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whining noise from speakers

2K views 8 replies 5 participants last post by  da_bull 
#1 ·
i just recently installed my system in a e38 1995 740i. 2 kicker solo-baric 12's with a kicker kx1200.1 amp. Pioneer 770mp HU. I hear engine diagnostics system running thru my speakers when the HU is on and the key is in 2nd position. I normally hear this comming from under the engine, but not through the sound system. When the engine is turned on and the headunit is running, i hear a very very loud noise comming through the speakers that raises in pitch as the car accelerates.

Any suggestions would be greatly appreciated!!
 
#2 ·
typically it has something to do with the way the headunit and/or amp is grounded.
 
#3 ·
The headunit used to work jsut fine with no problems when the amp was run on the stock amp harness power / ground wires. The speakers never had any whine or anything. I put in the new system and wired everything up with 8 and 4 gauge wire and now i have the whine. The setup is as follows.

Power 0 gauge to capacitor -- capacitor grounded to battery ground

((2)) 4 gauge outputs from the capacitor to a 150amp fuse holder and a 60 amp fuse holder.
Those 2 fuses run out to a kicker 1200.1 amp and a alpine MRV-F345 4 channel amp.

those 2 amps are grounded str8 back to the battery ground


This is the complete subwoofer setup in the trunk.

The original setup had no subs with the 4 channel amp running off the stock wiring harness.

Any idea why i migth get whining now, and or any suggestions to fix it.
 
#4 ·
check where your gains are set. a good starting point is to turn the gains all the way down, volume to 2/3 (35 of 50, or whatever yours is), and slowly turn the mid amp until the point of distorting the speakers, then back the gain off a bit.
 
#5 ·
Good news: I'm almost 100% sure it's your alternator
Bad news: I dont know how to fix it

I've known a few friends with this problem. If i recall correctly they fixed it by doing something with the grounding or the alternator. I'm sorry I'm not really of any help but it was years ago and I dont remember what they did to fix it. Hopefully I gave you a starting place to go off of.
 
#6 ·
grounding may be another route, but most of the time people turn their gains way past what they need to be. the gain isnt a volume, its actually a matching device for the radio and amp to talk to each other. turning up the gains to their max invites unwanted noise into the system, you can actually get the maximum power out of the amplifier without cranking the gains. thats the only reason i propsed this first.
 
#8 ·
if the sound is coming from the elements which are connected to the subs you'll probably need a noise filter! theres another post about this thing just a few posts below...check it...

Buy a noise filter and but it on the end of the RCA cable which goes to the AMP and then connect the noisefilter to the amp...should fix it right up!!
 
#9 ·
sometimes the filters work, but most of the time they dont. If they do, most will hinder the performance of the bass in your system, the way they are designed, the signal has to "jump" across a couple of windings (like an ignition coil). Which is fine for higher frequencies, but as the frequencies drop, its harder for them to "jump" the gap.
 
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