Updated at: 30-08-2022 - By: Lucas

It’s safe to say that a subwoofer makes a big difference in the sound quality of any type of music. As long as the neighbors don’t mind the noise, a custom audio setup is an easy way to transform any place into a party.

But if you find that the subwoofer isn’t working, you’ll need to find out why. There’s a strong indication that the amplifier is functioning, but we can’t yet rule it out. When troubleshooting an electrical issue, it’s critical to eliminate all possible causes, no matter how innocuous they may seem at first. In this tutorial, I’ll show you how some components look to be operating, but in fact aren’t.

For easy reference, below are the most common causes of a subwoofer problem.

Faulty fuses; low voltage; wrong impedance; incorrect amplifier; and a faulty subwoofer.

Subwoofer Is Not Working – Troubleshooting Steps

subwoofer not working amp has power

A multimeter is all you’ll need to correctly diagnose subwoofer issues. If you’re looking for an accurate way to measure voltage and impedance, then this is the tool for the job.

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Make Sure the Sub and the Amp are Grounded

A subwoofer and amplifier’s ground should always be checked first, regardless of whether they’re stock or a newly fitted subwoofer.

If the subwoofer is not grounded, it will make a hissing or humming noise, and it could also harm the sub and the amplifier.

Disconnect the battery’s ground terminal first to see if the connection has been tripped. You can use a multimeter by touching the two test leads and measuring their resistance. To improve precision, any measurement should be multiplied by a negative number.

Connect the ground lead to the battery’s detached ground wire. The amp and subwoofer are positioned in the back of the vehicle, so you may require extension lead wires to get to them.

Probe the grounding points of your amplifier and subwoofer with the live lead. Using the base of your seat belt clasp or a cargo strap anchor may result in a high reading. Your ground should have the lowest possible reading. If you’re interested in learning more about grounding, you may do so by reading this article.

Check The Fuses

Inside of the fusebox, you’ll find wires and connections for the car’s many systems. Even though you’ve undoubtedly already checked the fuses, simply looking at them from the top won’t tell you whether or not they’re bad. You can use a multimeter to speed up the procedure or pull out each fuse one at a time to see if the metal wire flowing through them has snapped.

As your ground, connect the multimeter’s black wire to the COM setting when first setting it up. The red wire is the active one, and it should be plugged into the multimeter’s other slot, which will include markings such as V, mA, or (Ohm). Alternatively, if you’re using the multimeter I linked, just set the dial to and it will automatically adjust.

Exposed metal on the fuse should be contacted by two test leads. If you get a reading on the multimeter, that means the fuse is functioning properly. Pull the fuse and install a new one if you can’t get a reading. Fuse extractor included in this kit makes it easy to remove fuses without harming them, making it a must-have for any car owner.

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There are generally a couple of fuses on the back of the amplifier, which you may not be aware of. Check them out, since they could be the source of your audio issues.

Take a look at the following video, which explains the measuring process in greater detail if you’re still unsure of what to do.

Measure the Voltage

If you don’t supply enough electricity to your amplifier and subwoofer, they won’t work properly The subwoofer requires 12 volts from the battery, while the amp requires 10. 5 16. 5 volts from the battery. Voltage fluctuation directly impacts sound power in unregulated amplifier configurations, but regulated amplifiers don’t have this issue.

It is possible that you wrongly concluded that the amplifier was working based on the signal light being on, but the light can be on even if the voltage is significantly lower than necessary. To accurately measure voltage, you’ll want to use a stereo system with a single frequency of sound to ensure that the voltage remains constant throughout the measurement. You can play this on your phone if you want to link it.

Use the red lead on the live terminal and the black lead on the ground to check the battery voltage reading with the V (voltage) setting on the multimeter. Make a note of anything you read for later use. Now, take a voltage meter and measure across the amplifier’s terminals.

A battery-to-terminal voltage difference of more than 0.5 volts is cause for alarm, but anything less is OK. The subwoofer can be tested in the same way, to verify if it obtains the 12 volts it need to work properly.

If you see a dip in voltage, you’ll need to locate the source of the problem. In most cases, this is caused by a power line flowing to the amplifier or subwoofer, but the following video explains this in great detail.

Improperly Connected Subwoofer Wires

Remember the last time you bought furniture from Ikea and didn’t read the instructions because it was so obvious? Positive and negative wires can be found on both sides of a speaker’s connection to an amplifier. That’s not quite right.

If you’re working with a four-channel setup with four speakers, everything is rather basic. Right and left, as well as positive and negative, are clearly defined on both rows of speaker outputs on this motherboard. Because of this, it is necessary to build an additional bridged connection when using a subwoofer.

To connect a subwoofer to a two-speaker system with one subwoofer, connect the positive of the left side and the negative of the right side to the bridge outputs on the bottom row. One speaker is located on each side of the top row. At the bottom of this bridge, you pair the left and right speakers and connect them two at a time to form a four speaker and one subwoofer arrangement.

It’s easy to find your amp’s handbook online, and using it can stop you from having sound troubles or even overloading the amp. The next video will show you how to wire your speakers and subwoofers correctly.

Check Your Settings

Perhaps the subwoofer isn’t receiving any sound from the head unit. Make sure everything is set up correctly by consulting the instructions and tinkering about with the settings. So make sure to read this post to learn more about speaker-related concerns.

Bad Amplifier or Subwoofer

It’s possible that the amplifier or subwoofer isn’t working if you’ve reached this stage in the instruction without finding a solution.

A failure could have occurred even if the amp was previously working properly but the subwoofer was mistakenly installed. Alternatively, the subwoofer may have been defective when it was shipped from the manufacturer and will need to be replaced.

How To Buy The Right Subwoofer

Subwoofer Not Working Amp Has Power

Subwoofer Size

A subwoofer must have the optimum amount of air volume in order to work properly. Just because you can squeeze an enormous woofer into a small enclosure doesn’t mean you can get away with doing so. The subwoofer specification sheet will provide this information, so check it out to see if it fits in your desired mounting location.

Voice Coils

Single- and double-voice coil subwoofers are two common configurations. To connect your subwoofer, you’ll need to use both of its voice coil connection ports, if it has two. Installing several subwoofers and matching the amplifier’s impedance are both easier with a single voice coil system, but dual arrangements provide you more flexibility.

Power Rating

A subwoofer’s RMS constant power rating is far more relevant than its maximum power rating. The RMS continuous power rating of your amplifier must be the same as the RMS continuous power rating of your speaker.

If you have four subwoofers each delivering 300W RMS, you’ll need an amplifier capable of delivering 1200W. With a subwoofer that is underpowered, the amp will limit its maximum power output.

Vented or Sealed Box

Using the EBP calculation, you may determine if the subwoofer needs a vented or sealed enclosure (Efficiency Bandwidth Product). You may find the Free Air Resonance (Fs) and Electrical Q (Qes) values in the product’s specifications.

Near to or over 100 suggests that the subwoofer is more suited for an open box, while values close to or below 50 indicate that the subwoofer is better fitted for a closed box. You have a choice between the 50 and the 100 box. There are no hard and fast rules here, but following these suggestions should improve the performance of your subwoofer.


How long should a subwoofer last?

If properly cared for, subwoofers can survive for decades. Physical damage and a short circuit caused by water or other liquids are the two most common ways to shorten the life of a subwoofer. Damage to the subwoofer might also result from failing to clean it properly.

How do you tell if a fuse is blown?

With a multimeter, you may verify the circuit between the fuse’s two ends. Without one, you can pull out the fuse and peek through the plastic at the central wire. In a good fusion, the shape will be a and it will be clean looking. The connection will break if the fuse fails, and the plastic and metal will become discolored as a result of heat damage.


To fix subwoofer issues, time and dedication are required. You should take your time, check every fuse, and measure the ground resistance twice to make sure it’s safe. A professional electrician or car stereo firm may be able to help you if you can’t figure out what’s wrong with your car stereo after following this guide’s instructions.