Noise

Discussion in 'Digital Audio' started by -igor, Feb 27, 2007.

  1. -igor macrumors member

    Joined:
    Feb 25, 2007
    #1
    Hello. I have a 20" Intel iMac, Firewire 410 and Rokit RP5 powered monitors. There is quite a significant amount of noise including the computer just simply being on, occasional random clicks and pops, the screen darkening, moving the mouse, scroling and a lot more. I definately see this as a conflict for recording. Is anyone else having this same problem? What is causing it? The computer? Are there quieter machines because I can still return it? Please help me.
     
  2. zimv20 macrumors 601

    zimv20

    Joined:
    Jul 18, 2002
    Location:
    toronto
    #2
    do you mean to say that activity on the computer (scrolling, mouse movement) is making its way to the speakers?
     
  3. -igor thread starter macrumors member

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    Feb 25, 2007
  4. zimv20 macrumors 601

    zimv20

    Joined:
    Jul 18, 2002
    Location:
    toronto
    #4
    it could be an issue with the wall power. is everything on the same circuit? if not, put them on the same. if so, try different circuits.

    if no luck there, it may be worthwhile to haul your kit to a friend's house, who seems to have decent electricity, and try it there. this is all in an effort to either isolate or rule out a noisy power source.

    if you can determine that it is indeed noisy, invest in a line conditioner.
     
  5. -igor thread starter macrumors member

    Joined:
    Feb 25, 2007
    #5
    my dad figured out it had to do with the interface being powered by the machine. I plugged in the power source and it's considerably better but still pretty noticeable. then he said it has something to do with the interface not being grounded while the machine and the speakers are. is this most definately a problem with grounding and circuitry? because then I will know whether I am pidgeon holed or not. thanks for the tips. I will try them.
     
  6. zimv20 macrumors 601

    zimv20

    Joined:
    Jul 18, 2002
    Location:
    toronto
    #6
    yeah, that should be under its own power. everything should be grounded and run off the same circuit.* if you've got, say, one of those 3-prong to 2-prong adapters so that you can run from a 2-prong circuit, lose that and make sure everything's grounded.

    also, don't make a mess of your power and audio cables. organize them such that the two types don't run in parallel. if they must cross, do so at a 90 degree angle and (if possible) at a distance.

    * to cma, it is possible to set up electrical in a studio to run just fine off more than one circuit, but that's out of scope for a small home project. so "run it off one circuit" it is.
     
  7. -igor thread starter macrumors member

    Joined:
    Feb 25, 2007
    #7
    thanks so much for your help! I am now running everything from one circuit but the noise is still there to a degree. the adaptor for the interface is a two prong one. and the problem is with the interface for sure. I turned off the computer and it is making a noise when it's plugged in to the computer. it seems maybe the power coming out of the computer to power the interface is it. is there a way to just cut off all power from the computer to the interface and have it powered completely by the power supply? I know the 6 pin firewire outputs don't power but my computer only has 8 pin ones.
     
  8. zimv20 macrumors 601

    zimv20

    Joined:
    Jul 18, 2002
    Location:
    toronto
    #8
    just so i'm clear...

    1. interface connected to monitors, computer "in box", everything is ok
    2. connect the computer, even with it powered down, and you get noise
    3. power up computer, noise remains and is basically the same

    is that right?
     
  9. Mydriasis macrumors 6502

    Mydriasis

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    Mar 17, 2005
    #9
  10. -igor thread starter macrumors member

    Joined:
    Feb 25, 2007
    #10
    what do you mean by "in box"

    there is a slight bit of high pitched noise when computer is powered down

    upon login the real noise I am talking about kicks in, that is, buzzing and the sound of scrolling/mouse moving/screen darkening. the hight pitched noise is also present. but no, it isn't the same at all, there is a huge difference.
     
  11. zimv20 macrumors 601

    zimv20

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    Jul 18, 2002
    Location:
    toronto
    #11
    i mean not hooked up to the interface at all. not literally "packed away into its box", but i want to know if the mere presence of the mac in the equation adds noise.
     
  12. chasemac macrumors 6502a

    chasemac

    Joined:
    Jan 30, 2005
    Location:
    In a house.
    #12
    Just some suggestions

    1. Try a different power strip or surge protector.
    2. Adjust the volume levels on the monitors themselves. I had some unwanted noise on mine and just turned them down and it solved my problem. You normally don't need them turned up very high, just use your interface to adjust the volume levels. I still have a slight noise from my powered monitors but it is hardly noticeable now.
    3. Make sure you have the proper cabling for your monitors. Review your manuals and try another pair from a friend if you can.
    4. Move your setup some where else in your home or apartment to see if you get the same results.

    Good luck,

    chasemac
     
  13. -igor thread starter macrumors member

    Joined:
    Feb 25, 2007
    #13
    I turned down the volume on the monitrors and hooked the interface to a power supply. I suppose I can live with it but there is still occasional pops and hiss.
     
  14. Fergtime macrumors newbie

    Joined:
    Nov 5, 2007
    #14
    It doesn't sound like that's HIS problem, but his describes EXACTLY what I'm experiencing. I have ordered a firewire hub to see if that helps. It may end up just passing the noise through, but I figure it's worth a shot.

    Is anyone else having this problem?
     
  15. ausdave macrumors member

    ausdave

    Joined:
    Aug 28, 2007
    #15
    I have the same problem with my Edirol UA-20 USB... lots of digital noises in the background.

    Also, but not as bad, is the output from the iMac itself (Al 24" 2.8).

    I was thinking of upgrading to a Terratec Phase 24FW audio interface:

    (http://audioen.terratec.net/modules.php?op=modload&name=News&file=article&sid=5)

    as I know that the Edirol is not that great to start with (have had it for years when i needed something portable with my laptop),

    Now i'm worried that I will have the same problem.
     
  16. Fergtime macrumors newbie

    Joined:
    Nov 5, 2007
    #16
    Well, I got the firewire hub, and it didn't help. I'm really torn. I know the device I'm using isn't that great, but I've tried with another firewire device, and the results were similar, which makes me think it's the Mac itself.

    I do have the applecare protection, so I guess it's time to give them a call.
     
  17. sblasl macrumors 6502a

    sblasl

    Joined:
    Apr 25, 2004
    Location:
    Heber Springs, AR
    #17
    I think Apple has problems with the AppleHDA.kext & IOAudioFamily.kext. These are system extensions. Problems began to occur with the 10.4.9 update and in many cases still exist to this day.
     
  18. WinterMute Moderator emeritus

    WinterMute

    Joined:
    Jan 19, 2003
    Location:
    London, England
    #18
    These issue are caused by poor shielding and earthing within the computer OR the interface, and can be exacerbated by running the output of the interface too high and the input levels too low.

    I run an M-box 1 powered over the USB bus into a MBP and/or an Intel iMac and I have no noise issues (if I don't overdrive the woefully underpowered mic amps that is).

    Try reducing the output levels from your interfaces main output to around 2/3 (or even 1/2) and then turn the monitors up, then make sure you use as much of the input gain as you comfortably can without distorting the input.

    This should maximise the signal/noise ratio at the input and lower the noise to the output.

    All Zim's advice still pertains in a project studio, but unfortunately you are suffering from poor power handling design.
     
  19. synth3tik macrumors 68040

    synth3tik

    Joined:
    Oct 11, 2006
    Location:
    Minneapolis, MN
    #19
    Make sure your interface is running the same frequency as the computer. 41k vs. 48k. I had an issue with an interface awhile back that liked to default to 48k when the computer and all audio from it was running at 41k. That could be the cause of your pops and clicks.

    As for the noise, it seems like you have gotten a few of the issues out of the way. Are you using the correct cables. i.e. interconnects and not instrument cables. Also, you don't need to spend hundreds of dollars on cables, but cheap cables will result in bad quality. And finally make sure that your audio cable and power cables are not crossing. try to separate them as much as possible to avoid line noise from the power.

    Oh and have the volume on the computer 8/10s up and 7/10s on the interface and keep the monitors volume low. This will reduce the noise from the drivers in the monitors.
     

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