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.
What Causes Engine Noise?
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.
To be sure, unplug the antenna and check if the noise disappears. The noise will vanish if it’s antenna noise.
2. Radiated or Sideway Noise
If your antenna is not the culprit, try pulling out the receiver while playing a CD.
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.
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.
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.
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.
Finding the Noise Source
To fix the noise problem, you need to find the item causing the noise.
You can then proceed to fix the problem using a suitable method. Follow these steps to pinpoint the source of the noise.
1. Check the Antenna
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. Check the engine
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.
3. 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.
4. 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.
5. 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.
6. Check the Battery and Alternator
If the noise is a high-pitched whine which 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.
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.
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.