You’ve upgraded your car audio setup with a new amp and subwoofer. And are now jamming your favorite soundtracks while cruising on the road.
But as soon as you accelerate, a whining noise starts coming from the sound.
This noise is not unbearable, but you understandably want to eliminate it, having spent so much on the aftermarket components.
From what I have seen, it mostly happens due to ground loop, alternator interference, grounding issues with the head unit or the amplifier, unshielded RCA cables, etc.
In this post, we’ll discuss these issues in full detail.
9 Reasons Why Your Car Stereo Is Making Whining Noise
The ground loop is the most common reason for the whining noise coming from a car stereo.
It happens when multiple components of your car audio system are connected to different ground points, creating a loop that results in noise.
This noise can be in the form of a static and a whine that increases when you accelerate the vehicle.
Although there are many scenarios where you can have this issue, the common one is using the phone as a music source via a 3.5mm AUX cable while charging it through its other port.
The popular solutions for fixing this issue include a common grounding point or having a ground loop isolator in the AUX cable.
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Interference from the Alternator
If you notice the whining noise only when the engine RPM is going up, it indicates interference from the alternator.
The alternator is responsible for powering the radio and other accessories when the engine is running. As it produces AC current, the fluctuations in magnetic fields around it can induce a current in the nearby cables, including the car audio cables. This induced current can result in a whining noise.
Contrary to popular belief, this noise doesn’t mean anything is wrong with the alternator. All you need to fix is to ensure that the alternator is grounded correctly, have a noise filter between the alternator and the battery, and have another noise filter in the head unit’s power cable.
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RCA cables can be another reason for the whining noise, as they tend to pick up noises in their path. To fix this, make separate paths for RCA cables and power wires – ensuring they do not cross each other.
Another fix you can try is shielding these cables or replacing them if they’re damaged.
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Poor Amp grounding
In case you have an aftermarket amplifier, the amp grounding can be the reason behind the whining noise.
The amplifier requires a ground connection for protection against overloads (by providing a return path to excess current) and stable voltage levels.
But many DIY car enthusiasts make these connections poorly, which results in amp overheating, poor sound quality, and unwanted noise in the sound (due to ground loop).
To check whether your amp ground has any issues, you’ll need to check it with a multimeter.
Here’s how you can perform these tests:
- Turn off the amp and disconnect it from the power source.
- Set the multi-meter to resistance mode.
- Connect the negative multi-meter probe to the ground connection and the positive probe to a non-rusty, unpainted metal part of the vehicle that you know is a good grounding spot.
- The resistance reading should be close be 0 (0.1 Ohms, for example) for a good ground connection.
- If it’s higher, such as 1 Ohm, you’ve got a poor grounding and should fix it as soon as possible.
Some of the common things that can make a ground connection poor include
- Improper grounding point (painty/rusty surface)
- Loose/damaged ground connection
- Small gauge ground wire. It should be the same size as the power wire of the amplifier.
Therefore, make sure that your amp ground has none of these issues, and then test again to see if anything improves.
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Car Battery Ground Cable
In addition to the amp ground connection, every vehicle has a battery ground connection that connects the negative battery terminal to the vehicle chassis.
This cable to good enough for standard car audio setups. But you can get noise interference if a heavy-duty amplifier is installed.
To solve this, you need to upgrade this ground cable to a higher gauge.
The amp’s location also plays a critical role in the overall sound quality of your car’s audio system.
If you’ve placed it close to another electrical component of your vehicle, some noise interference can occur.
Therefore, if you’ve followed all of the steps mentioned above and nothing has improved, it’s worth tinkering with the amp location as well.
Aftermarket Head Unit
Sometimes, you get a noise in the sound as soon as you upgrade to an aftermarket head unit. That’s because the factory ground connection for the car radio was good enough only for the factory car radio.
As aftermarket head units are more powerful, they require a better ground connection. Otherwise, you’ll continue to get that noise.
Faulty Antenna/Antenna Cable
If you get noise in the sound only when you select the FM radio as the source and not with the CD, Bluetooth, or AUX, the problem is with either the antenna or its cable.
That’s why you should select any other music source to see if anything changes. If it does, then the antenna/cable is faulty and should be repaired/replaced.
So these were the most common issues that can result in whining or other noises coming from the car audio. As these noises can induce due to various reasons, we’ll have to check for all of the possibilities to identify the root cause.
If you’ve checked all of these components and found no issues, I recommend you consult a professional mechanic, as there can be some issues with the head unit, speakers, or amplifier, which require more technical expertise.
Frequently Asked Questions
Why Do My Car Speakers Make Static Noise When The Radio Is Off?
The most common reason for static noise in car speakers is faulty speaker wires or connections. Shake these wires a little and notice if there’s any change in the static noise. If there are, wires or connectors (or both) are bad.
How To Get Rid Of Engine Noise In The Car Stereo?
There are a number of steps you can take to fix the engine noise from the car stereo, such as shielding/re-routing the RCA and speakers cables, reinstalling the car amplifier, or changing the alternator.
What Causes Whining Noise In Car Stereos?
You can get whining noise in the car stereo for various reasons, such as poor ground connections, a faulty alternator, low-quality RCA cables, damaged speakers, etc.
How Do You Remove Hiss From Car Audio?
You should properly set the amplifier gain as it’s one of the common issues related to hiss in the car audio.