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Speakers Making Noise When Your Car Is Off? Here’s the Fix

Car dashboard

The first time you hear your car speakers start making random hissing or popping sounds when your car’s engine is off, you’ll likely question your hearing. The second time, you’ll know it isn’t you, but may still find it confusing or a little freaky. And when it starts happening all the time, you may just begin to think your car has a resident poltergeist.

Well, we’re here to tell you—your car almost certainly isn’t haunted.

Believe it or not, car speakers occasionally make noises when the engine isn’t running. Usually, these noises will sound like static (hissing sound) or a reoccurring tick or pop. It’s a rare, but not unheard-of occurrence that will quickly become frustrating. Thankfully, there is a way to fix it.

Like most issues related to your car’s audio system, if you’re not comfortable tinkering with the wiring or component parts of the system, we recommend that you seek the assistance of a professional car stereo installer or an auto electrician. However, if you don’t mind pulling machinery apart and fiddling around a bit to get to the bottom of things, and you like to save some money, read on.

Car start button
Image credit: Car start button by MikesPhotos, Pixabay

Diagnosing the Problem: What’s Causing Your Noise?

There may be one or more issues behind your problem, so getting to the bottom of the issue, may take a bit of trial and error. Here are the things to check:

1. Is Your Stereo Still Receiving Power While the Car Is Off?

In some vehicles, it is possible to listen to the stereo when the car is completely off, and this is one of the first things you should check. With your engine off and keys removed, try turning the radio on. If the radio can be switched on and plays, your stereo system is still receiving power from the battery when your car is off. Being able to play your stereo with the car off isn’t necessarily a bad thing, however. Random speaker noise can be more of a problem in vehicles in which the radio receives power while the car is off than in those in which it doesn’t.

If your car stereo does receive power when the engine is off, there may be a simple solution to your noisy speaker problem. Try switching off your radio before you turn off your car, as in most cases, this simple step will completely resolve the issue.

2. Do You Have a Problem With Electrical Interference?

Electrical interference is a common issue with audio equipment and could be the cause of your mysterious noises. Anything that emits a signal, or that can interfere with your stereo’s electrical signals, can cause your speakers to make odd noises. A problem could arise from something as simple as a cell phone left in a door pocket near a speaker or as a result of some other power source that runs close your speaker wiring.

Electrical interference is something is often an issue with stereo systems that have been fitted with an aftermarket amplifier. If you have had an amp installed, make sure the RCA cables that run from the amplifier to your head unit are not lying near the amplifier’s power wire (or any other power wire for that matter). This is a mistake commonly made by novice installers and thankfully, one easily fixed by moving either the RCA cables or the power wire.

 Interestingly, surveillance devices (electronic bugs) are often only discovered in vehicles when they emit signals that start interfering with the car’s speakers—perhaps something worth noting if you work for a government intelligence agency or you’re someone who might attract the attention of law enforcement.

3. Is Your Stereo Equipment Correctly Grounded?

Each component of your stereo needs to be grounded, including the head unit, amplifier, equalizers, and any other installed components. Grounding involves attaching a wire from the component to a bare metal bolt connected to the chassis. The ground wire should be firmly connected, attached to a bare unpainted surface, be as short as possible. The wire used also needs to be as least as thick as the wire that supplies power to that component. You should check all the connections and consider installing a thicker ground wire if needed

4. Is the Problem Only Present When You Listen to the Radio?

If the noises you can hear are only present with the radio is playing, as opposed to when you are listening to a CD or streaming music via Bluetooth, you may have a problem with your car’s antenna. To check this, remove the antenna wire from the stereo head unit. If the noise immediately goes away, you may need to install an antenna noise suppressor between the antenna and the head unit.

5. Is the Noise From More Than One Speaker?

The easiest way to check this is to place your ear near the speakers one at a time.  If you have just one speaker making noise, the issue is likely to limited to that speaker. It may be a loose speaker wire, or even that poor-quality wiring was used to install the speaker. Check this even if you still have the factory speakers installed, as a previous owner may have reinstalled the factory speakers prior to selling the car. We also recommend checking to make sure that there is nothing pressed up against your speakers, and of course, the speaker itself may be defective and need replacing.

Having checked all of these things and you still haven’t been able to identify and fix your noise problem, it may be time to call in a professional. Give your local car audio retailer or an auto electrician a call; they’ll be able to provide you with some options.

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