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monitor noise.. room electrical problem?

Discussion in 'Recording' started by seventhwave99, Sep 2, 2007.

  1. Hi all. I just recently purchased a pair of yamaha hs50m's which I'm using in conjunction with my focusrite saffire firewire audio interface. To make a long story short I was getting some dreadful noise through the monitors. When I unplug the power supply from my laptop and run from battery power, the noise dissapears completely and my entire system is functional.

    I don't want to run off battery power when working on projects.. I tried to run my laptop cord out to another room to another power source and what do you know.. no noise. Tried another room's outlet.. no noise. back to any of the outlets in my room, and there's enough noise to make your ears cringe. I've tried distancing certain items in my chain.. laptop, sound card etc from my monitors which has no effect on the noise. It dissapears when I plug into another room's outlet.

    I don't have a HUGE problem running an extension cord for my laptop's power.. but that would be a less elegant and more temporary solution than I would like.

    Does anyone know enough about electrical setups to give me some options? I'm at a loss and ideally I'd like to keep my studio self contained within the room. Can i affect the power in some way before it gets to the room? Can I purchase some kind of power conditioner, would that apply in this situation? Can I have somebody look at what may be a poor electrical job and do some rewiring?

    Anything you folks could throw at me to consider would be a breath of fresh air. Cheers!
  2. Link555

    Link555 Well-Known Member

    Sound like you may have a ground loop issue in your building wiring. These can be tricky, to fix. is there anyway you can verify the wiring is correct? neutal should return to ground at the panel.

    If the wiring is correct and the noise is still there on that oulet->

    then Try an isolation transformer.


    also you could try some supression circuits like:
  3. Boswell

    Boswell Moderator Distinguished Member

    I think it's likely that the power supply unit for your laptop is putting high-frequency garbage back into the mains, which is then travelling round the mains circuit and into your other audio gear. It could be that the other rooms are on a different mains phase and there is sufficient non-coupling between phases to suppress the noise.

    You could indeed experiment with isolation transformers, mains filters and the like, but I would recommend trying a higher-quality power supply for the laptop.
  4. Link555

    Link555 Well-Known Member

    Switching power supplies, you have to love them.
  5. As someone with zero electrical experience, should I call an electrician to check the ground loop of the building or can I do some research and attempt it on my own. Looks like I have some homework to do, after that point I think I'll try the transformer. Excellent options, I will explore them all in good time and hopefully one lands me where i want to be. Thanks to both of you for the insight. Should any more ideas strike you in the middle of the night, don't hesitate to post them lol.

    Thank you.
  6. Boswell

    Boswell Moderator Distinguished Member

    Check your laptop power supply, but my guess is that it has a 2-pin mains connector on it, not 3-pin, so no ground connection, and therefore ground loops do not come into the equation.

    I think you ought to try to get another power supply of a different and better make.
  7. VonRocK

    VonRocK Active Member

    Do you have a dimmer switch?

    Always pointing out the obvious, just in case.
  8. By the number of pins you mean how many prongs on the cord right? (laymen here, beware) there is a third pin for ground.. so that wouldn't be the problem. The power supply being criminally cheap, however, is a definite possibility. Some further details to my problem..

    During cpu usage the sound will fluctuates and sometimes disappear for a short time while minimizing windows or opening programs etc. So the noise is in some way tied to the cpu whether that means when it draws upon the cheap power supply I get the noise, or perhaps when any power supply draws upon the faulty wiring inside this room it leaves me with these results.

    I don't have a dimmer, but I do have a ceiling fan. I've tried different combinations such as fan on, light on.. fan off light off, and everything in between including different speeds and that doesn't seem to affect the situation in any way.


    Should have been an electrician instead of an engineer perhaps? Then again how would I feel to sit down to a fully functional project studio and not know how to record ready my tracks lol.
  9. Boswell

    Boswell Moderator Distinguished Member

    I meant the power supply end of the mains cord, unless it's permanently attached, in which case look to see if the cord is obviously 2-wire.
    Clues here. The laptop is pushing processor-related noise into the power supply. The noise, being high-frequency, goes straight through it and into the mains. A good supply will fix this.

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