I just installed an amp and a sub in my car...

Kenwood KAC-X812 - 919W @ 2ohms
Alpine SWX-1042D - DVC - 500W/coil @ 4ohms
4 gauge wiring

I used the jumpers to run the sub in parellel and I am running the amp at 2ohms.

When I get the sub at about 40% my lights start to dim if I turn it up a little bit more, I get a lot of distortion from the sub.

How do I fix? Capacitor? Alternator?

 

A 900 wrms amp will draw about 50-60 amps continuous. Average car needs 80 amps, with lights, a/c, ignitian, rear defrost, etc. + 20 more for charging.

If your wiring is up to it and your alt is 150 amp, you should be good to go.

I have 140 amp factory alt, 0 ga. wire and 3F cap. I don't play it loud while i'm using all the electronics in the car, or the voltage drops.

 

Search for "Big 3"

I just did an older Cavalier with about 850 watts, and the lead coming from the alternator (about a 12 guage fusible liknk) was so hot it burned my finger, after 10 minutes of playing/running.

 

Sounds like sum 1 has a ground problem..............

 

I just checked my setup and the idiots who installed my amp (Bestbuy) ran the power and the RCA cables on the same side of the car. When you want something done right, do it yourself.

 

Its been shown that running RCAs next to power wire does not effect noise...That is an old myth IMO... (an amp can't pick up fields caused by DC current flow!)

the noise we are worried about is caused by alternating magnetic fields....

If your noise went away when you moved your RCAs it was more then likley for some other reason...

 

And suppose we put the power interference issue out of the question, the problem was still fixed because the OP moved the RCA's. Fortunate coinidence. I've seen this in my own car. If the RCA's were laid a certain way, they picked up alternator whine.

 

Really? I am running all my wires under the drivers side molding and am getting alternator whine(temporarily, I haven't had time to install my 2awg amp kit that I am putting on the passengers side to my other amp). My ground it metal to metal, took the paint off. I am in the process of upgrading the big 3 wiring to 2awg, done the chassis to engine and the battery to chassis, alternator to battery is next on my list.
I'll let you know how it works out.

 

You couldn't be more wrong. I find it funny you call it a myth because it is a proven fact, prooved right over and over by pretty much every car audio installer for god knows how long. Excessive amounts of amperage travelling through a wire indeed, cause a magnetic field, which if near signal cables, will induct noise. This was much more so, back when class D amplifiers were big, because the class A/B subwoofer amps were drawing HUGE amounts of current to give you the same output as modern class D monoblocks. But thats just my opinion (as well as countless others)