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arron9999

Electrical noise/alternator whine radio

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morning 

 

So i have been having a problem for a while with my audio, 

 

I fitted a sub and changed my food /roof speakers while amping them up. When i do i have alternator whine coming through them, i checked my grounds and changed them but still the same problem. 

 

I have now removed the sub and amp, leaving the door speakers in place but only using the HU to power them. doing this i get no whine through the speakers.

 

 Im trying the trace the issue back to source so i can fix it then complete my install but have noticed something.

 

The fuel pump under the rear seat seems to be making a alternator whine ish noise as when i accelerate i hear it, I have tried to confirm this by lifting the rear bench and the noise did get louder. 

 

Also when using the radio the reception is perfect when the car is off, but once started i only receive the very strong channels eg radio 1 all the others that were being received are now a hiss, 

 

Appreciate any help 

 

Thanks

Arron 

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would like to add that i have tried to search for a answer and have read about the Diversity receiver however my key works from along way from the car so dont see that being the issue.

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28 minutes ago, arron9999 said:

Appreciate any help 

 

If you can be more specific about your vehicle, you will get a better response. What year, model and chassis?

Edited by jake13

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1 hour ago, arron9999 said:

Also when using the radio the reception is perfect when the car is off, but once started i only receive the very strong channels eg radio 1 all the others that were being received are now a hiss, 

I don't suffer this problem on my basic iDrive audio E61. Possibly points to other tailgate related wiring, Diversity module and third party divices (cheap USB etc.).
Check voltage from Alternator, not sure how but maybe verify the condition and functionality of the alternator regulator and brush gear?

 

Not alternator whine but for reference, I once wrote in this thread (E61 Touring - Optimal boot sub(s) location.):

Quote

Noticed some CPU like electronic interfearance being dragged in from somewhere, maybe the hi output feeds running too close to kit in the bottom of the boot or along side wiring looms without using twisted pair wiring. Luckily when the boot Amp is switched into sub frequency mode the interfearance is not a problem and is largely filtered out.

So I let the HU drive the rear/roof speakers (with stock High Pass, no sub bass).

Wish I could help more :(, hate these kind of issues when trying to improve on BMW's excuse for an audio system.

 

It took me a while to figure out what the basic iDrive was actually doing :wacko:, plus the help from this forum.

Was yours originally a basic audio setup configuration?

So how have you wired up your Amp, fed by the iDrive Head Unit from which channels?

 

 

Edited by DarkHorse

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I have the basic audio but with pro nav + 6 cd changer.

 

I do have a USB connection in the centre console but nothing is connected to it and im still getting the issue, 

 

The audio is terrible for such a expensive car off the line, 

 

i took the low frequency from the under seat sub and ran a extension to the boot where i used a hi low converter. 

same with the 2 door speaker and roof speaker. 

 

This has however been reverted back to Stock ATM bar door and roof speaker while trying to diagnose this issue. 

 

Thanks

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Sounds ok.

Someone else might have some other ideas for solving the whine interfearance.

Earthing, chokes, capacitor smoothing, cable re-routing... bloody annoying, good luck.

 

 

Or alternatively maybe consider running the sub only from the boot Amp and filter out most of the whine noise if possible.

If that fly's, then:

Run the roof/rear speakers stock HP from the HU.

Run the front door speakers from HU with an LP crossover to leave the remaining bass frequencies to better serve the under floor subs that are in parallel.

Add some cheap 4ohm tweeters with a HP crossover in the front door quarters (again in parallel on the front channels).

 

The crossovers should more efficiently and cleanly distribute the frequencies to the front speakers that are best suited for the job.

That's been good enough for my music tastes on a tight budget.

Not perfect but louder and clearer in all frequencies and plenty of spare bass (if the boot sub location and signal phase is closely matched with the under floor subs).

 

 

 

 

Edited by DarkHorse
details and updates

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