Alternator Whine driving me crazy
 

Hey I own a 2005 350z and I just installed 4 infinity kappa 62.9i and a Kicker L7 pushed by infinity 4 channel 475a and a infinity mono 611a amplifier. I also have a kicker kx3 active crossover. I used the best rca I could find which was the monster 4 channel. After installing the everything I realized that I am getting some alternator whine and its driving me crazy. I tried grounding the RCA, I changed the headunit grounding point 3 different times and the whine is still there. Also the power wire and the rca is running totally on the opposite side of the car. I have a cheap double din dvd/navigation bought by a knock off chinese brand called lightinthebox. When I had the dvd player hooked up to my stock speakers I never had the alternator whine but now that its hooked up to the aftermarket speaker the whine is there. I just had the amplifier and crossover professionally tuned and the guy said the whining noise is most likely due to the cheap headunit. What do you guys think and is there any way I can find out if the headunit is defiantly the problem. He recommended the Kenwood double din but before I invest on a headunit that costs almost a thousand dollars I want to find out if the headunit is defiantly the problem.

It sounds like you did everything right...although now you are at the mercy of a shop to find the problem. The Kenwood DD is a great HU, and if it fixes the problem, then not only will you be happy with the results but also the performance of the new HU.

Have you tried a ground loop isolator? It's a $20 solution and often works wonders. I tested my system with and without, and could not tell a difference in SQ or SPL with the GLI, but it saved my sanity after trying every solution on the internet.

^Yep. Sometimes it's the only way. Put it on the inputs to the highs amp and not the sub amp as they can kill bass response.

If you suspect it is the deck, pull the RCAs out of it. No noise = probably the deck. Still noise doesn't eliminate the deck but it says there may be more than one culprit. You can also try grounding the outer ring of the RCAs at the deck.

So what your telling us is that all this was installed by a pro or by you? I did not catch that . I heard that its tuned by a pro but never said if it was installed by one. Not that it makes to much of a difference ( I was a store owner / installer for lots of years ) this is a little known secret that the pro installers don't want you to know. They are not magicians nor are they always right, A slow well organized first time installer can do just about as good a job as anyone else.

The most important thing to remember when dealing with pros sound salesmen and installers is " THEY ARE A BUISINESS " first and foremost. I know first hand what they are all looking for. Now before I get bad mouthed and told I don't know what I am talking about or to shut up about bashing shops and installers. I am absolutely not bashing anyones company or methods of installing what so ever. What I am saying is think about your install and wire things slow and steady. Watch the corners for the metal. Watch the clips of all the interior panels one small slip or to hard of a pull on one end can cause metal to slice its way thru the non cunductive covering of wires RCA's included. If you have a small knick in the outter skin of a wire it can cause leakage and if power can get out then sounds that are unwanted can get in Like Alt Whine. The simpleast thing is I know you have probably heard it a million times do not run power wire with sound wire ( IE. RCA with Power or Ground. ) Next always have a rubber gromet around any wire comming thru fire wall or any other metal surface what so ever. Also never install an amp next to a motor or actuator. From these you can get some other Ideas what not to do . I hope this helps you .

As for getting a new H/U well do that when you want to and have to not to eliminate something as small as a whine. Go Borrow another H/U and see if that happens to it also. Make sure the H/U your borrowing has all the power need you are looking for and need. If it does not do it with the borrowed H/U then check the RCA terminals of the old H/U make sure the there is no wobble bad soder joint things like that. Then also scrutinize the after market wiring harnest make sure ther actual plastic plug in snot defective. Look for distorsion of the pastic, loose wire connections in the plastic.all these things do matter. Most of the time the wire harnests are constructed to a high tolerence but every now and again one will sneak thru Quality control and give the Car Audio Owner/ Installler / Salesman a huge gead ache . Like i said hope this helps and good luck let me know what and if any of my ideas helped.