FreeSpirit

I have an Alpine deck and Im having trouble finding a good spot to ground it to. I keep hearing a constant hum or vibrating noise. It gets overpowered at loud volumes, but at medium volume, its very annoying. I have tried a few spots and I have been getting the noise to reduce more and more, but I still cant find a good spot.

Is the factory ground on the black metal underneath the steering wheel? Because thats where my factory stereo ground wire was leading to. But it was definitely tampered with because there was another wire going to that same ground. So I made two separate grounds for the two wires. Less noise, but still there. And yes I am scraping/sanding to bare metal, on all points of contact, and using brand new star washers.

I have already narrowed it down to the headunit, its not the cables or amp.

So for those who didnt use the factory ground, where did you ground your head unit? I am hoping theres a good place to just hook the o ring to, because drilling holes didnt work out too good. Not sure if its my tools, skills, or both.

soul.justice

A ground is a ground. If it's to a solid point of bare metal on the body and connected securely with correctly sized wire, noise is getting introduced somewhere else in the system. Check your spark plug wires, make sure they are tight and free of cuts and nicks. Make sure all wires going to your speakers are secure. Check and clean your battery terminals. Don't use crappy RCA cables. Check your amp grounds. Swap in another head unit temporarily and see if the problem goes away. Double check all these things and if you're still having problems, look into getting a ground loop isolator.

You can also see if your head unit has a function to turn off the internal amp if you are running an outboard amp to your speakers. I had noise when I first installed my system but when I turned off the internal amp on my deck, I was greeted with blissful silence and clear music.

FreeSpirit

I made another thread about it, I have pretty much narrowed it down to my head unit. Amp works, RCAs work, and the head unit even outputs fine if I hook it to a mixer thats connected to my house AC power.

The yellow and red wires are 16 gauge, so Im using 16 gauge for the ground. I was using 18 gauge with a pioneer deck, with the factory ground, and had no problems. This Alpine deck is brand new.

Spark wires are good. I just redid the speaker wires and theyre good. Used 16 gauge wire. Cleaned battery terminals and also the battery to chassis ground. Added a star washer there too. That actually made my car run a lot better. Accelerates smoother now.

Amp and RCAs are fine, because I can leave them in place, hook up a coupler and dual rca to single 3.5mm headphone jack, plug that into my ipod, and it plays music just fine, with no noise. And yeah, I turned off the head units internal amp, didnt make a difference.

Is it true ground loop isolators affect sound quality? Im pretty sure that would fix my problem

soul.justice

Introducing any component in-line between your deck and your amp will by nature reduce your signal but I doubt you'll notice it. Are your RCA cables and power cables running side by side? If so, move your RCA cables as far away from your power wire as possible. I ran mine on separate sides of the car. What sources are you using for your music?

Let's troubleshoot everything we can before you run out and buy something you may not need.

FreeSpirit

No my rcas and power cables do not cross.. Sources? Ive tried radio and usb.. It happens as soon as the head unit turns on though, before it even plays any source

FreeSpirit

Tried grounding the RCA plugs, just for good measure, even though I have an Alpine. No difference. I cleaned battery to chassis, amp grounds, and head unit ground, yet again. I also put brand new star washers on every ground. No difference in sound.

FreeSpirit

Well I drilled a hole in the firewall, scraped the paint off the metal around it, and grounded my head unit there. It sounded great, no noise at all with the engine on. However, after I tucked my RCA wires away behind the panels, there is some noise again. Much quieter though, I can live with it. And I will probably be able to eliminate it by running the RCAs under the center console straight back to the amp.

mmadden55

You might want to get a filter usually less than ten bucks for your power lead and check to make sure you have resistor plugs and good wires.

ringo234

The ground isn't the problem the 12V line will have noise from the rest the car (alt, spark plugs etc. Try an EMI filter on the 12v going to the radio, or at least a bypass capacitor across the 12V to ground. That what I'm going to do.

FreeSpirit

Isnt a noise filter just a band aid? And doesnt it hurt the sound quality? I made sure all the grounds are good. They all have star washers between the ring terminal and bare chassis metal. I did the head unit, battery to chassis, and both amps. All brand new wire, washers, bolts, terminals. Im stumped. Still works great with the engine off

roadrunner90

Just from past experience, even if the RCAs and POS don't cross but are still close, they can transfer noise, that's why it's always good to run what transfers electricity as far away as possible from RCAs.

FreeSpirit

Right, sorry, thats what I meant to say. I know crossing them 90 degrees is the best way to cross them if you are forced to, and I didnt even have to cross any.

The only thing is the rear right speaker wire, it does cross the power line where they enter the trunk. They are in seperate looms but still pretty close. I disconnected this speaker from the amp, just to be sure, and the noise was still there. All the speaker wires were redone, except the fronts, just from the GM harness in the top of the dash to the stock wiring harness behind the radio.

ringo234

Spark plugs firing and other large voltage spikes can be picked up on the 12volt line. I just bought and installed a Pioneer AppRadio2 and it comes with a noise filter and doesn't effect the sound quality to my ears at least.

zenish

i put a ground lug on one of the bolts that hold down the automatic shifter.