Jamillionaire Posted March 28, 2014 Report Posted March 28, 2014 I am having a really hard time trying to solve this issue. I have a c230 and my system set up is stock non Bose system, amp powering 2 12's and sony gs600bt controlled by an ipad mini. I am getting a high pitch noise from the speakers mostly when my car turns on and I accelerate. I have ruled out that the sound is being caused by the amp for the subs. I fixed up the wiring that the previous owner had done and changed where the stereo is ground. Are there any other solutions rather than buying a noise filter?
never knows best Posted March 28, 2014 Report Posted March 28, 2014 Alternator Whine To me, alternator whine is the most annoying form of noise. For those of you who are lucky enough never to have been exposed to alternator whine, it sounds like a miniature siren that rises in pitch with the speed of the engine. Alternator whine is almost always caused by a ground loop. The following steps will aid you in locating and correcting a ground loop problem. Verify that all levels are set properly. (Click here for related article.) With the system turned off, unplug the RCA inputs to the amplifier. Start the vehicle and turn the system on. If the noise is gone go to step 8. If the noise is still present, it is coming from the amp or the speaker wiring. Continue. Turn the system off and disconnect the speaker harness. Start the engine and verify that no noise is present. In a few rare instances, I have actually heard speakers reproduce noise without being connected to an amplifier. This noise was being induced by power cables that were very close to the speaker wire. If you do have this type of noise, reroute the appropriate speaker lead and go to step 3. With the speaker harness still disconnected, check to make sure there are no shorts between the speaker leads and the chassis of the vehicle. A shorted negative speaker lead will create a ground loop by establishing a second audio ground reference point. If you do have a short, trace the wire out and repair it then go to step 3. With the RCA inputs and speaker harness still disconnected from the amplifier, use your VOM to measure from the shield of the RCA jacks on the amp to the chassis of the vehicle. This reading should not be a direct short (100 ohms or more is acceptable.) If this reading does indicate a direct short, you might have a defective amp and should contact the manufacturer for verification.(Note that there are a few "inexpensive" amps or boosters on the market that have their audio ground and electrical ground commoned internally. For units of this type, the information in this article will be of very little value.) If youve made it here, you know that the amplifier and speaker wiring are okay. Connect the accessories in front of the amp (crossovers, equalizers, etc.) one at a time and check for alternator whine. When each device is tested, there should be nothing plugged into the input of that device. In this way, we will work toward the source unit piece by piece. Be sure to turn the system power off before connecting or disconnecting any cables or accessories. Repeat step 9 until all accessories have been tested. If a particular accessory is causing noise, try disconnecting its power ground wire. Go to step 9. Now its time to connect the source unit. Do that now and test for noise. If noise is present, try unplugging the antenna. If the noise goes away, you will need to use an antenna isolator. This little gismo opens the shield wire of the coax to eliminate the ground loop caused by the ground at the antenna. If you still have noise, try connecting the source units ground wire in another location, preferably as close to the source unit as possible. Does the noise vary in amplitude when you adjust the volume control? If it does, the problem is probably power line related and not a ground loop. If this is the case, run the source units B+ (yellow) wire directly to the positive terminal of the battery. If this doesnt do the trick, you will probably have to use a power line filter on the source units B+ (Yel) and Ignition (Red) wires.
hazestorm23 Posted March 28, 2014 Report Posted March 28, 2014 Check the RCA's and make sure speaker wires or the RCA's are not close to the power wire
Jamillionaire Posted March 28, 2014 Author Report Posted March 28, 2014 I disconnected the rca's for the subs amp and the antenna and still got the noise. The stock system doesn't have an amp for the speakers, they are powered by the stereo so I disconnected the harness for the stereo and still get the noise, it didn't seem as bad though. So does this mean there is something wrong with the speaker wire?
BoomZoom808 Posted March 28, 2014 Report Posted March 28, 2014 I would double check the speaker wire and make sure its not grounding out to metal or pinched somewhere. 2010 Mazda 3s 2.5L Pioneer DEH-X9600BHS Knu OFC 1/0 SS Platinum AGM / XS Power XP750 Alpine PDX F-4 / Morel Maximo 5 + Coax 5 IA 10.1 / SSA XCON 12
Jamillionaire Posted March 29, 2014 Author Report Posted March 29, 2014 I checked all the speaker wires and they were all good. In a last try to figure out the issue I tried disconnecting the climate control since whenever I turn it on the noise goes away. When I disconnected it there was no more noise. Does anyone have an idea how the climate control is causing noise in the speakers and a possible solution?
kapone Posted March 29, 2014 Report Posted March 29, 2014 I checked all the speaker wires and they were all good. In a last try to figure out the issue I tried disconnecting the climate control since whenever I turn it on the noise goes away. When I disconnected it there was no more noise. Does anyone have an idea how the climate control is causing noise in the speakers and a possible solution? its possible the climate control and head unit are grounded at the same source ... find the ground wires for both (head unit, and climate control) and separate them.
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