creates a positive voltage for the subwoofer, it will move the sub’s voice coil and cone forward. If it is a negative voltage it will move the sub’s voice coil and cone backward. How far they move is depended on the voltage value. These movements enable the subwoofer to push air and reproduce low-frequency sound.
As you can already tell what will happen at bass intensive movie scene, the subwoofer is going to ‘move’ a lot.
What causes subwoofer rattling
We are going to look at the various common causes of subwoofer rattling, and do note that there are times the rattling noises are not directly from the sub itself. Please start by using the exact same movie scene or music that will cause the rattling noise for troubleshooting purposes.
The amount of bass that subwoofer produce can also create vibrations that will rattle wooden cabinets such as wardrobes, bookshelves, wooden box, etc. You can start with cabinets in near proximity to the sub. If you found one, you can try covering them with a rug or materials that can dampen the sound. For instance, one of my cabinet doors is vibrating and making a rattling noise, I’ve used a thick towel covering both outside and inside of the cabinet door. The drawback to this is that the door will be slightly ajar because my towel is between the gap. It worked but it looks weird. Another way is to move your subwoofer away but may affect your bass performance if you have already done your subwoofer crawl, calibration, etc.
The bass vibrates your cabinets or shelves which transfer the vibrations into the small objects then causing them to vibrate/rattle. Usually, this will happen to small objects that are light in weight, and if possible just remove the small objects that are making the rattling noise. You can also relocate your heavy subwoofer, but I think it is still easier to move the lighter and smaller offending objects.
Remove Objects from the top of your Subwoofer
Sometimes a subwoofer doesn’t need any decorations and it will still look good. If you insist to place decorative objects on the top of your sub, then maybe these objects may produce rattling noise. If that happens, you can just simply remove them.
Floor making the rattling noise
The powerful vibration from your subwoofer is causing your floor to create rattling noise, this usually happens with wooden floors. There are a few ways to solve this, you can either carpet the whole room floor or at least place your subwoofer on a carpet. You can decouple your sub from the floor using Subwoofer Isolation Stand. Combining both methods may provide even better results.
Loosen Subwoofer Feet
Sometimes the subwoofer feet may have loosened, and causing an unnecessary rattling noise. You can check them one by one, and if you find one, just tighten them up.
You should check for loose cable connections as they may rattle if they are not fastened properly. You may also want to take this opportunity to find any damaged connection points.
Your subwoofer is Overpowered
Sounds like a good thing but it is not, as every subwoofer has their own limit and when it exceeds the amount of power they can handle, it will either damage the subwoofer or reproduce distorted sounds or both. For instance, if the positive voltage signal is too high, it will cause the cone to move forward beyond its limit thus damaging the cone. And if the negative voltage signal is too high, it will move the coil backward till it hits the backplate. Sometimes the damage is so great that the voice coil/cone is torn.
Even though is not common but you’ll just need to be careful when driving your subwoofer.
Your subwoofer is Underpowered
Sadly, this happens more often than it should be. If you like to drive your subwoofer hard and play movies at loud volume, you need to be cautious especially if your subwoofer amplifier is not powerful enough (underpowered) to handle them. An underpowered amplifier will produce clip signals which cause distorted sounds and even rattling noises. This will also badly damage your subwoofer either in the long run or at an instant.
The only solution is to use your subwoofer moderately or maybe is time to get a more powerful subwoofer.
Subwoofer Grille Cover
After using the subwoofer for a while, the screws of the grille may have come loose due to all the high octane action movies you have been watching thus creating the rattling noise. A simple fix will be to tighten the screws or just remove the whole cover.
Faulty Amplifier and Loose Parts within the Sub
If you have gone through all the above, and the rattling noise still persists. Then there’s a probability there are loose components in the subwoofer due to wear and tear. It can be another issue such as a faulty amplifier. I will suggest that you send the subwoofer to your dealer or technician for repair. You can check with them on the potential costs and decide if is worth the money.
There are plenty of potential causes and most of them can be solved by yourself. This is why you should always spend some time on basic troubleshooting first, not only saves you the trouble of carrying your subwoofer all the way to the repair shop and be told there is nothing wrong with it. You also might save some money. How long your subwoofer can last is usually depended on you. If you want more bass output to fill the room, I will recommend getting a second subwoofer either connecting it directly to your AVR or daisy chain with your first subwoofer.