Grounding problems

[Apex 693]

I have recently hooked up a 4 channel amp to run my fronts and rears and am having problems with alternator noise threw the speakers. I have run the RCA leads as far from the Power cable as possible except where it re groups at the rear wheel arch and have earthed the Amp to the rear beam that runs under the tail light enclosures on the interior.

Is alternator noise common on BMW’s as I have done similar set ups in other cars without a hitch?

Is there a point in the back of the car in which you guys have had luck with grounding?

Thanks

Edited February 18, 2008 by Apex

[Yuen 16]

Probably just a bad ground point - try grounding it to the factory ground points. In the E36 these are located behind the rear seat backs which you just pull out, they are located just beside the doors. There is a rubber plug for wires to run through into the boot so run your amp ground through there. Not sure how similar the E30 is to the E36 though.

Edit: Are your RCAs and the car's power cable on opposite sides of the car?

Edited February 18, 2008 by Yuen

[Apex 693]

I have three sets of RCA's and a power cable that splits before rear seats at which point the power and RCA leads meat to go through to the rear panels.

I should have tested the sound with the car running before spending a day putting the entire interior back to gather.

Left AMP

Right AMP

I had to run these cables together at this point as it is a wagon and there is nowhere else to run the cables.

[bravo 34]

My amp is grounded to the body through a factory ground in the boot which your touring won't have in the same place unfortunately. I had a loooooong process elimnating alternator noise in my car. I checked all grounds about 5 times. I re-reouted wires twice and replaced the RCA's. I replaced the alternator and engine ground straps and cleaned the alternator mount points. I installed a suppressor on the alternator. I checked all my battery cables, and tried insulating the amp case in case there was an earth loop (even though I have a quality amp and it shouldn't be a problem).

All to no avail. It was only affecting amped speakers so I knew it wasn't the headunit, but just in case I tried a different headunit (in case the fusable link on the RCA's had gone). No fix.

Then I noticed it was much louder on the RH front tweeter, so I temporarily swapped the x-overs - no go. Finally decided to swap out the speakers. Problem went away - swapped them back and it came back. Turns out, my right front speaker had a bent connector and it was creating an earth loop against the speaker basket. A 2sec bend of the tab and reinstall and problem gone.

So I know your pain - these things can be impossible to find.

Here's some other help. Elimiinating engine noise

[Apex 693]

Well shoot me dead, after 20 hours of total install and re install time it turns out It was the bloody head deck. I thought it was strange that I have done a similar install before and had no noise what so ever. I just shot down to the second hand shop and purchased old head deck and it sounds heaps better. Safe to say im well pissed off with Pioneer’s product.

Thanks for all your suggestions and help guys.

[Yuen 16]

Doh! Glad to hear you got it sorted one way or the other.

[Five Star 0]

You didn't happen to let the RCA's touch did you? Or was it just a pioneer deck..

[QuickSilver 0]

unplugging rca's while the head deck is on I hear can blow the internal fuse which will cause engine noise.

[Apex 693]

Power was the last thing to be connected. Just one of those flukes I suppose. On the upside my system is installed extra bloody well now!

The system is really sounding good after a couple of months, am waiting on a new 10†sub to replace my 12.

[QuickSilver 0]

I think I heard your setup from a distance at the meet, it sounds really good, why 10"? Is the 12 too loud? I got a farely low power 12" and I reckon mines got just the right balance all round,

[Apex 693]

Being a rock fan im after more response and less drone, I have grown out of the show off aspect of my current 12â€.

Also, I can shallow mount the rather compact 10†Im getting so I will have more load space..It’s a company wagon after all

[Five Star 0]

There's 8 inch subs that'll outperform most 12's

What sub are you thinking of getting?

[Mike 1]

Being a rock fan im after more response and less drone, I have grown out of the show off aspect of my current 12â€.

Also, I can shallow mount the rather compact 10†Im getting so I will have more load space..It’s a company wagon after all

same reason i switched from 2 12's to a quality 10". The 10" actually has more grunt (power handling) than the 2 12"s combined anyway.

[Apex 693]

Its a Kicker compvt 10" shallow mount.