Thread: CarPC Installed... Need some help.

The hum/hiss is almost certainly a ground loop, and the second inducted noise. The third is a pop from either the head unit or other pre-amp losing power and spiking through the system to the amps.

These links may be of some use.

Induced noise/Ground loop trouble shooting guide.

http://www.mp3car.com/vbulletin/gene...capacitor.html

^partially correct. hissing is sometimes caused by ground loops, though in pc's a more common cause is amp gains being set to high(are yours higher then half?) or a poor output stage on the pc's audio.

the humming is definitely a ground loop--so refer to the thread cabe linked to and post if it don't work out

the speaker pop could be a couple of things-i'll start with this though- if you are using the amp delay on the m2 to turn your amps on when the carpc turns on, this could be the reason that you do not hear it when all the equipment first turns on. ie: the 'pop' is always there, but the delayed output of the m2 is turning the equipment on after it occured, so you don't notice it..

Originally Posted by soundman98

^partially correct. hissing is sometimes caused by ground loops, though in pc's a more common cause is amp gains being set to high(are yours higher then half?) or a poor output stage on the pc's audio.

the humming is definitely a ground loop--so refer to the thread cabe linked to and post if it don't work out

the speaker pop could be a couple of things-i'll start with this though- if you are using the amp delay on the m2 to turn your amps on when the carpc turns on, this could be the reason that you do not hear it when all the equipment first turns on. ie: the 'pop' is always there, but the delayed output of the m2 is turning the equipment on after it occured, so you don't notice it..

The hissing was there before I put the PC in. Even when I don't have anything plugged into my audio processor before my amps, the hiss is there. The alternator whine is not though, that started after the carpc, so I will move my cables to the other side of the vehicle, away from the power cable. My speaker cable for my passenger side runs right along with the power cable, but the hiss is equal on both sides of the vehicle.

I do not have the amps switched from the M2-ATX, they are switched from the fuse box at the same fuse as the carpc. Should I run the 12v switch from the PSU?

The pop doesn't occur when the vehicle is started normally. It only happens when I am in auxiliary, and everything is on (audio components and carpc), and THEN I go to start it. Since both the carpc and audio components are powered off the battery, is it the 12v switch that is turning everything off and back on abruptly? Should I put a capacitor on the 12v switch? Will that fix the issue?

a important question i missed: does everything share the same ground point? sometimes having the pc grounded somewhere else can cause a gl.

check your grounds first, moving cables around in the car is more of a pain then trouble shooting the connections

switching the amps with the m2 might correct the pop issue, but it might also cause more issues-- the m2 is notorious for not having enough power to turn on some amp setups..

i am not sure a cap is a good idea. though, at the moment, i don't have any better solutions..

Originally Posted by soundman98

a important question i missed: does everything share the same ground point? sometimes having the pc grounded somewhere else can cause a gl.

check your grounds first, moving cables around in the car is more of a pain then trouble shooting the connections

switching the amps with the m2 might correct the pop issue, but it might also cause more issues-- the m2 is notorious for not having enough power to turn on some amp setups..

i am not sure a cap is a good idea. though, at the moment, i don't have any better solutions..

The CarPC is grounded at a different location than the amps and processor. I know the grounds are good, I made sure that they are on bare metal.

try grounding the pc to the same location as the other equipment-- this will sometimes fixt it..

you can also try grounding the negative part of a rca jack to 'drain' the noise out of the audio system-- sometimes it works, sometimes it adds noise, so be prepared to pull it off right away..

Originally Posted by soundman98

try grounding the pc to the same location as the other equipment-- this will sometimes fixt it..

you can also try grounding the negative part of a rca jack to 'drain' the noise out of the audio system-- sometimes it works, sometimes it adds noise, so be prepared to pull it off right away..

I've been hearing that I should ground it separately from the other components. Grounding everything at the same place might be tricky... If not close to impossible. What gauge wire should I be using? I'm using 4AWG for my amps, and 16AWG for everything else. Should I use thicker wiring?

definitely. i would recommend at least 12ga, if not 10.

you don't need to permanently ground it at the other location, just get a length of wire, and temporarily ground it to the other spot to see if it makes a difference in the audio..