How do you stop alternator noise in speakers?

Answer 1

You'd be surprised what it takes to resolve this stuff sometimes. It might not be as hard as you thought, but then again with those amps it might be impossible. Switching amps helps.

Sorry if I don't follow your thread completely to see what you've done but it's still pretty basic. Often you can break all the rules and everything comes out fine. Too, sometimes you follow all the rules and it still doesn't work. You have to change components - either get better or cheaper ones or at least different........

First of all you need to find out which component is noisy. Pull the RCA jacks out of the first amp and the second amp and see if you still get noise coming out the speakers. If you do, the problem is purely from power/ground and the amps.

a) Make sure that all the grounds come to a common location.

b) ISOLATE the amps bodies from metal contact. That means the you need to lift if off its mounts with spacers. The ground wire should be the only ground. NOT the amp body (sometimes reversing this solves the issue too). You can even mount on pieces of wood if you need to.

c) You can try a choke in the power lines but don't be surprised if this doesn't work. Honestly, this really shouldn't be necessary.

d) Put a capacitor on your alternator.

If you can - try to swap out ANY other amp with one of the ones you have. "Usually" a higher quality amp is much more likely to completely filter noise like this - you're getting what you pay for. But sometimes you can put in a dirt cheap amp that's fairly clean and it works better too.

Usually "more money" means better performance but like I said, you can swap a $100 RCA cable with one that is $10 and the $10 one can be noise free. I've had that happen. I've spent more money on cables (only) than most people spend on the head unit and found that $10 cables did just as well in the system.

And you can get RCA cables that have grounds on them at both ends to reduce induced noise - but I've had those be noiser than cheapo cables that I put in to solve the issue. It's worth a shot though.

As someone mentioned - turn down your gains way down (and use more powerful amps).

If the noise is coming out the RCA jacks then the head unit is noisy from it's power line or the induced noise is too strong relative to your signal (hope it's a least 4 volts).

a) Run the head unit of a separate battery you dragged into the vehicle for testing the power source. Noise - try to choke it at the power source or at the alternator with a capacitor.

b) If it's through the RCA cables - get better cables (or cheaper ones). Make sure that you're not running near power lines (you already did this).

It is okay to cross power, just don't run it along side for very long. I've broken this rule too and it was fine - each vehicle is can be unique.

If the issue is still the RCA cables you might have to get new amps that filter noise better (like alpine, for example) or get a head unit with higher voltage outs so you can turn down the gains on you amps (greater signal to noise ratio from higher voltage inputs).

As a word to the wise - if you do the above and you still get noise you'll probably have to swap amps or put up with the noise. You might find that paying the bucks to let the pros do it (they do this all the time) might be better and you'll be happier with the results in the long run. Probably changing one major component will shut down the issue. If you swap an alpine amp (not that they're the best by any means) for your front and rear speakers the problem would probably go away.

It only hurts your pocket once, but after a while you forget the pain and then you can enjoy your stereo.

(Oh, too, it might be overkill, but use spiral wound wires wherever you can). Speaker, RCA, even smaller power summed to the right sized for you watts. But don't believe that you can't get a really clean system with cheap RCA cables and 2 volt outputs because you can - in many vehicles, that is.....)