Noise/Buzz in audio Please Help

smhussain · 12-30-2008, 02:19 AM

I have connected my motherboard directly to my cars auxillary in. If i connect an mp3 play with aux there is no distortion but as soon as i connect the motherboard the buzzing starts. Which increases with engine rpm. I have read a lot of threads but people facing these issues have much more complicated systems then i have.

I have installed my pc in Glove Box of my Car. i do not have any amp or inverter. The pc is very simple:

Intel g945gclf2 mobo
m2-atx power supply
hard drive

Can somebody tell me what can be the source of this noise. I have only grounded my psu via provided cable to my battery.

Do i need to ground my mother board as well. If yes, How.

Do i need to ground my hard drive. If yes, How.

Thanks

dMand · 12-30-2008, 02:32 AM

With the little info that you provided, I can only make an educated guess that the "noise" ought to be coming from your speakers. Could it be a wasp nest or the neighbor's headboard banging on the drywall as they get their groove on?

Elaborate and enunciate with diction in reference to the noise you are experiencing so that we can better assist you. Give us more details.

I thought i'd give you a good chuckle before I answer your question. Google "ground loop isolator." Hope that helps.

Bet wishes and Happy Holidays!

~David

smhussain · 12-30-2008, 02:43 AM

If i mute my pc then i hear a constant "hissssssssssssssssssssssssssssssss" coming from speakers even when the engine is not running.

As soon as i start running my engine the "hissssss" is complimented with a very slight "Zoooooooo" sound which increases with increase of rpm. Kind of cool but mostely irritating.

dMand · 12-30-2008, 02:46 AM

Maybe a rattle snake found its way behind the door panel? I'm just being sarcastic...anyway, are you using an inverter in your car? If so, how is it grounded?

A ground loop occurs when there is more than one ground connection path between two pieces of equipment. The duplicate ground paths form the equivalent of a loop antenna which very efficiently picks up interference currents. Lead resistance transforms these currents into voltage fluctuations. As a consequence of ground loop induced voltages, the ground reference in the system is no longer a stable potential, so signals ride on the noise. The noise becomes part of the program signal making the "Zoooooooo" sound which increases with the rpm.

Are you putting a strain or heavy load on your car's electrical system? It may also be that it's trying to keep up with the demand and that your battery is living on the edge of failure.

Use a multi-meter to test across the battery, tell us what voltage are you reading with the car off, and with the car on.

smhussain · 12-30-2008, 03:20 AM

please read my first post. I do not have any special equipment. No inverter, no amplifier. My setup requires very low wattage so i don't think it is battery issue.

dMand · 12-30-2008, 03:31 AM

I obviously overlooked the the fact that you don't have an inverter, my bad.
Do you have a ground loop isolator installed in your system? If not, I suggest you install one. That may very well alleviate the noise you are hearing.
Also the motherboard should be installed on a metal plate properly with stand offs so that it will ground correctly with the other associated parts that were installed.

Keep your ground wires together on one connection when possible, no shortcuts.

smhussain · 12-30-2008, 03:39 AM

My motherboard is installed in the glovebox (which is plastic). So how can i ground motherboard. Can you please tell. Thankyou for your help.

dMand · 12-30-2008, 03:45 AM

is the motherboard mounted on a metal plate or is it inside a computer housing or case?

If none of the above are true then, I'll be the first to tell you, you will end up with a lot of noise issues along the way. Some of which are very hard to troubleshoot in an elaborate setup when worse comes to worse.

As stated in my previous post, the motherboard must be mounted properly using standoffs attached to a metal chasis. Otherwise, you may end up having to ground all of the screw points that are supposed to secure the board.

Furthermore, taking a shortcut by incorrectly attaching wires to the screw points without soldering them and then placing the board on a plastic surface will only make your situation worse.

smhussain · 12-30-2008, 03:53 AM

My motherboard is mounted with help of three screws to the glovebox. So should i ground all these three screws with negative of the battery.???

dMand · 12-30-2008, 04:10 AM

if it takes for you to accidentally zap your mainboard to learn and heed what I just explained to you TWICE then knock yourself out.

this concludes my assistance

smhussain · 12-30-2008, 04:14 AM

No...No...don't go away

is grounding motherboard safe.....should i ground it with negative of battery or just any metal surface.....can i run three separate wires from all screws and join them together at negative terminal of the battery.

dMand · 12-30-2008, 04:28 AM

Quote: Originally Posted by smhussain

No...No...don't go away

is grounding motherboard safe.....should i ground it with negative of battery or just any metal surface.....can i run three separate wires from all screws and join them together at negative terminal of the battery.

you don't need any help on the PC you need it elsewhere, all the info to help you is already posted here.

smhussain · 12-30-2008, 04:33 AM

I have to mount my motherboard without case in the glove box.

So what are my options. What am i not getting here. Please tell me. It will take a little time to write in detail but will eliminate any further questions from my end.

Just tell me what is the appropriate way to mount motherboard without casing and i shall do accordingly.

dMand · 12-30-2008, 04:44 AM

honestly, are you really that ignorant or just hard headed?

Your computer is likely to be the most expensive and most delicate part. It belongs where it was designed to be: inside a case.

smhussain · 12-30-2008, 04:50 AM

honestly what is with all the attitude. If you are all that knowlegable why not just reply to what was asked in the first place instead of going on with this big charade.

If you mean to be this arrogant why do you even come to forums which is usually full of noobs like me.

and btw, what is wrong with installing a computer in glove box. Many people have done it. I just wanted to ask what is the right way to do it. If you don't know, stop giving me crap.

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