Speaker Engine Noise Causes and Fixes

Norvan Martin
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Aftermarket amplifiers, speakers, and other car audio equipment are always at risk of developing issues that affect audio clarity. Engine noise is a prevalent issue in these car audio systems.  It can exist in various forms and intensities, ranging from barely noticeable to unbearable.

The most common reason for engine noise through your speakers is improper grounding or the wrong ground location, alternator noise, or wining. Normally, this can be fixed by properly grounding, using an alternator noise filter, using an antenna filter, or using a capacitor.

If some engine noise is still seeping through your speakers and you need a more detailed fix, read on. 

Engine noise is caused by several factors, some of which do not originate from the car engine, as the name implies.

Sometimes, the noise coming through your speakers can be from multiple sources. Therefore, you shouldn’t rule out any possibilities when troubleshooting.

1. Antenna Noise 

The noise in your radio can be due to antenna noise, especially if it’s only coming from the radio.

Car Antenna Noise 

To be sure, unplug the antenna and check if the noise disappears. The noise will vanish if it’s antenna noise.

Fix: Check if the noise comes only from the radio or other items like a CD player. If it’s only coming from the radio, it’s probably antenna noise.

For further verification, unplug the antenna and check if the noise disappears.

2. Radiated or Sideway Noise

If your antenna is not the culprit, try pulling out the receiver while playing a CD.

Car Radiated or Sideway Noise

If the noise disappears, then it’s being radiated into your setup due to its proximity to a noise source (like a heater motor). Noise can also radiate from the exterior of the car including the exhaust and tires.

Installing a noise filter on the source’s power lead often eliminates the noise. 

3. Electrical Interference 

Your vehicle’s electrical system connects to your stereo and emits noise that can travel through the speakers. Electrical interference can come from many sources including small motors, inverters, transducers, and so on.

Car Electrical Interference

The noise is particularly prominent in aftermarket audio setups because they require power connections from a different source and might interfere with the existing connections if they are close enough.

4. Alternator Whine

A high-pitched whining that fluctuates in pitch with RPM can indicate alternator whine. This is caused by issues with your alternator, such as improper connections, grounding issues, and improper shielding.

Car alternator wine

Properly shielding your cables, making proper connections, and adequately grounding your car should eliminate the noise. If you only hear the whining noise when accelerating, check out this article.

Fix: The engine is only one possible noise source, and you should cross it off your list before moving to another item.

First, switch on your car stereo and adjust the volume to the maximum with the engine running.

Now, turn off the engine. If the noise stops, you know what the source of the noise is. Engine noise is usually high-pitched and increases in pitch with acceleration.

If the noise is a high-pitched whine that increases with acceleration, the problem is probably from your alternator.

Check if there are no poor connections or cables prone to interference. Ensure that the alternator and the battery are in good working condition.

5. Transmission Problems

An aging transmission can also leak noise into your speakers. A screeching or whining sound sometimes indicates transmission issues.

This can be resolved by simple lubrication, or you might need to repair your transmission.

6. Ignition Noise 

If you have an old car that hasn’t been tuned recently, you may have ignition noise.

This can occur if your ignition system is not well-grounded and broadcasts tick noises to other car parts like the air cleaner and audio system. A car tune-up should fix the problem.

7. Check Your RCA Cables

Replace each RCA cable with a temporary one (to eliminate the possibility of multiple faulty cables, do this with multiple cables simultaneously).

The noise will disappear if it’s caused by defective RCA cables.

8. Change your Stereo’s Location

Pull your car stereo from the dashboard and set it up for play away from the dash.

If the engine noise vanishes or is significantly reduced, it is likely caused by electrical interference due to poor shielding or proximity to a noise source.

9. Check the Ground Location

If the grounding wire is worn, displaced, or rusted, it can lead to noise because of excess electrons in a ‘floating ground.’

You should also ensure the grounding wire is connected properly to the battery and alternator.


How to Eliminate Engine Noise

You do not have to be a sound technician or engineer to stop the noise from your car stereo. Based on the source, you can use any of these methods to eliminate the noise:

1. Use an Antenna Filter

Installing an antenna filter between the antenna and the car’s receiver will eliminate or minimize radio static. This device breaks the ground path between them and prevents the noise from entering your audio system.

A good example of an antenna filter that will prevent antenna noise from entering your audio system is the Channel Master LTE Filter Improves TV Antenna.

2. Use a Noise Filter

A noise filter quickly filters out engine noise. These devices are easy to install, consisting of a coaxial plug, cable, and a filter unit attached to a socket.

The coaxial plug is inserted into the stereo socket of your system, and the RCA cables are connected to your speakers with an adapter cable.

A good example of a noise filter that will prevent noise from entering your audio system is the PAC SNI-1/3.5 3.5-mm Ground Loop Isolator.

3. Ground Your Electronics Properly

If the grounding cable is displaced, rusted, or cut, you should clean and reattach it to clean metal for proper grounding. You might need a replacement jumper if the old one is too damaged. 

If this doesn’t solve the grounding issue, you might have to change the ground location. Use a multimeter to test for a good ground location and set it for continuity. Touching the ends together gives a beep to show that it is set for continuity.

Firstly, clip one of the ends to a known good location (somewhere in the door jam, for example). You can then begin looking for a good location. The meter will beep if you’ve found one. Then you can hook up the stereo ground to the new location.

4. Use a Capacitor

A capacitor can also prevent undesirable interference from getting into the speakers. Choose a capacitor of the right size and correct polarity (negative) and fix it directly at the battery.

Conclusion

Now, you should better understand how engine noise gets into your speakers and how to eliminate it. If your audio quality is being polluted by engine noise, just run down the list until you find the problem. 

 

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Norvan Martin is the founder of BoomSpeaker.com. He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin