Car Amp Turns On But No Sound From Subs

Car Amp Turns On But No Sound From Subs

The car amp turns on, but no sound is coming out of subs.

This is one of the many problems you may face in your journey being a car audio enthusiast.

Car stereo systems are complex because they involve more than just one component. And oftentimes, failure of one component affects the performance of the other.

A car amplifier provides an amplified signal to your subwoofer. The sub then converts this signal into the sound we hear. But if there’s some problem with the amp, you may not hear anything at all.

This is different from a blown speaker where you do get low sound (albeit distorted).

Some people think that no sound from subs is due to the faulty or blown amp, but it’s not true and can be caused by various other reasons ranging from bad RCA cables to amp’s gain mismatch.

In this article, we’ll find different solutions to remove this issue.

Check Subwoofer Settings

Most aftermarket stereos have separate subwoofer controls in the settings, which we can accidentally turn off. So you should double-check to see if the sound output is turned on and the dB level is higher than 0.

Make sure Amp is mounted to a non-conductive surface.

After this, you also need to ensure that no part of the amplifier is in contact with any metal of the car. This can cause many issues, such as signal clipping and amp going into protected mode.

Check Amp’s Ground And Power settings

If an amp is not getting the required power from the system (in the first place), it won’t amplify audio signals. You can use a voltmeter to check your system is providing the necessary power to the amp.

To do so, connect the voltmeter to the positive and negative terminals of the amp. You should get 12V reading with the engine off and 14V with it being on.

If that is not the case, you should inspect the power and ground wires to make sure they’re not loose at any point.

Remote Wire Fault

The car amplifiers come with a turn-on wire (also called remote wire) used by the head unit to signal the amp to turn on – usually when you turn on the vehicle. It is usually a blue wire with a white stripe (not to be confused by a solid blue wire for power antenna – dedicated to radio only).

To test it, turn your head unit to a source other than radio, and check the voltage between the amp’s remote turn on terminals and the ground through a voltmeter. If it’s roughly 12V, then there’s no problem.

But if it’s not, change the source back to the radio and see if if you get any reading. If you do, then you only have the power antenna wire connected instead of the remote wire.

If there’s no voltage with any source (including radio), then there is an issue with your turn on wire.

Make sure amp is receiving music input signals

Next, you need to ensure that your amp receives the music signals – through speaker level inputs (high-level inputs) or RCA level inputs (low-level inputs).

Disconnect the RCA cables, connect with your head unit through a new pair, and turn the head unit on – with volume up. If it’s working with new RCA cables, then it means the older pair was at fault.

If only one of them is working, the problem is with the head unit – not the amp.

Check if the amplifier is outputting signals

Lastly, we’ll check the speaker outputs.

Disconnect the amp terminals from the speakers and connect them with another testing speaker – one channel at a time. If the amp is fine on all these channels, it means your speakers are faulty. This can be due to speaker wiring or a bad connection.

On the other hand, if there’s no output from the test speakers, it means the amp is faulty.


Alright. So these were some of the most common reasons why you’re getting no sound from subs despite your amplifier turning on.

As I said, there can be various reasons why you’re experience it. But if you’ve followed all the steps above, I’m sure you’ll find the root cause.

In case you’ve experienced any other issue that caused no sound from your sub, make sure to let me below in comments.

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