How to Tell if Subwoofer is Blown

A subwoofer is a very important part of any audio system as it is necessary to create a full-range sound. Neither a cheap and small sub nor the best 10-inch subwoofer is immune to damage to internal components for dozens of different reasons. As a result, if you detect a noticeable loss of bass in your system, you may start to suspect that your sub is blown.

How do I know if my subwoofer is blown, you might wonder? To begin, establish whether the problems with your speakers are related to the indications of a blown sub. To do so, you’ll need to run a few easy tests.

Signs of a Blown Subwoofer

Excessive power and distorted signal received by a subwoofer are two of the most common reasons for a blown subwoofer. The key signs are damaged cone, weak and deteriorated sound (or its absence), and improper voltage.

How to Check if the Subwoofer is Blown

Test the Cone

Detach the cover of your subwoofer, then push the cone on the left and right sides (don’t put too much effort when doing so). If it isn’t solid and moves strangely (it’s wobbly and unsteady), or doesn’t move at all, the cone is probably blown. You may also hear some scratching sounds while pushing it.

Test the Audio

A blown sub can be detected by the deteriorated sound quality. If you have noticed that the sound reproduced by your sub has become weak and distorted at all volume levels, it’s time to run some audio tests.

Gradually increase the loudness and bass from zero to maximum. If you notice distortion that you have never heard before, your speaker may be partially blown. If there’s no sound at all, this is a more serious sign. However, before blaming the subwoofer, you should also check if the cable and the sound source are working properly.

Test the Voltage

A multimeter is a useful tool for determining the amount of voltage present. So, how to check if a subwoofer is blown with a multimeter?

  1. Turn the sub off and disconnect it from all the sources.
  2. Remove the sub from its enclosure (if necessary).
  3. Connect positive and negative probes of the multimeter to the corresponding terminals of the sub.
  4. Set the multimeter to measure resistance.

The absence of voltage or its instability indicates that the cone is damaged. So, any value above 1.0 Ohms indicates that the coil is okay. If the reading on a multimeter is below this value or constantly changes, it’s a sign of a blown cone.

Conclusion

If your sub is partially damaged, you will most likely be able to cope with it for a minor expense: you will just have to fix the damaged part. It’s pointless to try to repair a totally blown subwoofer; in this situation, you’ll almost certainly have to buy a new one. 

So, now that you know how to tell if the subwoofer is blown, ensure to remove the damaged sub from your audio system if the tests have helped you detect that something is wrong. Otherwise, it may damage the rest of your gear.