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, or purchased tech support separately, you can contact them toll-free seven days a week.
Do you hear noise?
Or view the full chart here
Reader comments (19 responses)
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Kalpesh Manseta from Gujarat
Posted on 1/9/2019
I have got an Audi A4 Bose speakers and amp in my car with Pioneer Head Unit. I hear whining noise when I start the car. The amp has no RCA, please help me out. Thank in advance
Kalpesh, Whining noise that changes with the motor's RPMs is usually due to a loose or intermittent ground or power connection. It could be in the receiver's or the amp's wiring.on 1/10/2019
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Buck Pomerantz from Crutchfield
Posted on 11/27/2017
Jhampier, Without knowing precisely what factory amp and "aftermarket unit" you're referring to, we can't help you with advice. If you want a question answered about a system, you must identify the gear by brand names and model numbers so we can get the right information to you.
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Jhampier Montes from Orlando
Posted on 11/27/2017
What is advise on connecting shield for terminals on a factory amp to aftermarket unit. I hear static I'm the radio. Using rca to avoid using amp and head unit together causing other issues
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Buck Pomerantz from Crutchfield
Posted on 8/31/2017
Alex, It sounds like your amplifier's remote turn-on lead is not connected properly to a 12-volt source that turns off immediately when the car is turned off. Many cars keep certain electrical circuits live for a few seconds after the ignition is turned off. You shouldn't use any of those circuits for your turn-on signal. If you bought your amp 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.
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Alex from Venice
Posted on 8/26/2017
Have a '14 Lexus ES. Very Loud bass noise after car shuts off. I've had a powered sub in my car for about a year with no issues. Recently upgraded to a more powerful amp and sub, (wired from the start with proper size wiring to accommodate a more powerful setup). Have a LOC to create preamp outputs and a remote wire to the amp. Also recently added a Ground Loop isolator in an effort to remedy the noise. Still does it. Have to disconnect the RCA cables from amp before shutting the car off. Please help.
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Buck Pomerantz from Crutchfield
Posted on 8/11/2017
Jason, The first thing that comes to mind is to check and see if the USB cable has come loose from the receiver. Or maybe the cable is bad. 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.
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Jason Mangen from Bowie
Posted on 8/11/2017
When I plug my iPhone lightning cable into the USB cord connected to to the iPhone slot in my Kenwood dnx773s receiver I get a buzzing sound in the speakers. All other audio is fine. What could be causing this problem?
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sam
Posted on 7/28/2017
this looks awesome gonna run thru it as soon as i get home
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Josh
Posted on 3/26/2016
This is very helpful, thank you!
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
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
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
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
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
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
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
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
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
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