Annoying noise!

[Greg111 13]

Well as some of you may know, i have stripped all useless factory stereo wiring and amp out of the 3, am running four 4" split component Cerwin Vegas which are amped by a four way Clarion. To compensate for the lack of base coming out of the 4" components i have a 12" JVC Subwoofer powered by a JVC Amp.

Problem: I am told but want confirmation by you audio gurus that the annoying whine coming out of the speakers which goes up and down with the engine revs is due to earthing? Earth on the stereo? Earth on the amp? The noise drives me nuts and am just forced to turn the stereo off.

The same noise was there before the install change. What is it actually due to and how can i fix this?

Cheers.

[Guest Simon*]

I am not going to say anything at all

[Greg111 13]

I am not going to say anything at all

Nothing to do with that Simon.

[Forrest 35]

LOL Simon nice call

[Mark 178]

Yes it's an earthing problem. Have you run your speaker cables and power cables for the amp down separate sides of the cabin?

[Greg111 13]

Yes it's an earthing problem. Have you run your speaker cables and power cables for the amp down separate sides of the cabin?

All four speakers travel up to the L/R of boot where amp is mounted behind the carpet attached to the side of the car, amp earth is directly under amp attached to body.

[bravo 35]

Earth loop. Google speaker whine.

I found a really good troubleshooting guide on it which is now on my other PC, so sorry - can't link you to it just now.

In the end mine turned out to be a wire on the speaker (the one on the speaker cone) touching the car body when mounted (eventually isolated whine to only occur when speaker was mounted). Was an easy fix that took me weeks (and several curse words and hours on the internet and ripping the car apart) to find.

[Yankus 0]

I was gonna say are you sure the whine isn't coming from the next seat over?

But sounds like thats been eliminated.....cant get rid of my whine.

[Greg111 13]

Earth loop. Google speaker whine.

I found a really good troubleshooting guide on it which is now on my other PC, so sorry - can't link you to it just now.

In the end mine turned out to be a wire on the speaker (the one on the speaker cone) touching the car body when mounted (eventually isolated whine to only occur when speaker was mounted). Was an easy fix that took me weeks (and several curse words and hours on the internet and ripping the car apart) to find.

Ok, might try unmounting them all and see if this goes, so it's not actually due to the earth wiring itself?

[bravo 35]

Yep, could be - was just telling you my experience.

Could be: Poor amp earth, poor headunit earth, earthloop from amp casing onto car body (if mounted to metal part of car and amp is a cheaper brand or has internal earth short to its case), damaged or cheap RCA leads, blown fuseable link in headunit (usually caused by plugging things in with battery connected), poor earth on alternator, speaker wire touching car body etc etc.

Trouble shoot by isolating parts of the system. Disconnect battery. Unplug the RCA leads from the amp. Reconnect battery. Start car and turn on whatever you need to to get the amp to turn on (headunit, or switch, or however you have it wired). Turn the gain on the amp up gradually until you hear the noise (with motor running of course). If you get to max amp gain and no noise - problem is before the amp. If you hear it, problem is amp, speaker wiring or speakers.

Once you've done this post back with results.

[Greg111 13]

Alrighty, will try that, cheers Graham.

[sp8s 1]

Alternator whine?

[Greg111 13]

Alternator whine?

Had a chat with someone at Big Noise Car Audio and they suggested that too, i've changed every earth on the bloody sound system last night/this morning and no change so might rip the drive belt off and see if this changes anything?

The faint red circle under the amp shows where it was earthed, have no problem with this as I later put it straight to the battery earth with no change.

These are the components being used.

The amp isn't touching this earth block or the body as it's so light i've just Velcrod (sp) it in place.

As you can see i've pulled it all out and started from scratch, removed the earth from the stereo, removed the speakers so no accidental earthing from them, i removed the RCAs as you mentioned Graham and the noise then disappeared which is understandable as they deliver the information to the speakers, changed all other earths that work with the stereo, looks like it might be the alternator, what happens if it is? Simple as putting another earth strap on it?

Cheers for all the help guys, unfortunately trial and era is all you can do.

[rogan 7]

Pioneer head unit?

[jochen 4]

Pioneer head unit?

Alternator whine (which is what you are hearing) is normally caused by an earth loop, and sometimes caused by inductive pickup

To cure inductive pickup you need to separate the cables - in this case the inputs to the amp - away from any power cables in the car.

To cure an earth loop, you need to wire the earths in a star fashion, which is what BMW do to the audio system.

Additionally, BMW put a lot of care in their audio design to ensure the audio has potential-free inputs to the amp to avoid an earth loop.

You may find that you need to put a "hum buster" in the audio lines to the amp, to interrupt the shield of the RCA connectors, due to the distance between the head unit and the amp.

A hum buster is an audio transformer that galvanically isolates the audio input to the amp, thus breaking the earth path.

To test if this youle work, temporarily fit the head unit next to the amp, powered from same power and ground as the amp, and try it out. If no more whine, it is because you have stopped the earth loop by having all items at the same amp earth

When the head unit is in the front of the car, you have 3 x earth locations:

1. Headunit ground at its location

2. Headunit radio antenna - the coax shield is connected to ground at the antenna amp / antenna

3. RCA leads feeding the amplifier - they may be connected to ground at the amplifier

The loop occurs between the RCA leads and the vehicle chassis.

It can be very hard to stop this ground loop, which is generally due to insufficient isolation design in the amplifier and / or head unit.

Hence a hum buster may be the quickest and easiest solution

Other options:

[rogan 7]

There a problem specific to Pioneer in the RCA earth tracks inside the headunit. Causes exactly the symptoms described.

[E30BMA 0]

He's got one of those Ipod docking head units in it Rogan, pretty sure its a Fusion head unit.

[Greg111 13]

Alternator whine (which is what you are hearing) is normally caused by an earth loop, and sometimes caused by inductive pickup

To cure inductive pickup you need to separate the cables - in this case the inputs to the amp - away from any power cables in the car.

To cure an earth loop, you need to wire the earths in a star fashion, which is what BMW do to the audio system.

Additionally, BMW put a lot of care in their audio design to ensure the audio has potential-free inputs to the amp to avoid an earth loop.

You may find that you need to put a "hum buster" in the audio lines to the amp, to interrupt the shield of the RCA connectors, due to the distance between the head unit and the amp.

A hum buster is an audio transformer that galvanically isolates the audio input to the amp, thus breaking the earth path.

To test if this youle work, temporarily fit the head unit next to the amp, powered from same power and ground as the amp, and try it out. If no more whine, it is because you have stopped the earth loop by having all items at the same amp earth

When the head unit is in the front of the car, you have 3 x earth locations:

1. Headunit ground at its location

2. Headunit radio antenna - the coax shield is connected to ground at the antenna amp / antenna

3. RCA leads feeding the amplifier - they may be connected to ground at the amplifier

The loop occurs between the RCA leads and the vehicle chassis.

It can be very hard to stop this ground loop, which is generally due to insufficient isolation design in the amplifier and / or head unit.

Hence a hum buster may be the quickest and easiest solution

Other options:

Cheers for the advise, the head unit is Fusion, last night i removed the alternator belt and started the car, pretty much no noise after that, I fitted it back up and had another little play around with the all the leads and wires etc, removed the RCAs away from the speaker wires running to the amp, put them in a different location, spaced out the three RCAs that go into the headunit and just like that the noise is now gone, not even a little hum so pretty stoked with that! Only took around four hours

I'm getting quite good at removing E36 interior, good practice for the new job haha.

Cheers for all the help, i'm sure others will benefit from this advise too.

Just out of interest, what is this little unit? I'm guessing heater control module? Always wondered every time i see it, which has been a lot lately.

Edited April 1, 2010 by Greg.

[jochen 4]

IHKR = Integrierte Heziungs / Klima Regler

= integrated heating and climate control unit

[Greg111 13]

Oh yup, thought so, was just confused about the "Made in USA".