Electrical interference and sound devices on computer?

Discussion in 'General Electronics Chat' started by sgtmattbaker, Oct 13, 2009.

  1. sgtmattbaker

    Thread Starter New Member

    Oct 13, 2009
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    I am having a lot of issues with EMI and my sound card (and onboard sound). I know this is the community discussion forum but I like this forum and there is likely to be someone that can help here.

    I have an Intel Core 2 Duo E6600 overclocked to 3.15GHz (I don't think I over-volted it, and I think I was having these problems before I did that) an asus p5b deluxe wi-fi AP edition, a geforce 8800gt 512MB and a soundblaster audigy 4 (not pro). When I have my 5.1 speakers plugged into the sound card I get an EMI sound through the speakers and subwoofer if I turn the woofer up more than halfway. The emi is more noticeable in the subwoofer. If I plug a microphone into the pink mic slot it makes a terrible, almost deafening sound (if the microphone itself is turned on). If the microphone is plugged in but turned off it does not. However, if I plug a microphone or another device into line in there is no such issue. To complicate things more I was trying to use gnuitar for effects for my bass and when I turn that program on it amplifies it terribly and I have to close the program.

    I tried using the onboard audio for the speakers and I don't get much EMI that way (I can turn the woofer and speakers all the way up and there is no noticeable sound for the most part) but there is still some. There is a very slight, almost imperceptible hum when running gnuitar and every now and then I hear a little bit of something if I am writing something using my wacom tablet. I can plug a normal microphone into the onboard along with the speakers and I do not get the terrible interference; however, if I use the stereo array mic that came with the motherboard it produces that sound. Also, for some reason when I tried playing one of my games (Batman: Arkham Asylum) the sound was really off. I could barely hear the voices in the game (and sometimes not at all) but all the other effects were as loud as they normally would be.

    I tried using the audigy 4 as the recording device and the onboard for audio playback but even with nothing else plugged into the audigy the mic port gave off an awful EMI hum or buzz (I don't exactly know the difference).

    So:
    audigy 4 has noticeable EMI for speakers and unbearable with microphone in mic port. line in does not do this. Cannot use gnuitar or rakarrack without terrible EMI.

    onboard audio has very little EMI with speakers (although I would like not to notice it at all) and none that I can tell with a normal mic but the array mic is unbearable. The sound is also messed up somehow in games (perhaps I had it set to 2 speakers instead of 5.1, but that wouldn't be the case unless the auto device recognition did that itself upon reboot). Can use GNUitar with onboard (haven't tried rakarrack as I have mainly been testing in Windows XP).

    So basically I want to know how to get rid of this terrible EMI. I want to be able to use my audigy card as the recording device and the sound device without EMI on the speakers (normally or using a guitar effects program). It would also be nice to be able to use the microphones I own. If the onboard audio worked well in games and in Ubuntu, as well as working with the array mic, then I wouldn't worry much about it. However, I did pay about $70 for the sound card a few years ago, and assuming it has its own special devices on it to control audio, I would prefer to use that. Another reason I want the sound card to work is that I have heard that having a dedicated sound card can take some stress off of the CPU in gaming.

    Note: my PC tower is an apevia aspire xpleasure and is partly aluminum and partly plastic (the front bay is plastic). It is sitting on carpet but stands a bit off the ground due to its legs.

    Thank you.
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    Ground loop between the computer and external equipment. Try plugging the AC cord on the external equipment into the same plug where the computer gets it's AC. If that doesn't help, try a ground loop isolator. I have had to do this to get the audio to and from my sound card into my ham equipment.

    Here is some reading about Ground Loops...
     
  3. Thav

    Member

    Oct 13, 2009
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    It doesn't seem like you have this in your setup, but another common cause of ground loop hum is when you connect a PC sound card and TV to the same stereo receiver. TVs typically use antenna ground, which is from the coaxial cable that connect to the rear of the TV, rather than your AC power ground.

    This is merely for reference if anyone else has a similar problem with an A/V setup.
     
  4. Audioguru

    New Member

    Dec 20, 2007
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    <snip>

    pad, pad, pad
     
    Last edited by a moderator: Oct 27, 2009
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    Not a show stopper. I'm running two sound cards from separate computers through an unshielded plastic switch box (DPDT toggle) to my ancient AR-1500 amp. There is not even a hint of noise of hum. The AR-1500's only modernization is a grounded power cord.

    The amp is on a wall outlet and the computers are powered through a UPS.

    The OP's issue may be with PS to case grounding. Or a horrible ground loop.
     
  6. sgtmattbaker

    Thread Starter New Member

    Oct 13, 2009
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    Power supply to case grounding you say? What exactly would you say that is? How would I test and fix that?

    Regarding the ground loop isolator, where would I place that? I am assuming that it would connect between the speakers and the subwoofer but there are three speaker ports and the mic port on my audigy that are acting up. Am I going to have to buy two of these things? I am assuming that if I want to use my mics I need one isolator with a female in and a male out.

    Also, I didn't say this, but there is a wireless g router about 8 feet away from the computer. However, I wouldn't think it would be a wireless interference issue since the onboard sound isn't having any humming issues.

    I have all my electronic devices plugged into surge protectors. The external hard drive, PC, monitor and subwoofer are plugged into the same one.

    What would be the case if I used one or two of those ground loop isolators and they didn't do anything? Is that possible?

    Thanks.
     
  7. t06afre

    AAC Fanatic!

    May 11, 2009
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    This is a somewhat futile comment. The serious sound cards manufactures know very much about audio related problems. As they know their sound cards will be tested and evaluated by independent magazines etc. But as always quality cost some money. If you buy a very cheap sound card from a unknown manufacturer in China, you will probably get a "noisy" sound. But sound cards in the midrange price range are often quite good.
    I am quite sure that sgtmattbakers problem is related to the cabling, and perhaps ground loop. It may also be that your input level is to high so your signal is heavily distorted then using the microphone input.
     
    Last edited by a moderator: Oct 27, 2009
  8. sgtmattbaker

    Thread Starter New Member

    Oct 13, 2009
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    Could anyone answer my questions from my last post? I just don't understand what is going on.

    I bought a refurbished Dell D600 and brought it in my room to work on it and I got this terrible EMI sound from it too! This was 6 or 7 feet away from the other computer and it was off. I then moved it 7 feet away from the PC in the opposite direction and it got louder. I turned off the wireless router and turned off the fluorescent lights in the room and it still didn't go away. Nothing else in the room was on. I switched from Ubuntu to Windows XP and the EMI was not present, so I am thinking it may be the way Ubuntu handles the audio or something. It still doesn't make any sense to me though because it wasn't doing it upstairs.

    Regardless, all these EMI sounds are very annoying and I don't know why this is happening. Is there something in my room that just does that to things? I would really prefer not to have to move all my stuff out of the basement just to fix all these crazy audio issues.

    AARRGH!
     
  9. beenthere

    Retired Moderator

    Apr 20, 2004
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    One variable not associated with a computer but common to all is the house wiring. I might wonder is you have grounded outlets, and if they are properly wired?
     
  10. Audioguru

    New Member

    Dec 20, 2007
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    There is no such thing as EMI audio. Please describe it completely if it is hum or buzzing noises.

    Of course the input wires are shielded audio cables?
    If they are not shielded then the wires pick up mains hum and dimmer buzz.
     
  11. Thav

    Member

    Oct 13, 2009
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    Some cell phones getting calls can cause interference with nearby speakers. You would hear it as a series of quick buzzes that would subside in a few seconds. Is your problem intermittent or constant?
     
  12. sgtmattbaker

    Thread Starter New Member

    Oct 13, 2009
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    Scratch the laptop problem. That does it regardless of where I am in the house. It happens if the volume in the OS is turned up more than halfway. I think it is just crappy onboard audio (the computer was said to be refurbished when I bought it).

    I think I am getting buzzing and humming. With the speakers in the audigy4 the speakers buzz, but if I turn the subwoofer up higher than 1/3 of the way it starts to hum. If I keep the subwoofer turned down it is barely noticeable but if I run any sound effects program (like a software effects pedal for a guitar) it produces what sounds like a very loud screeching/humming noise. When the program starts it gets gradually louder and after a few seconds it is extremely loud and muse be turned off. I do not get it with onboard sound (I can turn my subwoofer all the way up without hearing anything; the onboard sound doesn't seem to be playing all the sounds in my games so I can't just use that and forget about the sound card).

    If I plug a mic into the onboard with the speakers there it doesn't do it unless I am using the array mic that came with the motherboard (so normal mic is fine). If I put any mic into the mic port on the audigy it produces the interference. I don't know if something has to be plugged in somewhere else or not. I did try the speakers in the onboard and the mic in the audigy and that produced the interference as well. The screeching kind of sound is happening with the microphones.

    When you ask about shielded cables what exactly do you mean? The cables that connect to the PC are audio cables with the black wire covering that is seen on most wires. Are you asking if the wires have foil wrapped around them, like my ethernet cables do?

    Thanks for your help everyone.
     
  13. sgtmattbaker

    Thread Starter New Member

    Oct 13, 2009
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    If anyone has any suggestions or thoughts on what is going on please help? Do you think my motherboard and/or sound card is going bad/causing issues? Everything else seems to work fine.

    I guess I can try powering the computer down, removing the sound card, putting it back in the PCI slot and making sure it is seated correctly. I can also try one of the other PCI ports although I think the only other available one is right next to the GPU so it will get hot.

    I have gotten some suggestions here but wanted to know what this board thought of them: http://ubuntuforums.org/showthread.php?p=8099366#post8099366

    I don't want to have to do something really drastic and risk borking my board, sound card or my computer as a whole.

    Thank you.
     
  14. soda

    Active Member

    Dec 7, 2008
    174
    13
    Hi
    Cut a peace of thin flat metal sheet the size of your sound card and wrap it with plastic or pvc. Make sure the sheet is fully wrapped. place it on the sound card. That will remove any hum and noise.

    Soda
     
  15. sgtmattbaker

    Thread Starter New Member

    Oct 13, 2009
    9
    0
    I appreciate the help but why would I get interference from both my sound card and the onboard sound (even though the interference only occurs on the onboard sound when the array mic that came with the motherboard is plugged in; the regular mic works)? If I were to put a piece of something on the soundcard the interference would still be there from the other wouldn't it? If that is the only way to fix it then I suppose I could do it but it annoys me that I have to fix the issue in such a home-made and inconvenient way.
     
  16. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    That will never help - the sheet has to be at least grounded.
     
  17. sgtmattbaker

    Thread Starter New Member

    Oct 13, 2009
    9
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    Does anybody have any do-able ideas? This is very annoying.
     
  18. BMorse

    Senior Member

    Sep 26, 2009
    2,675
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    Your 5.1 system should be connected to your PC's speaker out port and you have to set the line out to stereo speakers, not 5.1. If you set it to 5.1 your outputs (on the motherboard) will change according to your setup.... (i.e. you will have to connect separate speakers for left/right/front/sub etc. But most likely all other speakers connect to the sub and only the sub has inputs from the PC right?

    What model/Make is your motherboard??
     
    Last edited: Oct 24, 2009
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