Rear speaker whine (engine noise), why...?

[sleepy stevey 10+ year member]

I give up... you people are getting so far off topic it is retarded.

It was not a ground. I moved my ground 3 times before any of this.. used a different wire, shortened it to less than a foot, etc. My amp is fine. I unhooked it while it was off and didn't just unhook a ground, where are you getting this?!

 

[jrz126 10+ year member]

Alright guys... I finally go around to checking it out. I removed all my rear panels, etc.. I cut the pull ties I had holding the wires together. I then pulled the rear speaker wire away from both sides... Started the car... and the whine was gone. I then had a friend of mine move the wire back and forth around the power wire while I revved the car, the noise came and went as he moved it. Anyways I talked with my uncle, he majored in electrical engineering and he explained that of course the speaker wire could receive EMFs from the power wire that is was running along side of it and to run it perpendicular to have the least chance of it taking any in. Well, the noise is gone... I am happy... and the "myth?" about speaker wire running along power wire is apparently true. The speaker can pick up engine noise (alt whine, etc) from a power wire running along side of it.

So you were moving the actual wire going to the speaker? or was it the RCA's going to the amp? I'm pretty sure you're talking about the speaker wire itself but I just want to make sure.

If thats the case, then it kinda sounds like you have some bad diodes in your alt.

The alternator generates an AC Voltage which is then converted to DC by the diodes. If the diodes are bad, then you'll have a very bad ripple in the voltage output which would generate the EMF to cause the noise.

I think its bad diodes or something because it would take a very large ripple to generate a large enough EMF to induce into the speaker wire.

I think you can check this by taking a multimeter and set it on the AC setting and connect it to a + and - . That should only indicate the amount of AC voltage on the line. Also, Autozone will run a test on your car for free and they will check the Alt. output. (volts and amps) and it'll check the diodes along with some other things.