Noise on speaker when car is on

MaXiZ · 3rd April 2007, 03:33 PM

I've REALLY tried to search but didn't find nothing that can help me..
I've installed a quintus car amplifier (http://www.mchammer.it/Quintus1800.htm) and run all ok when the car is turned off.
But when i start the car i hear a "weeeee" from the speaker that go up with the rpm..
How can i remove it?

myhrrhleine · 3rd April 2007, 05:12 PM

Really can't troubleshoot across the net,
but my first guess would be ignition noise.
Try filtering the power better.

zigzagflux · 3rd April 2007, 05:48 PM

Ah yes, wonderful alternator whine. An extremely common problem.

First thing to check is the grounding of your head unit and amplifier. Many unibody cars have poor continuity of their metallic parts, so what you think is a good ground is likely not.

It is 99% sure not the amplifier's fault. Running a heavy cable back to the battery negative is also NOT a good solution, though it may help to prove out the problem. Technically, the alternator chassis is true ground anyway.

Your best bet may be to find a chassis bolt somewhere. What kind of car?

MaXiZ · 3rd April 2007, 06:38 PM

Quote:

Originally posted by zigzagflux
Ah yes, wonderful alternator whine. An extremely common problem.

First thing to check is the grounding of your head unit and amplifier. Many unibody cars have poor continuity of their metallic parts, so what you think is a good ground is likely not.

It is 99% sure not the amplifier's fault. Running a heavy cable back to the battery negative is also NOT a good solution, though it may help to prove out the problem. Technically, the alternator chassis is true ground anyway.

Your best bet may be to find a chassis bolt somewhere. What kind of car?

So connect the ground directly to the battery may not be the solution. right?
Anyway my car is an Alfa Romeo 156

zigzagflux · 3rd April 2007, 08:46 PM

Silly American, doesn't know much about Alfa Romeos.

Running a cable to your battery post is a simple test to verify you indeed are dealing with grounding issues. Whine would be expected to decrease. Long term it's not recommended, as USUALLY the resistance with a short lead to car chassis is less than that obtainable with a cable run all the way up to the front of the car.

Hmmmm. Of course, Alfa could be a midengine design, which means amp is in the front of the car, engine in the rear.

It's all the same.

Point is, verify you are using a solid, beefy ground for the amp. Short cable, preferably a bolted connection. Clean up the paint down to shiny metal.

You ain't the first one, my friend.

edjosh23 · 3rd April 2007, 09:55 PM

I agree that it is definately a grounding problem. From the car audio I have done I would suggest checking your amp ground. Making sure you sanded all the paint down where you are connecting to the body. Check and make sure that your voltage across your amp, using your ground, is the same as the battery. If there is a difference your problem is with your amp grounding. If it is about the same, check your head unit for grounding issues.

Josh

MaXiZ · 4th April 2007, 06:49 PM

I've connected the ground directly to the battery (about 2mt of wire) and the "weeeee" is nearly gone. I can hear it just a litle!

edjosh23 · 4th April 2007, 07:49 PM

A little DC offset from the amp is not bad. Since most of the noise is gone that means you need to better ground your amplifier. As zigzagflux said, beefy, short ground cable to well sanded metal.

Josh

MaXiZ · 4th April 2007, 07:57 PM

ANYWAY THANKS TO ALL FOR THE HINTS! REALLY THANX!!!!!
As always here i can find an answer to any question.

3rd April 2007, 03:33 PM	#1
MaXiZ diyAudio Member Join Date: Jun 2003 Location: Italy	Noise on speaker when car is on I've REALLY tried to search but didn't find nothing that can help me.. I've installed a quintus car amplifier (http://www.mchammer.it/Quintus1800.htm) and run all ok when the car is turned off. But when i start the car i hear a "weeeee" from the speaker that go up with the rpm.. How can i remove it?

3rd April 2007, 05:12 PM	#2
myhrrhleine diyAudio Member Join Date: Jan 2006 Location: Avalon Island	Really can't troubleshoot across the net, but my first guess would be ignition noise. Try filtering the power better. __________________ Just because you can't hear it doesn't mean no one can.

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3rd April 2007, 05:48 PM	#3
zigzagflux diyAudio Member Join Date: Oct 2006	Ah yes, wonderful alternator whine. An extremely common problem. First thing to check is the grounding of your head unit and amplifier. Many unibody cars have poor continuity of their metallic parts, so what you think is a good ground is likely not. It is 99% sure not the amplifier's fault. Running a heavy cable back to the battery negative is also NOT a good solution, though it may help to prove out the problem. Technically, the alternator chassis is true ground anyway. Your best bet may be to find a chassis bolt somewhere. What kind of car?

3rd April 2007, 08:46 PM	#5
zigzagflux diyAudio Member Join Date: Oct 2006	Silly American, doesn't know much about Alfa Romeos. Running a cable to your battery post is a simple test to verify you indeed are dealing with grounding issues. Whine would be expected to decrease. Long term it's not recommended, as USUALLY the resistance with a short lead to car chassis is less than that obtainable with a cable run all the way up to the front of the car. Hmmmm. Of course, Alfa could be a midengine design, which means amp is in the front of the car, engine in the rear. It's all the same. Point is, verify you are using a solid, beefy ground for the amp. Short cable, preferably a bolted connection. Clean up the paint down to shiny metal. You ain't the first one, my friend.

3rd April 2007, 09:55 PM	#6
edjosh23 diyAudio Member Join Date: Oct 2004 Location: Raleigh/Atlanta	I agree that it is definately a grounding problem. From the car audio I have done I would suggest checking your amp ground. Making sure you sanded all the paint down where you are connecting to the body. Check and make sure that your voltage across your amp, using your ground, is the same as the battery. If there is a difference your problem is with your amp grounding. If it is about the same, check your head unit for grounding issues. Josh

4th April 2007, 06:49 PM	#7
MaXiZ diyAudio Member Join Date: Jun 2003 Location: Italy	I've connected the ground directly to the battery (about 2mt of wire) and the "weeeee" is nearly gone. I can hear it just a litle!

4th April 2007, 07:49 PM	#8
edjosh23 diyAudio Member Join Date: Oct 2004 Location: Raleigh/Atlanta	A little DC offset from the amp is not bad. Since most of the noise is gone that means you need to better ground your amplifier. As zigzagflux said, beefy, short ground cable to well sanded metal. Josh

4th April 2007, 07:57 PM	#9
MaXiZ diyAudio Member Join Date: Jun 2003 Location: Italy	ANYWAY THANKS TO ALL FOR THE HINTS! REALLY THANX!!!!! As always here i can find an answer to any question.

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