Wining sound only when car in motion

**migitcheetah** · 08-10-2009, 07:25 PM

hi, im sure its been posted about the wining sound, but i cannot find one that solves my issue specifically.
i have a wining sound that only appears when mi car is in drive, and moving. it doesn't appear when im parked, whether the car is on or off. and doesn't appear when im in gear holding the breaks, only when i move.

here is my setup.

i have my car pc with on board sound connected to mi head units av input, then the head unit goes out to mi amps.

when i listen to a cd threw the head unit their is no wine, so i know its from the pc. ive tried rewiring it, and tried ground loop isolators, but still get it. does anyone know of a solution. or have a way to make it low enough to not hear. ive plaid with the gains, but i have enough ams and speakers where even with the gains lower it gets loud enough where when the music stops you hear a loud wine. low volume has a real soft wine that is bearable, but loud volume is annoying.

please help if you can.

**migitcheetah** · 08-10-2009, 07:36 PM

well i think i might have solved it. i dont know how it worked but i wired up 3 ground loop isolators i had lying around together and hooked them up to the pc line out and took a quick drive and it seems to have solved the problem. but still if anyone knows of a better way or a more secure 100% way let me know. and ill let you know later on if it really worked or if it was just being nice to me for a minute.

**soundman98** · 08-11-2009, 08:43 AM

this would be a ground loop-- yours will be the third recent thread on it

. if the ground loop isolators work, and you are happy with it, then good job, and happy car computing!

for me, i can't stand the idea of putting a bandaid on the problem(the ground loop device) so i feel compelled to find the source of the GL. it can be caused by many things-- from a faulty power supply, or simply a good power supply, but one that creates noise(the m2 is notorious for noise issues, so if you have one, you can try shielding it, or moving it away form everything else) to having more than one device grounded at more than one location in the car.

because the ground loop can be caused by so many different things, or a combination of any of them, almost every GL in every install is different, so if you choose to trouble shoot it any farther, check some of the other threads in this area for some trouble shooting tips that you can try.

(sorry for the long post, while i was typing, i was also trying to figure out my own ground loop problems)

**migitcheetah** · 08-11-2009, 01:11 PM

thank you. i do want to try and find the cause, i just put the isolators for now so i dont have to hear it, but i will be investigating to find the culpret. i have an M4 and im asuming they are the same as the M2 in the noise. and it could be because i havent ran my power and ground in the final spots, their just laying ontop of things, but i need to buy longe rwires first. but if you know maybe you could help. are the M4's noisy too. because if they are i bet thats what it is just the way mi wires are laying on other things.

also, what do you mean by shielding. put a case on it, or what.

thanks so much

**sergatiuk** · 08-11-2009, 01:18 PM

what do you use to deliver power to the PC ?
PSU ? inverter ?

**migitcheetah** · 08-11-2009, 01:22 PM

its a M4-atx powerfully connected directly to the car battery.

**sergatiuk** · 08-11-2009, 01:24 PM

the amp must be connected to the same ground, is it ?

**migitcheetah** · 08-11-2009, 01:26 PM

no they all have their own ground. but at the moment the power to the pc is laying on one of the amps because the cable isnt long enough for me to run it how i want it.

**sergatiuk** · 08-11-2009, 01:31 PM

their own ground is not good... every device on your setup must have the same ground source, either bat or chassis
try this....
ground the amp, PC to chassis, at the same point. ground the PC case to chassis as well.
if stiff doesnt work, take the wire harness from the PSU to the Mobo and add another wire to the ground and attach it to the chassis as well.

**migitcheetah** · 08-11-2009, 01:40 PM

well they are all grounded to the chassis by bolts. and they are next to each other. all my amps have their own ground and they work fine. why would i need to ground the pc with them. is it just how it works. shouldn't it work just fine in its own ground. they have the same ground source. wich is the chassis, but they each have their own bolt on the chassis.