Amp Has Power But No Sound From Subwoofer [How to Fix]

A car amplifier’s main job is to provide that extra power your subwoofers need to create bass and better sound quality. If your car amp has power but no sound from the subwoofer, the speaker or subwoofer will not play bass, and you will not enjoy the sound coming from it.

Your amp may power-up, but you still get no sound from the sub. In this case, you need to watch out for two problems; subwoofer control on the stereo has been turned all the way down, or you’re using a bad RCA cable.

If your amp powers on but no sound comes from the sub, do not quickly assume that the amp is blown out or faulty. Instead, read on and learn how to find the problem and fix it to save yourself the trouble of seeing the amp technician or buying a new amp that you might not need. Learn how to troubleshoot this problem and fix it.

Fixing an Amp Has Power But No Sound From Subwoofer

Troubleshooting an Amp that has Power but No Sound from the Subwoofer

Several people have been in a situation where their car amp turns on but no sound from subs. While this can be frustrating, there are several steps that you can take to troubleshoot and fix this problem like a pro.

1. Check the Amp’s Input and Output

If the car amp has power but not sound in the amps, you can check its input connected to the head unit. Check the RCA cables that connect the amp to the head unit. If your stereo has several RCA outputs, ensure that you check all of them, one after the other, while testing if you can get any sound from the sub.

The RCA cables provide the amp with signals for the stereo. Therefore, if they are disconnected or plugged in the wrong ports, the amp will power up but will not play. If the RCA cable is okay, the problem might be lying in the head unit and not the amp.

Just to be sure, you can use a 3.5mm-to-RCA adapter and plug it one end in the amp and the other end into your phone, then play some music. If there is sound from the subwoofers, then the subs and amp are okay, and you should check the head unit for malfunctions.

Checking the amp’s output is easy, and all you need to have is another subwoofer. To test your amp, hook the test sub to all the channels in your amp one after the other. This should reveal any issues with the output.

To fix a problem with the cables, inspect them visually. Assess them for damages, being careful not to touch them before you turn off the power. Check the wire with a multimeter to confirm if it shows any voltage. Replace damaged cables with new ones and see if you can get some sound from your subs.

Check the Power of Your Amplifier
Check the Power of Your Amplifier

2. Check the Power of Your Amplifier

It is important to note that your amp might still turn on even if it doesn’t receive the amount of voltage or power it needs to operate. When the amp receives less voltage, it will look like it is working, but the subs will not receive any signal from it.

To troubleshoot this, check the voltage on your amp’s negative and positive terminals using a voltmeter. Check if the reading is between 12 to 14 volts. This is the correct reading for a properly working amplifier. If the voltmeter reads anything low than 12 volts, you could be dealing with a low voltage problem.

Check the battery connections, ground and power wires at the fuse block, grounding bolt, and any other point that can get loose in the power system. A poor connection in the grounding wire will cause it not to work as it should. If your amplifier has built-in fuse switches, remove them from the amp and check their continuity. If the fuse is okay, it will give an almost zero ohms reading on your multimeter.

If the fuse is blown, you should consider replacing it with the right fuse for your amp because the wrong one can damage it. In case the new fuse blows out after installing it, you could be dealing with a wiring problem. Always remember to turn off the electrical system before removing or installing a fuse.

When troubleshooting your amps power system, you should ensure that you check:

  • The remote wires: These wires come from the radio, and they play an essential role in your sound system. If they are faulty or wired incorrectly, they will not give the subs the right output, resulting in no sound.
  • The power wire: Damaged or shortened power wires cannot supply enough current to the amp.
  • Impedance mismatching: When your sub mismatches your amp, it can produce an annoying or distorted sound because of under or overpower the amp.

3. Check if The Subwoofer is Short-Circuited

This is one of the most common causes of subwoofers and speaker problems. If there is any metallic object touching the negative and positive rods at the terminal and cone of the sub, it will instantly short out the system.

Short-circuiting is a hard-to-detect issue. You’ll only see it once you turn on the amp, but you don’t get any sound from the sub. To rule out a short circuit, try connecting your sub with another amp. If there is still not sound, it may indicate that the wires are burned, and no electrical signal is being conveyed to the sub.

4. Check the Electromagnetic Coil and the Cone Seal of Your Sub

If your amp turns on but no sounds from subs, you should also check the sub’s electromagnetic coil and cone seal. This is one of the most delicate and comprehensive tests that you may have to perform.

Start by opening up the sub. Once you get access to the inner components, inspect how the cone is connected to the enclosure. Your sub’s cone is in charge of giving the last audio output. It moves back and forth and, in turn, pushes and pulls air. If the seal is broken or loose, it will not be able to move as it should and will not produce sound.

If the sub’s electromagnetic coil is burnt or out of place, it will not create a powerful electromagnetic field needed to work together with the magnet the sub needs to produce sound.

Also Read: 10-Inch vs. 12-Inch Subwoofer: Which Should You Go For?

Final Word

Everyone loves good music while driving. However, all music equipment (even from the most reliable manufacturer) is prone to malfunction. If your amp turns on but no sound from speakers, it could indicate a load of problems that you’re ready or not ready for. That is why we urge you to seek expert help, especially if you’re new to car audio.

Avatar for Jamie K. Martin

Jamie K. Martin holds a degree in Audio engineering from Husson University, Bangor. Martin spends most of his time testing and trying the technology he writes about to ensure that he provides first-hand information to our customers from all walks of life.

2 thoughts on “Amp Has Power But No Sound From Subwoofer [How to Fix]”

  1. This has been very informative and helpful, thank you. I had my amp bench tested and it was fine, I hook it up and nothing but a static noise coming through the test speaker I’ll check the input gain levels as this may be the case.


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