Noise coming through speakers - Help Needed - Page 2

tbird2340 · 09-11-2004, 09:54 AM

OK.. I just hard wired my Lilli to my PW70A and tossed the Egg. It got rid of A LOT of the noise but at high volumes I still here some. I can here the hard drive when the PC boots up through the speakers.

I tried attaching an O ring to a wire and attaching that to a screw on my motherboard and then the other end to my grounding point. When I tried booting up after that the PC came on and then immediately shut off. Scared that I jacked something up I removed that ground on the motherboard screw.

I'm back to still having some noise but not as much.

Could it have anything to do with my switched wire on my ITPS? I have that hooked up to my blue wire on my HU (remote amp wire).

Thanks for the help!

euro320i · 09-13-2004, 08:24 AM

Does your noise rise with your engine RPM? If not it also may be the quality of cable. My noise was a steady brummmm.... It was a cheap pair of RCA cables. Any progress so far?

tbird2340 · 09-13-2004, 08:27 AM

It's so weird... Since I hardwired the Lilli the noise has gotten lower but it's still there. It didn't change with the engine. Yesterday I added a USB Wifi card (along with a USB cable) and now the noise changes with the RPM's. Everything is grounded in one spot. My ground wire is a very thin gauge wire though. It's prolly like 18-24. Do you think that could be it?

antimatter · 09-13-2004, 04:28 PM

Hey man you should really do some reading on engine noise... Just look it up in google. Type in alternator noise or ground loop. Go the the12vlolt.com (<- i think thats right check the techncal website sticky)

tbird2340 · 09-13-2004, 08:25 PM

One of the things I read was to run RCA's and your power/ground wires on opposite sides of the vehicle. Since this isn't possible in my truck it also suggested to run them crossing over each other instead of parrallel. I have a question about this though...

If I ran my RCA's in a piece of PVC would that work in eliminating the problem of running them parrallel. That's the only way I can run them.

Thanks

timothy0605 · 09-17-2004, 06:40 AM

You said you heard the HDD through the speakers. That is the kind of noise i get from some mobos with crappy onboard sound. Did you say this same noise happens with the pc off still?

Also, what prevents you from running the RCA opposite side than the power wire?

tbird2340 · 09-17-2004, 06:51 AM

The main problem at this momment is alternator whine. I can hear the whine change as my RPM's go up / down. It's getting to where I can't stand it but need to find time to try something..

I'm going to try a 10AWG ground. Currently I have a VERY thin ground. 18-24AWG. I'm not sure exactly what gauge it is I just had it laying around..

Also, your supposed to run the power/ground as far away as possible from the RCA's but with my setup this isn't realistic. Are there any solutions for this? Can I run one set of the wires in a PVC tube? Would that help?

wonderworm · 09-20-2004, 04:10 AM

I believe that there is a method to wrap your soundcard or even onboard sound in foil or something like that to block interferences and static. This should help with hard drive noise and other noise when the car is off. If someone knows exactly what you do, please post.

I have no alternator whine, but I do have some HD static and also I think I'm getting static from my USB GPS receiver as well. I use onboard sound for now.

tbird2340 · 09-20-2004, 06:55 AM

Well I tried a new ground wire. Ran 10 AWG and still have the same exact problem. I have both alternator whine and hard drive noise. This blows..

euro320i · 09-20-2004, 08:12 AM

Try this with a digital multimeter, measure the resistance from the NEG of your Radio to chassis. Then from the NEG of your power supply to chassis. They should be the same. IF not try tying to the same ground for both PC and Radio. I had a problem with sound, it was the bloody fuel pump that was humming thru the radio, only on the front line output pair... figure that!!

IonDokk · 09-20-2004, 11:44 AM

Your problem is probably in the type of ground you are using. I also had this problem and I went to the audiocontrol Three.1 indash preamp which allows me to define the type of ground I use... via Isolated non isolated or simply grounded it also will let you decide if your RCA's are directional or non directional. hope this will help. Computers and high end audio is tricky!

tbird2340 · 09-20-2004, 12:13 PM

Well I guess that doesn't really do anything for me.. I won't spend $250 to get rid of noise... Thanks for the reply though.

sq_geek · 09-20-2004, 10:22 PM

tbird- I'm having the same EXACT problem. My noise is there even when my PC is not even on!! It's not alternator whine, though -- it's just background noise ("static").

My noise only occurs; however, when the PC is plugged in (not on though) through the ITPS (which comes from the distro block from the battery for my amp) and also comes from the LCD when the power cable is plugged in (again NOT EVEN ON) which is plugged into my cigarette lighter currently (probably tied into accessory).

I need to try a separate battery, but I'm pretty confident that will solve the problem, because this only happens when my engine is on -- and with a second battery, it would be isolated enough (I hope) that sound couldn't "get in"...

I need to play around more with measuring resistance -- like what someone else said..

euro320i · 09-21-2004, 02:50 AM

Have you tried a higher quality RCA cables? Perhaps the ones with twists in the shielding??

tbird2340 · 09-21-2004, 08:37 AM

Hmmm... I wonder if they make the kind I actually need.

I bought this deck:

which has AUX input. I then had to get three cables. This one:

which plugs into the sound card in the PC. Then this cable:

Plugs into the RCA jacks of the first cable. Then yet another cable:

plugs into that one which in turn plugs into the head unit.