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I used to be involved in car audio in the late 90's, and the people involved came up with many of these solutions via trial & error.

- Have a central grounding point - a steel car body has higher resistance than copper wire so using multiple ground locations will introduce voltage differences.

- Use a large gauge stranded wire for your ground.

- Use the same gauge wire for the ground as you did for the power wire.

- Keep wire runs short.

- Use twisted-pair wire for audio connections.

So for a multi-amp system, you'd run a large gauge wire from the battery positive to a distribution block, and from there to the head unit and amps. The ground from the head unit & amps would use the same diameter wire and be run to a central point. The ground strap from the car body to the battery negative post would perhaps be upgraded to the same diameter as the positive wire.




These are just the misconceptions the article talks about.


I suggest you look at my list and read the article again.

He is using ground loop isolators because of the length of his cable runs. In a car, that's not a problem as anything over 3 meters would be rare.

Single point grounding makes sense, because as I said, steel is a worse conductor than copper, so you'll end up with a voltage difference between your grounds (from each to the battery) if you use more than one.

So far as twisted pair, he strongly suggests using them to provide shielding against magnetic induced noise. They also provide good shielding against RFI - remember you've got 4-8 spark transmitters running at 900 to 5000 rpm interval in the engine.

And using the same size wire for both power and ground makes sense because different gauge wire has difference resistance.




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