Stero Noise

[jekyll]

just installed new sytem in my 2001 325i . alpine 7998 focal utopias 3ways in front doors ,focal2ways kp2 in rear deck .mb quart 4250Q 4 channel amp running the mids and hi for bass using a rockford 1001bd amp to push 2 10inch hx2 rockford subs .wired with stinger expert 10g speakerwire and inxos rca cables.and 2 rockford caps. alsoput a helix noise filter on the alternator.replaced alternator with bmw replacement and replaced the coil packs.theres a humming noise and you can here the fuel pump pumping through mids and hi,s .check all the grouds .tryed running cables douwn center of car.running 2g &0g power&GROUND cables .all new eqipment except head unit which was sent out to alpine to be checked dont know what else to check

[da_bull]

Welcome to the forums.

Nice equipment choices. One thing comes to mind, turn the gains down. Your amplifier can produce the same power regardless of the gain. You just need to turn the headunit up more. A good starting point is put the headunit to about 2/3 volume, and turn the gains up just to the point of distortion, then back them off a notch or 2.

In the past, I have just moved a ground over 6 inches, and it got rid of all of the noise. A reference ground (16ga. or so) running from the case of the headunit to the point where your amps are grounded sometimes helps.

There are numerous other things to try as well. Your power wire placement isnt quite as important as your RCA placement. They are a low level signal and really susceptible to noises from your car. They need to be away form your power wires also. Good luck, hope this helps.

[Rookie]

I feel for you man, I have got a fairly annoying alternator whine in my system as well and everything but the sub system is completely stock. I think it is fucked and wrong how easy it is to get a whine. The biggest thing people keep telling me is to completely seperate power and signal wires. From the sound of it you have already tried this step. If you run a search on the forum for alternator whine I got some good responses from the guys on here as to how to fix it. Of course I still have a whine but I have been feeling hella lazy lately, and would rather spend time on the beach with my girlfriend than tearing apart my car at the moment.

[ian1974]

Hi, i had the same problem when i installed my system, I kept the standard Sat Nav in My 325 E46 and upgraded the speakers and installed an Alpine amplifier, worked great but with serious alternator noise, finally sorted the problem by changing the hi to low convertors that i was using to ones that are compatable with floating ground and common ground systems(Stay away from cheap Halfords convertors), so i changed them with ones made by stinger a Us brand and hey presto no more interferance, these give you gain controls on each channel so you can match everything to the stock gear they are aprox £39.99 each. I had also tried several noise supresors advised by several In car audio stores that did not work, be carefull you can waste a lot of money on things you dont need, on the word of so called professionals. I dont know if any thing here helps you but i know how frustrating interferance can be and to cure. There is a company called Soundlinx that make a lot of gear to enable instalation of audio to oem systems, they could help if your using Original equipment anywhere in your sytem.
I hope this helps.