Speaker whine
10-03-2004, 08:08 PM
#1
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Speaker whine
Okay...I've regrounded several times...tried different ground wires..shortened them up. I have shielded rcas...power down opposite side of car...rcas seperated in the trunk..tried a ground loop isolator...turned gain down on amp...its still there. What do I do next?
10-04-2004, 05:34 PM
#2
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hey....check the RCA's....see if there r not touching the amp or the HU....that will cause the whine.....try new RCA's....is the whine incresing with the rpm's of the car or is it constant? if it is increasing with the rpm's then u have a alternator whine.......u said that u regrounded the amp couple times.....it may be a bad amp....what kind of amp is it and who makes it?
10-04-2004, 05:50 PM
#3
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I'll start super basic for now...come back and let me know if you've checked all this and still have the whine. If you do, I'll take you step by step to diagnose the problem.
Basics:
Are amps securely grounded on short run to chassis with paint scarped off...good solid, constant contact??
Try a few different places....seat belt hole?
RCA's run on opposite side of and not coming close to power wire?
Radio securely grounded?
Double check all this stuff, then let us know the results.
Basics:
Are amps securely grounded on short run to chassis with paint scarped off...good solid, constant contact??
Try a few different places....seat belt hole?
RCA's run on opposite side of and not coming close to power wire?
Radio securely grounded?
Double check all this stuff, then let us know the results.
10-04-2004, 06:50 PM
#5
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mines little whine, cant be heard with 6-7 volume. RCAs other side of car, rcas are coiled under the amp...but even when they were not it whined....regounded with short wires, several places, paint scrapped...radio is gorunded to a metal bar, common place, same place where my friend grounded in his max..amp is a planetaudio, did not do this in another car it was in...
10-04-2004, 08:29 PM
#6
what kind of head unit do u have? try re grounding the alternator as well has the battery. grind all ground contact spots down to pure bare metal. on my HU i have a DC/DC converter and if its not located away from the engine, i get serious whine. try using a smaller gauge wire like 4/2/ or even 0 but i dont think that will be needed.
things i need to know are what headunit, what size wires, where are grounds located... all these things will help. shouldnt be to hard to fix
things i need to know are what headunit, what size wires, where are grounds located... all these things will help. shouldnt be to hard to fix
10-04-2004, 09:18 PM
#8
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I have a Pioneer Premier DEH-8500MP. Replaced and cleaned the contacts on the negative battery cable that connects to the battery. Ill try adding another ground tomarrow. Im using my trunk latch as a ground now. I have tried removing plastic covers and going straight to frame. I have a 4g power/ground split into dual 8's for both of my amps. It still whined even when it was straight 4 guage into the amp. The amp is mounted using velcro to one side of the trunk on the trunk floor carpeting. (Yeah, not too pretty...but not point in false floor and making everything nice if it doesnt sound right yet.)
10-05-2004, 11:01 AM
#10
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Join Date: Sep 2004
Posts: 195
well both amps should be grounded in one place to avoid the ground loop....as it comes to whine i think that ur alternator is on it's way out...
ground both amps at the same location and see what happens.....we always ground amps at same spot to avoid ground look or noise later on
ground both amps at the same location and see what happens.....we always ground amps at same spot to avoid ground look or noise later on
10-05-2004, 01:27 PM
#11
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Im using Stinger Hyper Series RCA's. Amps are grounded to a 4 guage wire split off into 2 8's. I have a ground loop isolator on one set of RCA's, doesnt help. I had my alternator tested at Advance, I was told it was good.
10-05-2004, 02:57 PM
#12
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You should have everything grounded at the same place. Run a ground wire from your head unit back and ground at the same place as your amps. If this doesn't help try grounding half of your components within two inches of the others.
10-05-2004, 06:11 PM
#13
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erm...never heard of anything like that. My friend had the exact same setup in his max with headunit grounded upfront.. no problem. Shouldnt the ground loop isolator clear up the head unit being grounded up front even if that were the problem?
10-06-2004, 10:03 PM
#15
hope this helps
ok copyed this from somewhere on the web
The Ten Commandments
I. The best cure is prevention. I can't overemphasize this point. If you've ever spent an entire weekend tearing an installation apart in order to eliminate some noise, you know what I mean. Take the time to sketch the system out before you begin the install. This graphic representation of the installation will help you to avoid introducing ground loops and will serve as a road map for eliminating noise if it is present.
II. Don't introduce ground loops. Ground loops are created whenever an audio ground is established at more than one location. Theoretically, the only place the audio ground should be connected to the chassis ground is at the source unit. In my experience, I've found that in systems that have noise problems, a ground loop is the culprit nine times out of ten.
III. Never run signal wires alongside power cables. This is especially true in installations where high powered amplifiers are used. Large amplifiers are capable of drawing large currents. These currents vary with the musical demand of the program material as does the electromagnetic field surrounding the power cable. The more current that flows through the wire, the bigger this field becomes. If audio cables are located in close proximity to this fluctuating electromagnetic field, noise could be induced into the system.
IV. Always use 100% shielded audio cable. This will insure maximum protection against induced noises by power cables and other sources of electromagnetic interference. Good audio cables are not cheap. If you prefer to make your own cables, I would recommend using a wire with a foil shield surrounded by a drain wire.
V. Never use the ground wire in the vehicle's OEM radio harness. This wire usually makes a very poor ground due to it's length, small wire gauge, close proximity to other power wires, and unknown termination point. Instead, ground the source unit directly to the chassis or firewall.
VI. Make sure the amplifiers have a good audio ground reference. In order for the amps to function properly, the audio ground must be referenced to chassis ground at the source unit. If it is not, the amplifier could oscillate. To check for a good ground reference, take a volt-ohm meter (VOM) and measure the resistance between the chassis of the radio and the shield of the RCA line level outputs of the radio. This reading should indicate a direct short. If this is not the case, grounding the shield of the RCA line level outputs to the chassis of the radio will probably be necessary.
VII. Keep amplifier power ground wires as short as possible. The longer a wire, the more resistance it has. When a current flows through a resistance, a voltage drop is produced. Because of this, the ground reference at the amplifier's circuit board is no longer the same as that at the chassis of the vehicle. This ground potential differential can lead to noise and improper operation of the amp.
VIII. Don't connect all of your amplifier ground wires under one bolt. Contrary to belief, this is not required if the rest of the system is installed properly. If you do connect more than one power ground wire under a single bolt, you run the risk of amplifier ground modulation. This is caused by the current demands of, for example a woofer amp, modulating the power ground wire of a tweeter amp. This results in a squeaking noise that can be heard over the tweeters whenever bass notes hit.
IX. Make sure all levels are set correctly. Level setting is a critical part of the installation process. If done properly, maximum system signal to noise ratio can be obtained. Keep in mind that you want to drive the audio cables that feed the amps in the rear of the car as hard as possible. To do this, reduce the gain of the amplifiers to minimum. Turn up the volume on the source unit to 80% of maximum. Now adjust the input sensitivity of the amplifiers upward until the maximum intended loudness is obtained.
X. Noise filters can only reduce noise, not eliminate it. A noise filter is just that, a filter. And like any other filter (crossover network, etc.), it works by modification, not elimination. Some installers rely on filters heavily. In some instances a filter may prove necessary, but I believe that if the system is installed properly, a filter is usually not required.
About now most of you are probably making strange faces and saying "Now you tell me!" Well, all is not lost. If you have already installed your auto sound system and are unfortunate enough to have some noise, here are a few suggestions on where to look and what to do.
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 you've 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 it's power ground wire. Go to step 9.
Now it's 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 unit's 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 unit's B+ (yellow) wire directly to the positive terminal of the battery. If this doesn't do the trick, you will probably have to use a power line filter on the source unit's B+ (Yel) and Ignition (Red) wires.
The Ten Commandments
I. The best cure is prevention. I can't overemphasize this point. If you've ever spent an entire weekend tearing an installation apart in order to eliminate some noise, you know what I mean. Take the time to sketch the system out before you begin the install. This graphic representation of the installation will help you to avoid introducing ground loops and will serve as a road map for eliminating noise if it is present.
II. Don't introduce ground loops. Ground loops are created whenever an audio ground is established at more than one location. Theoretically, the only place the audio ground should be connected to the chassis ground is at the source unit. In my experience, I've found that in systems that have noise problems, a ground loop is the culprit nine times out of ten.
III. Never run signal wires alongside power cables. This is especially true in installations where high powered amplifiers are used. Large amplifiers are capable of drawing large currents. These currents vary with the musical demand of the program material as does the electromagnetic field surrounding the power cable. The more current that flows through the wire, the bigger this field becomes. If audio cables are located in close proximity to this fluctuating electromagnetic field, noise could be induced into the system.
IV. Always use 100% shielded audio cable. This will insure maximum protection against induced noises by power cables and other sources of electromagnetic interference. Good audio cables are not cheap. If you prefer to make your own cables, I would recommend using a wire with a foil shield surrounded by a drain wire.
V. Never use the ground wire in the vehicle's OEM radio harness. This wire usually makes a very poor ground due to it's length, small wire gauge, close proximity to other power wires, and unknown termination point. Instead, ground the source unit directly to the chassis or firewall.
VI. Make sure the amplifiers have a good audio ground reference. In order for the amps to function properly, the audio ground must be referenced to chassis ground at the source unit. If it is not, the amplifier could oscillate. To check for a good ground reference, take a volt-ohm meter (VOM) and measure the resistance between the chassis of the radio and the shield of the RCA line level outputs of the radio. This reading should indicate a direct short. If this is not the case, grounding the shield of the RCA line level outputs to the chassis of the radio will probably be necessary.
VII. Keep amplifier power ground wires as short as possible. The longer a wire, the more resistance it has. When a current flows through a resistance, a voltage drop is produced. Because of this, the ground reference at the amplifier's circuit board is no longer the same as that at the chassis of the vehicle. This ground potential differential can lead to noise and improper operation of the amp.
VIII. Don't connect all of your amplifier ground wires under one bolt. Contrary to belief, this is not required if the rest of the system is installed properly. If you do connect more than one power ground wire under a single bolt, you run the risk of amplifier ground modulation. This is caused by the current demands of, for example a woofer amp, modulating the power ground wire of a tweeter amp. This results in a squeaking noise that can be heard over the tweeters whenever bass notes hit.
IX. Make sure all levels are set correctly. Level setting is a critical part of the installation process. If done properly, maximum system signal to noise ratio can be obtained. Keep in mind that you want to drive the audio cables that feed the amps in the rear of the car as hard as possible. To do this, reduce the gain of the amplifiers to minimum. Turn up the volume on the source unit to 80% of maximum. Now adjust the input sensitivity of the amplifiers upward until the maximum intended loudness is obtained.
X. Noise filters can only reduce noise, not eliminate it. A noise filter is just that, a filter. And like any other filter (crossover network, etc.), it works by modification, not elimination. Some installers rely on filters heavily. In some instances a filter may prove necessary, but I believe that if the system is installed properly, a filter is usually not required.
About now most of you are probably making strange faces and saying "Now you tell me!" Well, all is not lost. If you have already installed your auto sound system and are unfortunate enough to have some noise, here are a few suggestions on where to look and what to do.
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 you've 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 it's power ground wire. Go to step 9.
Now it's 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 unit's 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 unit's B+ (yellow) wire directly to the positive terminal of the battery. If this doesn't do the trick, you will probably have to use a power line filter on the source unit's B+ (Yel) and Ignition (Red) wires.
10-06-2004, 10:21 PM
#16
i also forund this on the car audio mag website that backs up what i said before as well not to ground in the same place.
What causes alternator noise?
1. Induced noise through RCA's:
When a wire has current through it, a magnetic field circles around it (i.e electromagnets). Conversely, if there is a magnetic field perpendicular to a wire, current will be induced. If you have your RCA wires going from the radio or equalizer to the amp running in parallel to your power wires, an AC current will be induced and added to the sound signal. The sound signal travelling to the amp is a low voltage signal (in the mV range - thousands of a volt). The induced signal will be amplified along with the music.
Avoiding this problem is very simple: DON'T run power and RCA wires together. If there are points in which they do have to cross, try to place them perpendicular to each other. Run the power wire from the battery to the amp on one side of the car, and the RCA wires along the other side of the car. On most cars it is better to run RCA's on the passenger's side, and power wires on the driver's side. Note that noise may be also be induced by factory harnesses, car computers and other electronic equipment.
2. Ground loops:
Your car's electrical system (and your stereo) use the car metal chassis as a ground (there is always current flowing through your car's metal parts). If your battery and alternator are (typically) under the hood, and you are installing an amplifier all the way back in the trunk, then current flows through that power wire you ran from the battery to the amp, and back through the metal chassis to complete the circuit.
Theoretically the car's metal has no resistance, and it should not matter where you tie grounds for amplifiers, radio, battery and alternator. They all should "look" like the same point, right? Well, the metal in your car does have resistance, and there is a potential difference from the front of the car, where the battery is to the middle of the car, where the radio is, and to the back of the car, where most amplifiers are. The potential difference of the grounds makes the whole system act as an antenna, where they pick up noise. Measure voltages at battery, amplifiers and radio. There should be very little difference between the measured voltages. If there is a difference more than 1/2 volt, then you might have noise problems.
To fix this problem, make sure that the amplifiers have a good ground first. Use at least 10 Gauge wires for the grounds (and power). If you have 2 or more amplifiers, DO NOT go from the ground terminal of one amp to the other and then from there to ground, most likely you will have noise. Ground each amplifier independently. Same thing if you have added stiffening capacitors, go to a separate ground for the cap.
Troubleshooting
If you installed everything using the above guidelines and you still have noise, then try to figure out what is causing the noise (a very LONG and tedious process). First, double check grounds at amplifiers, crossovers, radio, etc. Make sure AM/FM antenna has a good ground. Try to figure out what is causing the noise. For example, if you have crossovers, equalizers, etc, bypass them by hooking RCA wires straight from the radio to the amplifier. If noise went away, you know problem is maybe RCA wires or grounds hooked up to crossovers/equalizers. If you have more that one amplifier and have noise only on one amplifier try switching RCA wires around. If noise stays the same, then problem is the amplifier, if it switches, noise is coming from previous components up the line. As said before, it is very hard to find out what is causing alternator noise.
Don't get one of those noise filter boxes unless you have completely figured out that the head unit or equalizer are causing the noise. 99.9% of the time you will be wasting your money in buying noise filters.
If you have tried everything in the world, and still have that annoying noise, contact your nearest car stereo shop. Some of them will be reluctant to fix something not installed by them, or maybe will charge you a lot for something you could not figure out that only took a couple of minutes for them to fix, so shop around first.
What causes alternator noise?
1. Induced noise through RCA's:
When a wire has current through it, a magnetic field circles around it (i.e electromagnets). Conversely, if there is a magnetic field perpendicular to a wire, current will be induced. If you have your RCA wires going from the radio or equalizer to the amp running in parallel to your power wires, an AC current will be induced and added to the sound signal. The sound signal travelling to the amp is a low voltage signal (in the mV range - thousands of a volt). The induced signal will be amplified along with the music.
Avoiding this problem is very simple: DON'T run power and RCA wires together. If there are points in which they do have to cross, try to place them perpendicular to each other. Run the power wire from the battery to the amp on one side of the car, and the RCA wires along the other side of the car. On most cars it is better to run RCA's on the passenger's side, and power wires on the driver's side. Note that noise may be also be induced by factory harnesses, car computers and other electronic equipment.
2. Ground loops:
Your car's electrical system (and your stereo) use the car metal chassis as a ground (there is always current flowing through your car's metal parts). If your battery and alternator are (typically) under the hood, and you are installing an amplifier all the way back in the trunk, then current flows through that power wire you ran from the battery to the amp, and back through the metal chassis to complete the circuit.
Theoretically the car's metal has no resistance, and it should not matter where you tie grounds for amplifiers, radio, battery and alternator. They all should "look" like the same point, right? Well, the metal in your car does have resistance, and there is a potential difference from the front of the car, where the battery is to the middle of the car, where the radio is, and to the back of the car, where most amplifiers are. The potential difference of the grounds makes the whole system act as an antenna, where they pick up noise. Measure voltages at battery, amplifiers and radio. There should be very little difference between the measured voltages. If there is a difference more than 1/2 volt, then you might have noise problems.
To fix this problem, make sure that the amplifiers have a good ground first. Use at least 10 Gauge wires for the grounds (and power). If you have 2 or more amplifiers, DO NOT go from the ground terminal of one amp to the other and then from there to ground, most likely you will have noise. Ground each amplifier independently. Same thing if you have added stiffening capacitors, go to a separate ground for the cap.
Troubleshooting
If you installed everything using the above guidelines and you still have noise, then try to figure out what is causing the noise (a very LONG and tedious process). First, double check grounds at amplifiers, crossovers, radio, etc. Make sure AM/FM antenna has a good ground. Try to figure out what is causing the noise. For example, if you have crossovers, equalizers, etc, bypass them by hooking RCA wires straight from the radio to the amplifier. If noise went away, you know problem is maybe RCA wires or grounds hooked up to crossovers/equalizers. If you have more that one amplifier and have noise only on one amplifier try switching RCA wires around. If noise stays the same, then problem is the amplifier, if it switches, noise is coming from previous components up the line. As said before, it is very hard to find out what is causing alternator noise.
Don't get one of those noise filter boxes unless you have completely figured out that the head unit or equalizer are causing the noise. 99.9% of the time you will be wasting your money in buying noise filters.
If you have tried everything in the world, and still have that annoying noise, contact your nearest car stereo shop. Some of them will be reluctant to fix something not installed by them, or maybe will charge you a lot for something you could not figure out that only took a couple of minutes for them to fix, so shop around first.
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