speakers and isolating interferance

[Smokey Eddy]

My alternator is coming through my speakers more and more lately
I wired a stand alone system completely separate to the factory radio & speakers.

2 x 5.25" in the front doors.175 watts each
2 x 6"x9" in the back shelf. 300 watts each
2 x 10" subs against the back seats in the trunk. 900 watts each

4 ga welding wire from the alt. To the 1000 watt 4 channel amp under the passenger seat that the 4 speakers share. From that wire, 8 ga shielded wire to the 1800 watt mono channel amp for the subs.

My guess is its because the welding wire is unshielded but why does only the rear speakers wine with the frequency of the alternator?

Will wrapping a magnet around the welding wire at the amp fix this?

[truckinwagen]

the sound is probably coming from the head unit, and you can get noise suppressors that go in the power lead to the head unit.

pretty cheap and easy to install

[Smokey Eddy]

Head unit?

[truckinwagen]

the cd player, radio, etc...

the part of the system that makes the music, and sends it to the amplifiers.

-Owen

[Smokey Eddy]

It gets power the same way the old deck did... its something that has gotten worse.
Perhaps the rca cables I used are crap.

[R.O.R-2.0]

alternator interference can be caused by lots of things. dirty grounds, head unit might pick it up, rca's might let it in..

die-electirc grease is your friend..

how big of a supplementary ground did you pull off the battery to the chassis? you need a 4 ga supplemental ground off the batt if you got a 1800 watt amp thats worth a damn, cause i know my 1600 watt amp needs a really good battery (2 would be better) and an alternator bigger than 65 amps.. my rabbit alt wont keep up, but the 90A unit in my GTI would just barely keep up..

[Smokey Eddy]

Hmm I have the 65 amp breed. Both amps turned all the way down. The amps ground to the sub frame. I should add a second body ground.

[VWCaddy]

What I find that works well is to run power AND ground wires from the battery (+ and - posts) to the audio equipment and supply all of that equipment with the power and ground from those wires.  I twist the power/ground cables together as they rub back into the cabin.  I don't use any sheet metal ground (only) and find that keeps the noise down.  Also run an active noise filter inside the cabin between those two wires before it hits the first piece of equipment.

With one ground for everything, there is minimal chance of a ground loop condition and twisting the wires keeps noise out (shielded would be better, but I find twisting the power/ground wires works about as well at much less cost:
- http://www.4crawler.com/4x4/CheapTricks/CBantenna.shtml#Power

[8v-of-fury]

Arte you running your power and speaker signal lines down the same side of the car??

I've heard it can cause problems...

[theman53]

VW caddy and others are right on. I was into car audio in the past and found on gassers with computers run your wiring AWAY from the computer. Also, if you still have problems after the above suggestions, then try to get better quality RCA cables. I went with the "name" Monster gold plated stuff and that pretty much took care of noise.
I forgot this too. My head unit produced 4v and 55ohm through the RCA's, it was an older competition unit, but the 4v feed pretty much will eat up ANY kind of interference of non shielded components. It will also give you a very clean sound Today's units should tell you what they have and if you are lower than 4v that maybe your issue.
A 1 Fared capasitor will help the small alt problem. Just make sure to charge it before installing

[8v-of-fury]

This is all very good information! I know how to wire in a sterio, but the fine tuning and getting the best of it is like japanese to me lol. I will be going with an upgraded sound system this spring-ish and this is gonna be very helpful.

[R.O.R-2.0]

Hmm I have the 65 amp breed. Both amps turned all the way down. The amps ground to the sub frame. I should add a second body ground.

if my amp turns on, and i dont have the supplement ground also hooked up, (it goes from the neg post to the shock tower is all, nothing special) it will operate for about 5-10 minutes, then go into protection mode because its gotta work to hard for power..

rule of thumb, if you pull a 4 ga power off the batt, make sure to pull that big of a supp ground too.. and for your monoblock, i would have either 2 runs of 8ga to it, or solid 4 ga all the way back to it.. 8ga is fine for the 4 ch..

how bad do your lights dim?

mine draws so much power it makes the GP light on the dash come on, and i thought it didnt even work!!

i would pop your alt off, clean the mounting points down to clean metal on the alt and bracket, and then die-electric the connections, and re-install. (the wire connections and on the case where it clamps to the brkt.

clean both batt terminals, and die electric them too

how cheap are your RCAs? pull your deck out and un hook them one pair at a time till the noise stops..

could be possible its the deck its self making the noise.. my Kenwood Excellon makes a little noise its self. not alternator noise tho, a little noise comes thru the sub even with the car off.

your deck might need a reference wire. you know what one is? its a wire that runs from the case of the amplifier, to the case of the deck. does not need to be grounded.. ive had to use reference wires before..

it took me days to get my GTI electrical system silent..

i have had nothing but 4v decks Lucas, and most make noise.. carb, diesel or EFI, ive had noise thru them all

and i think i agree about the monster rca's, or any good, shielded cable for that matter.

dont use black tape to install a stereo either.. just switching from black tape to butt connectors eliminated noise before..

[Jettagli16v]

x2 on high voltage rca outputs.
Makes all the difference with respect to sound quality.
I bought a Clarion CD/USB head unit with a 6v pre-out for $150-170
from SonicElectronix.com.
I would replace the head unit first,
it is your most likely source of whine.
-Brad

[R.O.R-2.0]

i would try and make your head unit silent first, unless its a cheapo crappy deck.

what kinda deck is it Ed?

[clbanman]

My money's on a ground loop problem at your amp. (although you can get a ground loop on your head unit as well.)   The fact that it's getting worse points to a ground that's deteriorating as well.  http://en.wikipedia.org/wiki/Ground_loop_(electricity)

Run RCA wires and the power/ground wire on opposite sides of the car if possible - that can help.   A heavy ground back to the battery helps, but if you ground to the chassis at the rear, especially on an older car, make sure you have no corrosion at the connection or your bolt/screw hasn't loosened off.