Why Does My Car Stereo Make A Buzzing, Humming or Hissing Sound?

Car stereo

A new car stereo or accessory can take your in-car music experience to the next level. However, it is common to deal with problems with your audio system at times.

One of the problems that car owners complain about is the noise coming from the stereo. Noise can come in different forms and from various sources.

In this post, we discuss why your car stereo makes a buzzing sound. We talk about the causes of this noise problem and some simple fixes for the issue.

Read on to find out how you can quickly get rid of the buzzing noise in your audio system.

Common Causes of Buzzing Sound from Car Stereo

A buzzing sound coming from your car speakers can be associated with several issues. Different components of the audio system work together to deliver a smooth, distortion-free music experience through the car stereo.

If your radio makes a buzzing sound, you should evaluate different aspects to identify the cause. Here are some of the most common considerations for the car stereo and the possible solutions.

Receiver Grounding

One of the biggest causes of noise in your audio system is improper grounding. Check whether the ground wire is connected properly to the vehicle’s ground.

You should also see if the ground wire is somewhere near a source of noise like an air conditioner or heater.

An antenna lead is often the source of noise in a receiver because it acts as a ground to allow the head unit to function without connecting the ground wire.


See if you hear the noise from all the sources of sound, FM, AM, USB, and CD. If the noise comes only from the radio, it should be due to the antenna lead.

Try disconnecting the antenna to see if the noise disappears. In this case, you can use a noise suppressor for the antenna. Such a filter breaks the ground connection between the antenna and the radio to prevent the noise from entering the audio system.

Radiated Noise

If the buzzing sound doesn’t come from the antenna, you can try pulling out the receiver from the dashboard while playing a CD.

The noise should be caused due to the receiver’s close location to a noise source like a computer or heater. You can use a noise filter if the component works on a motor. You can even use a magnetic shield foil to prevent the noise from entering the system.

Why Does My Car Stereo Make A Buzzing Sound?

Is Your Amplifier Itself Causing Humming or Buzzing?

Your new amp can often be the cause of a noise in the car stereo due to improper mounting or poor ground. You can use rubber feet or grommets to isolate the amp from the chassis.

If nothing works, you can use a noise suppressor. It can be a little tricky to find out what works. Try these tests for your amplifier before addressing the problem.

A ground loop Isolator will generally fix common ground loop issues in most aftermarket amplified systems. Check them out here and give one a try.

Check the ground wire

See if the ground wire is attached securely to the chassis and has good contact with metal. The wire should be 18 inches or lesser in length. A too-long wire can cause noise issues. Most noise problems originate from improper grounding.

Location of the amp

If your amp is placed somewhere near a component that radiates noise like a computer or tuner, you can unbolt and move it to another location and check if the noise disappears. Try removing the patch cables.

If the noise persists, you can check if the amp is isolated from the chassis of the car. Contact between the amp’s casing and the car’s body can cause noise.

Check the gain structure

If your audio system has an external amplifier installed, you can get rid of system noise by checking with the engine off. Insert a disc and pause the player.

Keep the volume low and listen before increasing the volume to high. Then play the music and see if you can hear the buzzing sound. You can solve this problem by reducing the gain of your amp.

Can RCA Wires Cause Stereo to Make Noise?

Can RCA Wires Cause Stereo Noise?

Another cause of buzzing sound coming from the car stereo can be the RCA cables connecting the components together. Test for this problem by disconnecting these cables from the amplifier.

Try inserting one end of a spare cable into the amp’s input jacks and turn on the audio system. If you don’t hear the noise, it means it is not because of the cables.

If the sound is audible, your cables are picking it up. You can try separating the cables by a distance of about 18 inches.
You can even try replacing the RCA cables with superior quality because cheap cables often don’t have the insulation to prevent noise.

The amount of noise your cables pick depends on the loop area. Bigger the loop area, the higher chances your cable has for interference. You can go for a twisted pair cable to get rid of this issue.

This will ensure a small loop area and ultimately lesser noise. The last option is to install a ground loop isolator between the amp and the preamp outputs.

Why Does My Car Stereo Make A Buzzing Sound

Power or Ground Wires Causing Noise in Your Car Stereo?

If the buzzing sound is not due to the antenna cable or poor grounding, it can be through the main power cable of the amplifier. A cable with an insufficient gauge can create noise so you can try using a thicker cable instead.

The presence of multiple amps in the audio system can also create ground loop problems that you can easily resolve by grounding the amplifiers with separate wires for each. If you don’t understand the cause, you can consider installing a ground loop isolator to minimize the issue.

Speaker Wire Causing Buzzing or Humming?

A buzzing sound coming from your car stereo can be from the speaker wires as well. To test for this issue, switch the system off and disconnect the amplifier from the speaker wires. Start the car and check if you can hear the noise.

If yes, it is radiated through the wires that you can consider repositioning. You can even shield the wire by wrapping with a metal foil.

A buzzing sound coming from your car stereo can be frustrating, particularly when you are waiting to listen to your new equipment.

However, such problems are quite common and indicate that something is out of order. You can use the tests listed in this post and try eliminating each of the possible causes until you find the source of the problem.

Frequently Asked Questions

Does the quality of my Wiring make a difference?

Yes, the quality of your wiring can determine how long the wiring will last and it can in many ways determine the quality of the signal in carries in or out of an audio source.

Why does my car stereo make a buzzing sound when I accelerate?

This is commonly caused by a bad ground to your aftermarket amplifier. We find that customers don’t have the right size wiring for power and/or ground.

Make sure they are an adequate gauge for your amplifier and that they are both the same size. If they are the proper size, inspect the location where you screwed in the ground.

If you find that the screw is loose or the ground location is more than 18 inches from the amplifier (more than 18 inches long) this will not suffice.

Verify your amplifier is mounted properly. mounting an amp to a metal surface without something in between the amp and the chassis can cause grounding issues.

Why does my stereo make a hiss noise when I Plug in My Phone?

Commonly caused by a ground loop if your phone is plugged in via 3.5 mm headphone jack and USB for charging. Installing a ground loop isolator should fix this.