How to diagnose and suppress noise

An interactive flowchart to help you solve some common problems found in car audio systems

Electrically speaking, your car is a pretty active place. Every piece of electronic equipment in your car, such as power windows, 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 (especially wiring and cables) is used, and that the car's charging system is working properly.

Loose grounds cause noise
Besides the stereo system, noise can also come from the vehicle's electrical system. Often, tightening or replacing a vehicle's ground cables will clear up the noise issue in the sound 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

How to diagnose and eliminate noise
Use the following process 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 Crutchfield Tech Support. If you purchased your gear from Crutchfield, you can contact them toll-free seven days a week.

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Tyler Gilbert from Lodi

Posted on 11/27/2020

I have a static white noise type of sound coming out of my 6x8's. I have a Pioneer FH-S722BS deck and I think the problem is coming from the deck itself or the harness but I'm not sure. I've disconnected my amp and sub and the issue is still there. It sounds like the gain on the stereo is up to high. Should I try grounding the deck to a new spot instead of using the ground on the harness? I'm at a loss. My stereo sounds great but this static sound gets worse when I turn up the volume. This issue occurs when the car is running or not, it doesn't matter. My amp and sub are disconnected so I know it's not that, it's something to do with the deck itself. What should I do?

Buck Pomerantz from Crutchfield

on 12/6/2020

Tyler, Static usually occurs when there's a loose connection, often a ground wire somewhere. I don't know how noise can be coming out of speakers when the amp is disconnected, but maybe I'm not understanding the issue. It sounds like your best option is to take your car to a car audio dealership and see if their techs can help.
Mike Stafford from Miami

Posted on 7/29/2020

I have a thump at power off that I can't figure out how to eliminate. I use a Kicker Key180.4 and Sound Ordinance 2 channel to power my subs. Seems to be only in the subs, key off pause and thump. It's sound enough to startle people. Any ideas on what I need to do? I didn't mention I'm running a Uconnect factory system in a '17 Dodge Challenger

Buck Pomerantz from Crutchfield

on 8/3/2020

Mike, Because you bought that sub amp from Crutchfield, you can call Tech Support for free help with your system. Their toll-free number is on your invoice.
Douglas from Houston

Posted on 7/6/2020

Thank you for all of your articles. I have a Z3 Roadster, year 2000, 2.3 model (actually has 2.5 liter engine). I just replaced all the speakers and the amp. I have a constant "beeeeeeeeeep" only when the key is in the "ignition" position. I put the key in, and in the first click, which I understand it to be ACC, there is no beep, just crystal clear music. Then, when I turn the key again to the second click, the noise starts and remains after I start the car. When I turn off the engine the noise remains. It only goes away when I take-out the key. I have checked all the grounding. If it is a typical grounding or other issues, I would not have the crystal clear music with the first click of the key when I turn the key. Any idea? Thank you. Douglas

Buck Pomerantz from Crutchfield

on 7/7/2020

Douglas, When tracking down noises, it's best to start by inducing the noise and then finding its source by following this interaction flow chart. If you bought your gear from Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number is on your invoice. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Click on this link for details.
Dean Bowker from Sneads Ferry

Posted on 3/12/2020

I have 2007 Ford Five Hundred Limited. Noise came from passenger side rear speaker intermittently when car was turned off. Battery drained . Charged up battery and ran car and noise occurred intermittently while car was on with radio on or off. Noise eventually stopped. Turned off engine and waited and noise came back . Unplugged speaker in in trunk area. Sound didn't come back . Ran car next day no noise problems. Two days later car battery drained and slight noise now coming from driver side rear speaker. Disconnected that speaker in trunk and noise stops. Pulled out Radio (original Factory installed(model 7G1T18C815BA ) and inspected the 3 pug connections and antenna connection. Could not see any visible problems (loose wires , etc). Put radio back in an still have Popping sound or scratching sound intermittantly. Have unplugged both rear speakers. Have not had any problems with front or door speakers. Radio seems to be working fine otherwise . Could use some help before I take it to dealership.Thanks. Dean

Buck Pomerantz from Crutchfield

on 3/16/2020

Dean, It sounds like your 13-year old factory radio needs to be replaced. A dealership will be expensive. Why don't you give Crutchfield a call and talk to an Advisor about what will work best for you.
Jim from Loveland CO

Posted on 1/28/2020

Buck, 2020 GMC Acadia: Replaced factory radio with Alpine iLX-F259. Added all new Focal component speakers. Added a Alpine KTP445U 4-CH AMP. (Sub Woofer B-8PTB from Crutchfield). All Install from CarToys. Sound improved with much more depth. Note: the factory radio was not very good quality for my reason the go this route. Problem: I still notice noise especially in the vocal range even on all talk shows coming through. Same with songs via my USB flash stick . It just does not sound crisp and clean with music. I have spent a small fortune trying to get this tweaked. BTW...the Alpine iLX-F259 is a bit overrated for it's sound quality as it needed help with the added components. But the noise from the vocals and higher range is annoying. Just sounds "dirty". I don't have a CD with this when I read your diagnoses chart to trace out the problem. I have read about filters that go between the radio and the new Alpine amp? It does the same with the engine off or running. Going to take it to another CarToys and get a "fresh" set of ears to listen to it.

Buck Pomerantz from Crutchfield

on 1/30/2020

Jim, If your system doesn't have a CD drive, for that step you'd select Aux with no program playing.
Joshua Bottoms from Beaverton

Posted on 10/26/2019

2003 nissan Altima with Bose system. I installed a loc tying into rear door speaker wiring leading into stock amp. After installing my aftermarket amp and subs with the volume all the way down their is a hum coming out from the subs. It is a sterio amp. When I switch it to mono the hum stops. What could be causing this? Should I get a noise suppressor?

Buck Pomerantz from Crutchfield

on 10/29/2019

Joshua, Without knowing precisely what amp and subs you're referring to, we can't help you with advice. If you bought your gear from Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number is on your invoice. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Click on this link for details.
Frank from redwood city

Posted on 10/23/2019

I have a 2019 Honda Ridgeline RTL-T. Installed an Alpine sa60m amp to power a sub. I get a loud bass tone that builds up and disappears. This happens randomly but only when the gas pedal is pressed. As the sound builds up in volume, I can stop it if I press the gas further or if I get off the gas completely. Wierd thing is that the sound happens even when the audio is turned off. I get the same noise even when using a different amp. An Alpine mrv-m500.

Buck Pomerantz from Crutchfield

on 10/24/2019

Frank, Your Honda has an "Active Noise Cancellation" (ANC) system that emits low-frequency sounds which are supposed to cancel-out the rumbling road, wind, and engine noises. ANC systems do not play well with subwoofers. Some car stereo installers disable the ANC systems in the vehicles they work on.
Samuel Jordan from Little rock

Posted on 8/12/2019

I just recently installed a sub and amp in my car I've just found out that the car has a Built-in Bluetooth that picks up the engine and muffler is their any way to eliminate that sound coming throughout the sub are it just be a bad ground

Buck Pomerantz from Crutchfield

on 8/13/2019

Samuel, If you're talking about noise that tracks the engine RPMs, then it's usually a loose ground or power connection. If you're talking about noise generated by your vehicle's noise management system, whether noise reduction or augmentation, then you'll have to disable that system or forget about adding a sub.
Damian

Posted on 2/22/2019

I recently installed a Kenwood KDC-X303 and I'm having issues with it emitting a noise whenever the radio is on, even with the radio at 0 it still makes noise and gets louder when I turn the volume up. Ive checked my grounds and they all seem to be fine along with all my connections. I tried to follow the flow chart but nothing seems to work. What could be my problem here? (It was installed in a 1996 Jeep Cherokee)

Buck Pomerantz from Crutchfield

on 2/25/2019

Damian, Diagnosing and curing a noise issue is almost always a challenge. If you bought your receiver from Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number is on your invoice. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Click on this link for details.
Jack Gayle from Tea

Posted on 1/26/2019

I have a 2015 Honda Accord, I added a sub and amp, sometimes when i first start the car the subpulse, and does it every time I put it in reverse. I have a factory back up camera, and it goes away when when I put it in drive. It still tends to have some feedback issues even then. I left the factory head unit in, have tried different ground locations, used the high level inputs, currently using a audio control lc2i converter but doesn't change the feed back. Any suggestions? Will the crux piece help?

Buck Pomerantz from Crutchfield

on 1/26/2019

Jack, Your Honda has a feature called Active Noise Cancellation (ANC). The ANC system uses internally-mounted microphones to detect any "booming" sound in the cabin. It then emits a mirror "anti-noise" signal through the audio system's speakers, which effectively cancels those booming sounds and creates a quieter passenger compartment. Except when you want to add a subwoofer. An online search for "active noise cancellation" in your vehicle may bring up some interesting ideas on how to deal with it.