Signs of a Blown Subwoofer | Causes | How to Fix

As we know, subwoofers are specialized forms of woofers. Subwoofers give an amazing sound for home theaters. Passionate music people added subwoofers to the sound system for better and clear sound. 

Speakers, woofers and subwoofers are technology things. These can at times fail to provide the clear sound that we want due to certain causes or due to our own mistakes. They can be blown partially or completely at various times. We will discuss the signs, causes and mistakes that contribute to a blown subwoofer. We will later discuss how to fix a blown subwoofer.

Signs of a Blown Subwoofers

A subwoofer is a crucial part of our sound system, as it allows us to hear clear and precise sound. However, sometimes when we turn on our sound system, the subwoofer is still in a working state, but it sounds so bad that we would not want to turn it on again. Sometimes, the subwoofer does not even work. It sometimes leads to a blown subwoofer. There are some signs that can help you to figure out whether your subwoofer is blown or not.

• No Sound:
• Distorted Sound
• Test cone Movement
• Test the resistance of the subwoofer.

No Sound

When you play music and you do not hear any sound, it is a sign that your subwoofer is maybe blown. But sometimes the case is different, what if your subwoofer does not produce sound and it is not blown at the same time. Maybe your subwoofer is safe.

You should also check if the audio signals are getting to your subwoofers since people sometimes assume that their subwoofers have failed when the signals are not getting to the subwoofers.

The subwoofers are receiving audio signals, but they are not producing any sound, now it is an indication that the subwoofer is damaged or blown.

Distorted Sound

Occasionally, the blown subwoofer still produces sound when we play music. There is a distortion in the sound, and you cannot hear any sound, and you may try to turn off the sound system or put your fingers in your ears. That type of noise is a clear sign of a blown subwoofer.

But sometimes the blown subwoofer works fine at low volume, but when we turn up the volume or play a higher bass sound, the subwoofer shows distortion.  

Test cone Movement

To test the cone movement of your subwoofer. First, you need to remove the cover to access the cone of your subwoofer. You now need to use both hands to press the cone downward, but be careful not to use too much force. If you hear scratching noises when you push down on the cone or it doesn’t move at all when you push down, then there is an indication that your subwoofer is blown.

Test the Resistance of Subwoofer

One of the easiest ways to check whether your subwoofer is blown is to test its resistance with a multimeter. If you are trying to determine the subwoofer’s resistance. You can check with a voltmeter whether your subwoofer is blown or not by following these steps.

1. The first thing you need to know is the impedance (Ω)ohm of your subwoofer, as subwoofers come with different impedances. 
2. Then you need a digital voltmeter.
3. Connect the positive lead to the positive and the negative lead to the negative.
4. To prevent damage to the cone of the subwoofer, make sure that nothing touches it. 
5. Make sure you are not in an environment where there is air that can cause the cone to move. 
6. Read the impedance on the digital voltmeter to see if it’s stable or close to the subwoofer impedance. (For example, your subwoofer impedance is 4 ohm, and the voltmeter shows approximately 3.6 or 3.8 ohms) which means your subwoofer is fine. 
7. When the impedance reading is deviating or not stable while reading and is half of the subwoofer impedance then that is a clear indication that your subwoofer has blown.

Causes of Blown Subwoofer

There can be many reasons why your subwoofer is blown. Subwoofers can be destroyed by thermal failure, mechanical failure, or physical things. Let’s discuss these things one by one, it will help you to understand what caused your subwoofer to blow.

1. Overpower
2. Distorted Signals
3. Drop or Physical Thing Hit

Overpower

The most common mistake that damages a subwoofer is overpowering. By overpowering, you are given more power than is required to drive your subwoofer.

Subwoofers each have a different RMS, and they cannot be operated as far beyond their limits as they are. That is why subwoofers come with amplifiers that control the power delivery so as to avoid supplying excess power that could damage the subwoofer.

When your subwoofer is continuously overpowered. Heat is produced by excess power, which cannot be released into the environment. Heat buildup causes the voice coil to heat up instead.

If the voice coil is overheated, the glue or adhesive that holds the coil to the former will soften, causing the coil to deform, and with more heat build-up, the coil will be completely damaged. When a voice coil is damaged, it ceases to work and the subwoofer is unable to produce sound.

Distorted Signals

Subwoofers can easily be damaged by distorted signals. Subwoofers can be severely damaged by distortion or clipping in the signal. Until the levels become high enough to cause distortion and damage, the signal can be distorted without you even being aware.

Drop or Physical Thing Hit

Subwoofers may be damaged by being dropped, or by being hit by a physical item, or by using too much force when checking the cone. A drop or physical blow to your subwoofer will often damage the cone.

Steps to take before fixing a subwoofer

When you realize all signs of a blown subwoofer have appeared, and you wish to have it repaired. Then you need to take the following steps.

1. You must first remove your blown subwoofer from your sound system. Your sound system will suffer damages if you leave this in place, causing bigger problems for you. 
2. If your subwoofer is blown, you should check the warranty on it. If the subwoofer is still under warranty, you’ll need to take it to the store for a replacement.
3. You should check the repairing cost if the subwoofer warranty period has expired. Often, the repair cost is greater than the actual cost of the subwoofer.
4. If the repair cost is greater than the actual cost of the subwoofer, then you do not need to repair it. Then you buy a subwoofer that has advanced technology and enjoy music.
5. If the repair price is less than the actual cost, you should bring the subwoofer to a professional. Professionals have tools and knowledge about subwoofers that we lack.
6. If the voice coils are blown, repair costs will be higher. There may not be spare parts readily available for these speakers, so you will have to purchase used speakers and remove the parts. Hiring professionals to do it for you can be expensive.