If you are having problems with your subwoofer such as a lack of sound or a distorted sound, you are likely to have a damaged subwoofer. Two of the most common culprits for this issue are with the voice coil or the speaker cone.
To determine the exact cause of problem and even to confirm if your car’s subwoofer has really blown, you can take the following steps.
Problems with you subwoofer can be related to the wiring and connection to the subwoofer itself. Since subwoofers cause a lot of vibrations, it is easy for a cable to disconnect from the speaker. We recommend testing the connection to the subwoofer before deciding to replace your car’s subwoofer.
Testing the Amplifier
The first test we recommend is testing the amplifier for sound output. If you have a problem with your amplifier or head unit, you will not get optimal sound from your subwoofer.
To test the amplifier, we recommend wearing rubber gloves for your safety. You will also need a multimeter for this test. Simply disconnect the positive and negative terminals from the subwoofer. Play music from your car stereo, and check for voltage on the multimeter. You should experience a fluctuating voltage when the amplifier is working correctly.
Testing the Subwoofer
If your amplifier is working as you would expect, then you should test the subwoofer for electrical functionality. Keep in mind, even if your subwoofer passes this test, you might still have a blown subwoofer. This test is simply to determine if the subwoofer will accept and use electricity as intended.
In order to test the subwoofer, you first need to disconnect the wires from the subwoofer that would connect to your amplifier. If you have speaker wire laying around, use the speaker wire to connect the speaker to a 9-volt battery. If you do not have speaker wire laying around, you can use the wire that would connect the subwoofer to the amplifier.
Note: It can be hard to attach speaker wire to a 9volt battery. We recommend using electrical tape to tape the ends on the terminals of the battery or purchasing a 9-volt battery connector.
After you have connected the speaker to the battery, you should see the cone of the battery move upwards (in some rare cases, the cone can move inwards, but it shows that the subwoofer is indeed working). Try disconnecting the battery and reconnecting it a couple times to see if the cone moves.
Here is a video that explains the process of testing electrical function of a subwoofer.
Checking the Subwoofer’s Sound
Ultimately, if there is something wrong with your subwoofer, you will notice the sound difference. You should test the sound to determine if there is a voice issue with the subwoofer.
We recommend using a bass Youtube video at a certain frequency and playing that through your audio system to test the subwoofer. To start, set the volume to the lowest level, and increase it slightly, while listening to the frequency response of the subwoofer. Do not turn the subwoofer above the medium volume level in this test, as that can cause distortion even on a fully-functioning car speaker.
If you notice a distorting voice while testing at different sound levels, the subwoofer may have blown partially and will need to be replaced soon. If you hear a cracking voice, then you have definitely blown the subwoofer. A cracking voice is a sure sign of blown subwoofer.
If your subwoofer doesn’t have the same quality as it once did, there’s a couple things to check to make sure that the subwoofer is blown. If you have found that the subwoofer is blown, we recommend checking out our guide to the best subwoofers.