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Thread: On board soundcard sounds aweful!

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    Question On board soundcard sounds aweful!

    Got an Intel d525mw. It's supposed to have a good soundcard but it sounds like crap. Lotta noise. I verified the rest of the system is good with no noise 'cause my kids PSP plugged into the amp sounds great. Just a question... is this common and do most folks use external sound cards?

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    MySQL Error soundman98's Avatar
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    what kind of noise? like a whining/buzzing? that is a ground loop. there are a couple threads on how to fix that.
    Last edited by soundman98; 10-05-2011 at 10:03 PM.

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    Quote Originally Posted by soundman98 View Post
    what kind of noise? like a whining/buzzing? that is a ground loop. there are a couple threads on how to fix that.
    It's definitely comming from the computer. I checked everything past the computer and it all looks good. When I drive my amp with any other source (kid's PSP), all the noise goes away. I've got both buzzing and whining. Whining of course changes frequency with engine speed (alternator whine) and the buzzing is not as bad when the engine is off.

    I've tried both a gound loop isolator between the carpc and amp and different RCA cables located well away from any power wires with no change... as well as grounding the audio ground.

    I will try running better/different ground wires and tie both the amp and carpc together.

    I do not have a filter on the 12 volt supplying either the carpc and amp but they are both powered directly from the battery. Do these really work anyway? I have a M2-ATX ps.

    Should I try an external USB sound card? I do have the computer quite packed with HQCT and some other odds and ends as well as a run of the mill HD. Could this be introducing the noise and if so, would this affect an external one?

    Thanks

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    MySQL Error soundman98's Avatar
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    i don't believe that a usb sound card is the complete solution, and i don't believe that any of the carpc components are the cause of this issue. it is simply a problem that sometimes crops up when installing a aftermarket device in a car(there are tons of audio forums that talk about the same issue with aftermarket amps)..

    there are threads on noise issues with the m2, but they mostly deal with high freq issues (out of the range of human hearing), where gps antenna's can't get a lock, or radio antenna's loose fm reception.

    you also do not require a filter on the m2, as the whole point of the m2 is to filter the power. i have seen some power ground loop isolators, but don't believe they will do any better at correcting the issue.


    a ground loop by definition is a voltage potential difference between 2 points-- meaning that something in the power/ground wiring for either the amp, or carpc(or other components) has more resistance then the other, so voltage is flowing between them to follow the path of least resistance-- you hear that voltage flow as 'noise'.

    you've already tried the easier stuff--those ground loop isolators(GLI) are sometimes hit-or-miss, but mostly a miss.

    1. the first and easiest thing to try is to check and recheck your power cabling-- make sure that all wiring is correctly sized for the power it carries, and the ground wires have good clean metal-to-metal contact with the car chassis-- typically by choosing a good solid mounting point, and sanding the paint off that area. any paint between the ground wire and the chassis can cause the issue.

    2. if that doesn't work, try sharing the ground, by attaching both devices to the same ground point.

    remember-- newer cars are built out of sheet metal that is spot-welded together, which means that certain panels can have a higher resistance then other areas of the car, due to the way the weld combines the different pieces of metal.

    3. because of the above point, sometimes even putting the devices to the same spot won't fix the problem. you then can try a different spot all together.

    4. if all of that fails, you will need to run a new wire directly to the negative battery terminal. i recommend running a wire 1 step thicker then what is being used for the devices(remember wire gauge numbers get smaller as the wire gets bigger--so if you have 8ga run for power, run 4ga for ground).

    typically, one of these things should fix it, but there are no guarantees-- GL's are a fickle beast, and some are harder to correct then others.


    if you want to do some reading, i found a lengthy article on the subject:
    http://www.epanorama.net/documents/g...oop/index.html
    Last edited by soundman98; 10-05-2011 at 11:56 PM.

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    Thanks for the input. Will have a second look at the ground wires and I'll try running a wire from the negitive terminal on the bat and post my results. BTW... thank you for the article!

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    typically, one of these things should fix it, but there are no guarantees-- GL's are a fickle beast, and some are harder to correct then others
    Yep, wouldn't ya know that after running more grounds all tied them all together and connected them directly to the battery this didn't make a darn bit of difference (both the amp and pc grouned to the same point with this point connected to the neg side of the batt). I even made sure the carpc case was grounded (is this a bad thing?). One thing I failed to mention is I can hear what sounds like R2-D2 coming from the system??? Yea, some of the noise is all kinds of little beeps and such. This coupled with the fact that the noise coincides with the actions of the computer leads me to believe that at least some of the noise is from the computer. At least I hope so since this GL has me stumped!

    Thoughts?

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    MySQL Error soundman98's Avatar
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    i have heard of that before-- something about a ground loop can cause those 'r2-d2' noises. basically the hdd is sending data and it is getting picked up in the audio stream..

    i checked, and didn't see a worklog yet-- so could you post your carpc parts list? also, if you could provide some details of how/where the carpc is, and what type of wire was used, i hope i can find something in it all..

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    I assume the cable you used for the ground between the AMP and the PC and Battery was rated at 55A or more.

    Unplug the audio lead feeding your AMP from the PC output and touch one of the active audio terminals of the lead to the case of the PC.
    How much does the noise change?
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    Sure...

    IntelD525MW w/Atom processor 1.8GHz
    4 GB (2 x 2 GB) Kingston KVR1333D3S9 RAM
    250 GB Samsung SATA HD (2.5")
    M2-ATX PS
    VoomPC case
    HQCT-i
    MJS Gadgets Sat Radio interface
    Pioneer GM-3400T amp (yea, yea, I know but it was inexpensive)
    XP Pro and CF3.6

    Stock 2010 CRV with Optima yellow top deep cycle battery.

    The computer is installed under the driver's seat with power coming directly off the battery. LCD mounted in dash. Amp shoehorned behind LCD in the dash with power coming from battery as well. Both carpc and amp grounded locally with an additional ground connecting both units to ground lug behind drivers kick panel. This lug is also connected directly the neg side of the battery. All power and data running under drivers sill plate with the acception of the rca's. Amp remote turn on controled by carpc ps (M2-ATX). Amp wired with 12 guage wire. Carpc 14 guage.

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    Have you tried renewing the Radio Suppressors on the back of the alternator and or at the distributer( depends on the vehicle)? Most new car stereos/amps compensate for noises comming from the engine electrics and faulty suppressors. As soundman mentioned before. It all comes down to a ground loop and pc's/carpc's need a good ground/earth. Cars just have a very poor ground so pc's etc are more prone to noise signals. An earth strap under the vehicle may help when your at a stand still. And a noise filter on your audio line to amp will help too but i think you have allready tried with no success.
    Last edited by pcmoto.com.au; 10-07-2011 at 09:11 AM.

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