Contact us
Close contact box
Connect ID #
139 271 965 3
Connect ID #
139 271 965 3
All finished with your chat session?

We’ll email you a transcript of this conversation for your records.

All of our representatives are
currently chatting with other customers.

Please enter your name.  
Please enter a valid email address. Why is this required?
Please enter your US phone number.  

For Tech Support, call 1-888-292-2575

Thank you, !
Our conversation will be emailed to

Your Advisor,

More about me
Please enter a question  
Don't wait on hold. We'll call you back when it's your turn to talk with the next available .
Please enter your name  
Please enter your phone number  

Please enter a message  

Calls may be recorded for training and quality control purposes.

We are located in Virginia USA.

Amplifiers: How to Suppress Noise

Heads up!

Welcome to this article from the Crutchfield archives. Have fun reading it, but be aware that the information may be outdated and links may be broken.

Electrically speaking, your car is a pretty active place. Every piece of electronic equipment in your car, such as power windows, your windshield wipers, and the alternator, generates its own small electrical field. These fields can be conducted through the metal that makes up your car's body and chassis. They're not really a problem until they sneak into the audio components of your stereo system and become noise.

Check all connections
You can solve almost all noise problems, without the need for adding noise filters, by making sure that every component is installed properly, that high-quality equipment is used, and that the car's charging system is working properly.

Loose grounds cause noise
Before you begin poking around your sound system for the source of the noise, you should first check your vehicle's electrical system.

  • Check the battery fluid level and fill, if necessary
  • Make sure the battery leads are tight to their posts
  • Make sure the battery's negative-to-chassis ground cable is sturdy, intact, and tightly secured

Often, tightening or replacing a vehicle's ground cables will clear up the noise issue in the sound system.

How to diagnose and eliminate noise
Use the following diagram to diagnose and cure the most common noise problems associated with systems with outboard amplifiers. The idea is to isolate the specific cause of the noise so you can eliminate it. For a more detailed explanation on how to eliminate noise, see our Car Audio Noise Suppression Guide. If these tips don't solve the problem, it's helpful to be able to call on a Crutchfield Technical Advisor. If you purchased your gear from Crutchfield, or purchased tech support separately, you can contact them toll-free between 8 a.m. and midnight Eastern Time, seven days a week.

The Big Three
Finally, for those mechanically inclined, another good option is to perform the "Big Three" electrical wiring upgrade to your vehicle's charging system. This upgrade augments the battery's ground wire, the engine-to-chassis ground wire, and the alternator's positive lead wire with heavier (1/0- or 4-gauge) wire. This greatly improves your system's current flow and signal integrity, and reduces noise significantly.

Noise suppression diagramAmerican International AS100 Antenna noise filter Click to see graphic. American International S-25A Power line noise filters American International S-15A Power line noise filters Stereo Patch Cables PAC SNI-1 RCA Ground Loop Noise Isolator
  • Jay from New Port

    Posted on 10/27/2019

    I just want to add that - keep in mind the return path of the electron flow, the neutral! This is where a inline 3 lead, w/grnd. noise filter might work better. After all there cant be noise unless first the electrons make their way though the windings of the cooling fan and then infect the system on the return path neutral. (This is where I agree with Robert's recommendation of a dedicated circuit), EMI can be a culprit too with the presence of electro magnetism. Especially if the fan is close to speaker level wire leads via inductance. I'm troubleshooting this exact issue in my system. I didn't need a fan on the Alpine, but thought it would be cool to have;) I'm using the H.U. remote (blue wire) for the fan's power coupled with a little 104* thermo couple as a switching mech. It's working beautifully, just making whining noise when it kicks on. A EMI filter is on the way and will try to report back in a week or so.

  • Commenter image

    Robert Ferency-Viars from Crutchfield

    Posted on 2/26/2016

    Kenny, that cooling fan is definitely the source of your noise problem. The fan, being a big electromechanical device, is generating a ton of RF noise into the electrical system. The best thing to do is to get the fan entirely out of the stereo system's electrical circuit. Try the following two things: Change the grounding point for the fan. Give it its own grounding point directly to the car body and make sure it's solid. If that doesn't fix it, then yes, try a different turn-on point, preferably out of the stereo circuit entirely. If you need more help, you can get expert Crutchfield Tech Support - 90 days-worth for only $30. Check out our tech support page for details.

  • Kenny brown from Houston

    Posted on 2/26/2016

    I've never had any problems with background noise until I bought/installed a scorpion crossflow 8inch turbo cooling fan for my amp, I'm not sure if it's because I'm sharing my ground distribution block among 3 devices, or running it through my (hu turn on leads) is there another way to run it? As in running the 12v power to the ignition switch to the car/radio from the dash? Would that stop the interference?

  • Commenter image

    Alexander Hrabe from Crutchfield

    Posted on 2/8/2016

    James, if you're still having trouble, keep in mind that if you bought your gear from Crutchfield, you can call Tech Support for free help troubleshooting your system. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Check out our tech support page for details.

  • James from Canton

    Posted on 2/4/2016

    I have a 2012 Accord ex-l (factory amped version) installed a GM d9605 Pioneer 5 channel using speaker level inputs. I am getting a high pitched buzzing/hissing noice coming from speakers. I think it is only right side component also. Got some weird crackling coming out of the right front component. Adjusted gain and seems to be fine.

  • Commenter image

    Buck Pomerantz from Crutchfield

    Posted on 8/24/2015

    Martin, That sounds to me like a defective receiver. I suggest you go back to your installer or dealer and arrange for a return.

  • Martin Martinez from Studio City

    Posted on 8/23/2015

    I have a newly installed OEM GPS touchscreen car monitor that makes a loud high pitch crackling sound only when using the Navigation mode. It happens about 10 minutes apart, but its so loud I feel like my speakers will blow. What can cause this?

  • Commenter image

    Alexander Hrabe from Crutchfield

    Posted on 8/10/2015

    David, more than likely, the noise is there at all times, but road noise at higher speeds is drowning it out. It could be that a connection is not properly grounded. It's worth checking your wiring again. Take a look at this article on noise suppression for more ideas.

  • David Snodgrass from Ferdinand Idaho

    Posted on 8/9/2015

    I have utopia car speakers and focal amp. My problem is that I have background noise at low rpms in my car what do I need to buy to fix this. It was processionally installed and sounds good while I'm driving just would like to clean it up. This is the second time I have had this problem in my car. I had it in a Honda civic now it's in a Honda acord. Both had background noise.