My clarion dxz735 has the same problem, but it is completly unrelated to altenator/coil because it does it weather the car is running or not. The whining noise i hear through my speakers is the sound of the actual CD mechanism spinning or moving when i switch tracks etc...you cant hear it in normal play onnly when you are seeking tracks etc.. Funny thing is that it sounds fine when the amplifier for the front speakers is hooked up with the amplifier for the subwoofers (using the Line outputs located on the sub amp) and the main RCA cable is hooked to the rear outputs of the deck (without any kind of LPF in turned on in the unit itself) If i try to run a seperate pair of RCA cables hooked to the front RCA level outputs on the dash so i can run my front speaker amp seperatley (and regain control of my LPF and subwoofer contol in the head unit) i get this horrible noise, but only if they run on their own RCA's...if i hook up the front speaker amp to the subwoofer amp i dont get any noise at all. All grounds are good, the RCA's are sheilded and not damaged and i tried some other RCA's just to make sure. I cant seem to isolate the problem. I also re-grounded the deck to a better location. This is driving me mad! Especially considering its not altenator related. Any ideas?
I think I remember some people solving that particular problem(Nick's) by grounding the offending rca's(outside, not the signal) at the h/u. I've never tried this and am not entirely sure this is a great idea in all applications so a second opinion from Jonathan, Glass, etc. is probably warranted.
Hate to have you screw up your deck on my account.
there are alot of options here, ill try to list them, it could be alternator whine , if it varies with engine speed, it is most likely alternator whine. as the alternator converts engine power to electrical power it produces a tone based on frequnecy. The frequency varies with engine speed, in which the higher the rpm the higher the pitch of the noise. IF the noise IS present while your car is not running(you already said its not) then it CANT be alternator whine, so this is still a possibility unless its there while the truck is not running.
niext possible noise is "radiated" noise, this is often called EMR(electromagnetic radiation) in this it doenst travel through the power wires, but is trransmitter from the noise generating wire into whatever wire or circuit is withing the radiation field, its pretty difficult to correct because the path it follows is invisible. It is solvable and is not a reason to live with the noise. you can use a device called a "noise sniffer" or a EMR detector to find the hot sponts in the vehicle that are radiating the noise, for example, one of the most commen noise modes is when a head unit picks up the EMR that is radiated from the factory wiring in the dash. In this case you can use the head unit as a noise snifer since if you were to unmount the headunit and pull it gently away from the dah while it is playing you would notice the noise fading out. That meanst eh noise is being radiated from the surrounding wires and moving it away a few inches corects the problem, then you can jsut find the offending wire, usually the biggest gauge wire carrieing the current levels large enough to create a big noise field. Almost anything in the signal chain can pick up radiated noise. Power and preamp cables, processors, corssvers, speakers. Last is "ground loops" if you consider what is happeneing with a ground loop, it makes understanding easy, each component has a differnt lenght of of power wire and draws a differnt amount of power. That means that the coltage dop on each power wire is not exactly the same, So if your headunit is recieving 12.2 colts after line losses and the amplifier in the trunk getting 11.8 colts after its line loss the difference is .4 volts. This differnece can try to baliace itsself out by taking a shortcu through the preamp cables. the preamp cables should be carrying no more than the audio signals, so when you add alternator wine, it adds to the music, basiccaly just pissin you off mo and mo. lol To deal with a ground loop you need to find out where the loop occurs, If the coltage is tring to return to the engatice terminal of the battery by traveling though the body of the vehicle and the preamp cables there will be a difffernec. By installing a ground loop isolator, you can ofter add enough ciruit isolation to force the DC to travel only along the ground wire and the cahssis of the truck, while the musicle signal uses the preamp cables
but Nick's problem can't be alternator noise if it occurs while the engine isn't running.
Oh I've have yet to see one of those power supply ground loop isolators work well, and the line level ones can add distortion and reduce frequency response. They're just like LOC's in that they use a transformer to electrically decouple the signal by converting it to a magnetic field then back again. This isn't a perfect process and almost always alters the signal enough to be noticeable.
He'd be best off checking the grounds and if necessary ground everything in the same place. I've also had problems with alternator whine when lateral pressure was applied to a set of crossever outs. He probably ought to make sure none of his rca plugs are binding anywhere as well.
-Fishy
Nick_sq
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but ONLY through the front RCA outputs. Regardless of what cables i use or where i ground things. If i use the rear RCA cables set to full range and run both my amps off the rear RCA's (subs and speakers) There is no noise. Im baffled.
Also its strange the noise is of the actual CD mechanism...speeding up/slowing down switching tracks..You know the sound of a home cd player when you switch tracks and listen close? that squealing? thats what im hearing through my speakers!!
