90 nissan sentra, I had a alpine 3342 EQ in this car before with no noise, I recently swapped out the EQ to a alpine ere-g180 EQ and wasn't happy with the amount of hiss it added, so today I swapped the EQ back to the 3342 and now I'm getting really bad alternator whine, the first time I had the 3342 installed I mounted the brain underneath the center console in front of the shifter, this time I mounted it in the trunk, I'm using a sony pre-amp only head unit. If I lower the volume on the sony all the way and have the volume on the 3342 set to 20 or above the whine gets really bad, the higher the volume on the 3342 the worse it gets. If I move the fader on the EQ to the opposite of where the RCA cables are connected there is no noise, does that indicate the noise is coming in thru the RCA cables? The cables I'm using are not really good ones. But I have tried a few different cables. Also I tapped the power,remote and ground wires into the wires that feed my kicker crossover, could that be why I'm getting noise now? when I used to have the brain mounted under the center console I had the power tapped into the wire feeding the headunit, and the ground went straight to metal. I'm ready to pull this EQ out and not use any right now, I currently have the RCA cable from my headunit running straight into my crossover and have no noise at all. Thanks for any help ypu can provide.
Replies (15)
swez on 04/18/2005 08:32:43
You have a ground loop issue going on here. Make sure all added signal processors and amps are grounded to the same location if possible. This has to be a bare metal connection to floor pan or similar structure.
Try that first and see if it helps,
Swez
ttocs on 04/18/2005 12:38:39
is that an amplified EQ? Sounds like you are getting noise into the system between the deck and eq. Did you run pwr and signal seperatly?
MrBrownstone on 04/18/2005 14:04:51
Consider gain controls as well. Is the EQ gain control turned up, down, in the middle. Give us your gain settings for the amplifier AND the EQ and I'll let you know if there's a likely issue with user error.
Of course, if you are using a 'cheap ass' EQ, odds are, it's the equipment, but I highly doubt it if you are using Alpine.
PS Please use paragraph in your posts. It's easier to read. Thanks
ahardb0dy on 04/18/2005 19:46:13
no, thie EQ is non amplified,
gain on the EQ is on the control unit re-read my post as to where I had it set, amp gain is set to 1/2 ( alpine 3555 bridged 2 ch 150 x 2),
ok this is what I did today, I disconnected the power and ground wires from where I had them connected and hooked them up to a power suppy I have ( astron 25 amp) there was less "whine", than I switched over to another set of RCA cables that I had run from the headunit to the crossover and the noise was much lower, I than reconnected the power and ground to where I had them connected yesterday, using the 2nd pair of RCA cables, it sounds ok now, I'm getting some noise when I turn the A/C on but once the volume is turned up slightly you can't hear it.
I'm going to look into some better RCA cables, possibly some street wire's zero noise cables.
What can I do to eliminate the "whine" from turning the A/C on?
Thanks to all who answered.
swez on 04/19/2005 07:11:15
Cheap RCA wires can be a problem as cars/trucks have noise potential issues in many parts of the car. Using better wires may indeed help. Try relocation of the RCA's from the HU and see if that helps.
Sounds like a ground loop issue with the system in general. HU back to other active devices. (EQ, Crossover and amps) Improper grounding of the HU and all devices in the audio chain, can cause this.
Also, what is the gain setting on your amp(s) If the gain settings are too sensitive, they amplify audio and noise riding on the RCA's or power lines. These lines should be on opposite sides of the vehicle if at all possible.
Swez
ahardb0dy on 04/19/2005 17:12:40
ok, last night after doing what I said, I thought the noise was less, but after driving it to work this morning I realized the noise is just as bad.
After work I bypassed the EQ ( RCA cable only) leaving the power ground and remote wires connected and it still has the "whine", so does this indicate the noise is coming thru the power lead? Or could it be coming thru the open RCA jacks?
oh, forgot to mention no noises at all with out the EQ in line so I don't think there is anything wrong with the grounds on the other components.
power is run down the drivers side, RCA's on the passenger side, using a distribution block in the trunk with 4 gauge going to a good ground ( removed paint under bolt) and the 2 amp grounds, crossover and my air compressor grounds all going to the dist. block.
Going to try running the power & ground for the EQ directly to the respective distribution blocks (power and ground) instead of tapping into the power and ground wires that go to the crossover the way it is now, will see what that does.
I only hear the whine thru my front speakers which are running off the Alpine 3555 amplifier ( 150 x 2 bridged), the gain for each channel is set at the 1/2 way point.
What is your opinion of the street wires zero noise series RCA cables, specifically the zero noise 3's?
Thanks for your help Swez, I knew I could count on you for a few replies!
swez on 04/19/2005 20:05:46
Street wires should be adequate. I was going to suggest that you power the EQ off the same power source and ground as amps and crossover. If the noise is still there, you may have a problem with that EQ unit. Normally, Alpine makes pretty solid gear... but once in a while, a fluke will get through QC testing and ship.
Hope this works out for ya,
Swez
ahardb0dy on 04/19/2005 23:18:33
this alpine EQ isn't new, I bought it off E-bay a while back but like I said in the original post I had it hooked up in the car previously and I don't recall any noise.
Is it possible for the noise to be entering thru the remote turn on lead? I left the remote wire tied into the wire going to the X-over. Tied EQ remote wire to the X-over wire with a scotch lock connector.
Do you recommend any other interconnects other than the Street wires?
The RCA cable from the head unit to the EQ is the same one that I used when I didn't have the EQ hooked up ( no noise) so that should be ok, the only additional RCA cable is the one between the EQ and the x-over ( which is a very generic, cheap cable, could this be the source of the noise? I don't have a better cable to substitute for this one right now.
What about the noise when I switch the fan on with the A/C? what would be causing that? Same problem I'm having now you think?
Any way the head unit (even though with no EQ there is no noise) could be the source of the noise when the EQ is in line? Head unit is starting to act up, it's a sony and it's about 15 years old.
Thanks for your help, I know noise issues are normally complicated to solve, I've seen books dedicated to noise problems.
swez on 04/20/2005 08:23:28
Most correct about solving noise issues. They are indeed the most challenging to resolve.
So far, everything is pointing to your EQ. Without EQ on the circuit, all is noise free. Add the EQ to audio chain and noise comes into play. Your wiring tap off the X-over REM is fine. Just make sure the power and ground wires are tapped from same power source as amps and X-over. Can use Scotch locks here too, off X-over.
Cheap cables from EQ to X-over may be an issue here, but leaning toward internal problems with EQ unit. The fact it is used... may be why the guy dumped it on e-bay... noisey.
The only other thing I can think of that night be of use here, an isolation transformer. They transfer voltage from one side of an inductive transformer to the other w/o the DC noise issues along with the signal. Something like this may work between EQ---> X-Over:
http://www.davidnavone.com/detail.asp?PRODUCT_ID=N-344
Swez
ttocs on 04/20/2005 10:58:02
take two-"Did you run pwr and signal seperatly? "
As for the AC noise, you probably ran your pwr wire across some point of the ac, probably the compressor.
ahardb0dy on 04/20/2005 17:11:30
please read entire thread as I answered your "take two" question allready, but to recap the power runs down the drivers side, the rca's run down the pass. side.
under the hood the A/C compressor is on the pass. front the battery and the power wire is on the drivers side, no they don't cross each other.
last try I'm going to take is to hook up the "brain" ( power, ground remote) inside the car near where it was previously and see what happens,like I said I don't recall any noise when the EQ "brain" was inside the car, I def. remember no noise when I turned on the A/C.
Will post results later, thanks to all once again.
ahardb0dy on 04/20/2005 19:58:10
I don't know why, but I removed the EQ "brain" from in the trunk and hooked it up on the floor on the passenger side of the front seat ( about 12" away from where it originally was) and there is very little "whine", I can turn the volume up on the EQ to about 30 ( 35 is max) before I start to hear the noise, at normal levels ( around 20-30) no noise, except when I turn the A/C on there is just a little.
I took the console apart and perm. mounted the "brain" where it was before, used the same ground that it was previously hooked to, hooked the power wire to the wire going to the head unit's constant power, and tapped into the remote lead on the RCA cable, tested it, same result as when I had it on the floor, can't explain why there is barely any noise when it's in the front of the car but in the trunk it sounds like the ole dentist drill. Also used same RCA cables as when it was installed in the trunk.
swez on 04/20/2005 20:51:55
Well, sounds like you have the noise to about the lowest point possible at the moment. One thing you may wish to try in addition, is to dial your amp gains up a wee bit.
Example: Say gains are set at 2 volts now, set them at 2.5-3.0 volts and see if that changes things for the better.
Good work so far though,
Swez
ahardb0dy on 04/20/2005 21:31:24
I wonder if I still replace all the RCA's with the zero noise cables if that would help further?
as to the gain, I'm not sure how many volts equal the setting of the gain control's on the amplifier, I didn't get the owners manual with the amp ( friend gave me the amp), and alpine's site only shows how to hook the amp up, no details.
thanks
swez on 04/20/2005 21:50:50
Hard to say what the HU preamp voltage is without a model number. Some are 2 volts, the better ones have a 4 volt output.
By adjusting the gains and listening to the noise factor, you may be able to dial things in just using your ears. Just set all EQ sliders to "flat" (0 boost, 0 cut) for test purposes. May need a buddy to adjust the gains on amp while you listen to results in the car. Abviously, the car needs to be running to get this right.
Better wires may help in this case. Since the HU is in the dash and the EQ is too, short wires are all ya need. Maybe 1 meter long is all. (39")
Consider Knukonceptz for these new wires. Very high quality and reasonable prices too.
http://www.knukonceptz.com/productDetail.cfm?prodID=KAR2-1M
Note these are twisted pairs. That design makes them reject noise better than flat, side by side pairs.
Swez
Replies (15)
swez on 04/18/2005 08:32:43
You have a ground loop issue going on here. Make sure all added signal processors and amps are grounded to the same location if possible. This has to be a bare metal connection to floor pan or similar structure.
Try that first and see if it helps,
Swez
ttocs on 04/18/2005 12:38:39
is that an amplified EQ? Sounds like you are getting noise into the system between the deck and eq. Did you run pwr and signal seperatly?
MrBrownstone on 04/18/2005 14:04:51
Consider gain controls as well. Is the EQ gain control turned up, down, in the middle. Give us your gain settings for the amplifier AND the EQ and I'll let you know if there's a likely issue with user error.
Of course, if you are using a 'cheap ass' EQ, odds are, it's the equipment, but I highly doubt it if you are using Alpine.
PS Please use paragraph in your posts. It's easier to read. Thanks
ahardb0dy on 04/18/2005 19:46:13
no, thie EQ is non amplified,
gain on the EQ is on the control unit re-read my post as to where I had it set, amp gain is set to 1/2 ( alpine 3555 bridged 2 ch 150 x 2),
ok this is what I did today, I disconnected the power and ground wires from where I had them connected and hooked them up to a power suppy I have ( astron 25 amp) there was less "whine", than I switched over to another set of RCA cables that I had run from the headunit to the crossover and the noise was much lower, I than reconnected the power and ground to where I had them connected yesterday, using the 2nd pair of RCA cables, it sounds ok now, I'm getting some noise when I turn the A/C on but once the volume is turned up slightly you can't hear it.
I'm going to look into some better RCA cables, possibly some street wire's zero noise cables.
What can I do to eliminate the "whine" from turning the A/C on?
Thanks to all who answered.
swez on 04/19/2005 07:11:15
Cheap RCA wires can be a problem as cars/trucks have noise potential issues in many parts of the car. Using better wires may indeed help. Try relocation of the RCA's from the HU and see if that helps.
Sounds like a ground loop issue with the system in general. HU back to other active devices. (EQ, Crossover and amps) Improper grounding of the HU and all devices in the audio chain, can cause this.
Also, what is the gain setting on your amp(s) If the gain settings are too sensitive, they amplify audio and noise riding on the RCA's or power lines. These lines should be on opposite sides of the vehicle if at all possible.
Swez
ahardb0dy on 04/19/2005 17:12:40
ok, last night after doing what I said, I thought the noise was less, but after driving it to work this morning I realized the noise is just as bad.
After work I bypassed the EQ ( RCA cable only) leaving the power ground and remote wires connected and it still has the "whine", so does this indicate the noise is coming thru the power lead? Or could it be coming thru the open RCA jacks?
oh, forgot to mention no noises at all with out the EQ in line so I don't think there is anything wrong with the grounds on the other components.
power is run down the drivers side, RCA's on the passenger side, using a distribution block in the trunk with 4 gauge going to a good ground ( removed paint under bolt) and the 2 amp grounds, crossover and my air compressor grounds all going to the dist. block.
Going to try running the power & ground for the EQ directly to the respective distribution blocks (power and ground) instead of tapping into the power and ground wires that go to the crossover the way it is now, will see what that does.
I only hear the whine thru my front speakers which are running off the Alpine 3555 amplifier ( 150 x 2 bridged), the gain for each channel is set at the 1/2 way point.
What is your opinion of the street wires zero noise series RCA cables, specifically the zero noise 3's?
Thanks for your help Swez, I knew I could count on you for a few replies!
swez on 04/19/2005 20:05:46
Street wires should be adequate. I was going to suggest that you power the EQ off the same power source and ground as amps and crossover. If the noise is still there, you may have a problem with that EQ unit. Normally, Alpine makes pretty solid gear... but once in a while, a fluke will get through QC testing and ship.
Hope this works out for ya,
Swez
ahardb0dy on 04/19/2005 23:18:33
this alpine EQ isn't new, I bought it off E-bay a while back but like I said in the original post I had it hooked up in the car previously and I don't recall any noise.
Is it possible for the noise to be entering thru the remote turn on lead? I left the remote wire tied into the wire going to the X-over. Tied EQ remote wire to the X-over wire with a scotch lock connector.
Do you recommend any other interconnects other than the Street wires?
The RCA cable from the head unit to the EQ is the same one that I used when I didn't have the EQ hooked up ( no noise) so that should be ok, the only additional RCA cable is the one between the EQ and the x-over ( which is a very generic, cheap cable, could this be the source of the noise? I don't have a better cable to substitute for this one right now.
What about the noise when I switch the fan on with the A/C? what would be causing that? Same problem I'm having now you think?
Any way the head unit (even though with no EQ there is no noise) could be the source of the noise when the EQ is in line? Head unit is starting to act up, it's a sony and it's about 15 years old.
Thanks for your help, I know noise issues are normally complicated to solve, I've seen books dedicated to noise problems.
swez on 04/20/2005 08:23:28
Most correct about solving noise issues. They are indeed the most challenging to resolve.
So far, everything is pointing to your EQ. Without EQ on the circuit, all is noise free. Add the EQ to audio chain and noise comes into play. Your wiring tap off the X-over REM is fine. Just make sure the power and ground wires are tapped from same power source as amps and X-over. Can use Scotch locks here too, off X-over.
Cheap cables from EQ to X-over may be an issue here, but leaning toward internal problems with EQ unit. The fact it is used... may be why the guy dumped it on e-bay... noisey.
The only other thing I can think of that night be of use here, an isolation transformer. They transfer voltage from one side of an inductive transformer to the other w/o the DC noise issues along with the signal. Something like this may work between EQ---> X-Over:
http://www.davidnavone.com/detail.asp?PRODUCT_ID=N-344
Swez
ttocs on 04/20/2005 10:58:02
take two-"Did you run pwr and signal seperatly? "
As for the AC noise, you probably ran your pwr wire across some point of the ac, probably the compressor.
ahardb0dy on 04/20/2005 17:11:30
please read entire thread as I answered your "take two" question allready, but to recap the power runs down the drivers side, the rca's run down the pass. side.
under the hood the A/C compressor is on the pass. front the battery and the power wire is on the drivers side, no they don't cross each other.
last try I'm going to take is to hook up the "brain" ( power, ground remote) inside the car near where it was previously and see what happens,like I said I don't recall any noise when the EQ "brain" was inside the car, I def. remember no noise when I turned on the A/C.
Will post results later, thanks to all once again.
ahardb0dy on 04/20/2005 19:58:10
I don't know why, but I removed the EQ "brain" from in the trunk and hooked it up on the floor on the passenger side of the front seat ( about 12" away from where it originally was) and there is very little "whine", I can turn the volume up on the EQ to about 30 ( 35 is max) before I start to hear the noise, at normal levels ( around 20-30) no noise, except when I turn the A/C on there is just a little.
I took the console apart and perm. mounted the "brain" where it was before, used the same ground that it was previously hooked to, hooked the power wire to the wire going to the head unit's constant power, and tapped into the remote lead on the RCA cable, tested it, same result as when I had it on the floor, can't explain why there is barely any noise when it's in the front of the car but in the trunk it sounds like the ole dentist drill. Also used same RCA cables as when it was installed in the trunk.
swez on 04/20/2005 20:51:55
Well, sounds like you have the noise to about the lowest point possible at the moment. One thing you may wish to try in addition, is to dial your amp gains up a wee bit.
Example: Say gains are set at 2 volts now, set them at 2.5-3.0 volts and see if that changes things for the better.
Good work so far though,
Swez
ahardb0dy on 04/20/2005 21:31:24
I wonder if I still replace all the RCA's with the zero noise cables if that would help further?
as to the gain, I'm not sure how many volts equal the setting of the gain control's on the amplifier, I didn't get the owners manual with the amp ( friend gave me the amp), and alpine's site only shows how to hook the amp up, no details.
thanks
swez on 04/20/2005 21:50:50
Hard to say what the HU preamp voltage is without a model number. Some are 2 volts, the better ones have a 4 volt output.
By adjusting the gains and listening to the noise factor, you may be able to dial things in just using your ears. Just set all EQ sliders to "flat" (0 boost, 0 cut) for test purposes. May need a buddy to adjust the gains on amp while you listen to results in the car. Abviously, the car needs to be running to get this right.
Better wires may help in this case. Since the HU is in the dash and the EQ is too, short wires are all ya need. Maybe 1 meter long is all. (39")
Consider Knukonceptz for these new wires. Very high quality and reasonable prices too.
http://www.knukonceptz.com/productDetail.cfm?prodID=KAR2-1M
Note these are twisted pairs. That design makes them reject noise better than flat, side by side pairs.
Swez
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