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Help with noisy USB audio interface

Discussion in 'Recording Gear and Equipment [BG]' started by paulraphael, Jul 21, 2009.

  1. Jul 21, 2009 #1
    paulraphael

    paulraphael

    Apr 13, 2006
    Brooklyn
    If you heard me play, you'd stop reading what I write.
    I've been losing my mind trying to troubleshoot this. Maybe one of you geniuses can help.

    I'm using an E-MU 0202 USB-2 interface on my computer (PowerMac G4, OSX 10.4.11). I'm using it more for music playback than for recording.

    I get noise that ranges from the ocasional buzz and zap to loud backround crackle. Sometimes it even degenerates to total distortion, which repairs itself if I turn the device off and on.

    Here's some troubleshooting I've done:
    1) replaced the E-MU device. The store that sold it to me assumed it was defective and sent a new one. No change.
    2) replaced the USB-2 card. Things got worse!
    3) replaced the USB-2 cable. No change.
    4) tried different outputs on the device (line out to stereo, line out to powered speakers, headphone out). No change.
    5) compared to the Mac's built-in audio. This is almost perfect, although once in a great while I hear a buzz or zap. Of course, sound quality is low.

    Any thoughts?

    This audio interface draws its power from the USB port. There's no option for a separate power supply. I'm wondering if dirty power from the computer's power supply might have something to do with it. If this sounds likely I may try a powered USB hub.

    Thanks for any brainstorming.
     
  2. Jul 21, 2009 #2
    D.Don

    D.Don

    Mar 6, 2008
    Swede lost in the 5th republic
    You sure the usb thingie isn't sharing resources with something else?

    Sounds like something in that direction. I assume it has nothing to do with buffer size.

    D.Don
     
  3. Jul 21, 2009 #3
    paulraphael

    paulraphael

    Apr 13, 2006
    Brooklyn
    If you heard me play, you'd stop reading what I write.
    I don't think that's it. From what I gather, the only issue with USB resources if if you don't have the bandwidth available. At that point the port will just shut off.

    I have these problems even if I'm not using any other USB devices (the keyboard and mouse, which use insignificant bandwidth, are on the computer's built-in port, not the USB-2 card that powers the audio interface).
     
  4. Jul 21, 2009 #4
    John Wentzien

    John Wentzien

    Jun 25, 2007
    Elberta, AL
    Artist:TC Electronic RH450 bass system (original test-pilot)
    Make sure the unit isn't too close to your PC or monitor.
     
  5. Jul 23, 2009 #5
    paulraphael

    paulraphael

    Apr 13, 2006
    Brooklyn
    If you heard me play, you'd stop reading what I write.
    Did some more troubleshooting. Proximity to monitor, computer, wireless stuff, etc. isn't the issue.

    I hooked the unit up to another power Mac, and the problem went away. So it seems to be an issue with the computer.

    I'm wondering if it could have to do with dirty power from the computer's power supply. I may try plugging the unit into a powered USB hub, but i'd have to buy one ... does this sound like a reasonable idea?
     
  6. Jul 23, 2009 #6
    jkramer5

    jkramer5

    Jul 14, 2008
    Fairfield, CA
    Just a shot in the dark....

    Does the computer that makes the noise have a wireless network card on it? If so try disabling it.
     
  7. Jul 23, 2009 #7
    yamark

    yamark

    Jun 6, 2009
    Lancaster, KY
    i found that my issue came from my laptop power cord
     
  8. Jul 23, 2009 #8
    Auzzie-Phoenix

    Auzzie-Phoenix

    Mar 30, 2007
    Columbus, OH
    It's more than likely a driver issue and how the computer is handling them. I get a similar issue if I don't get a clean reboot (ie. after a fresh cold boot or crash). Creative makes great devices, but their drivers are terrible. Try another set of drivers or a clean restart (not a shut down/restart). I really can't be certain on this due to pc vs mac issue. But their drivers usually tend to be the culprit in most situations.
     
  9. Jul 23, 2009 #9
    jkramer5

    jkramer5

    Jul 14, 2008
    Fairfield, CA

    Glad ya found it. And now that you say what it was, I've seen similar on the forum for the company that makes my firewire interface.
    By power cord, you mean that when the laptop is plugged in to A/C voltage it creates the interference but running off the battery it doesn't? Rather than something was/is physicaly faulty with the power cord?
     
  10. Jul 23, 2009 #10
    paulraphael

    paulraphael

    Apr 13, 2006
    Brooklyn
    If you heard me play, you'd stop reading what I write.
    Don't think it's the driver ... worked fine with the same driver in a different mac.
     
  11. Jul 26, 2009 #11
    MIJ-VI

    MIJ-VI Inactive Supporting Member

    Jan 12, 2009
    - Did this card come with the audio interface?

    - Does your G4 have USB 2.0 ports?

    - Which PowerMac G4 do you have?

    - The USB audio interfaces I've seen all call for a fast G4 (or better) with built-in USB 2.0 ports.
     
  12. Jul 28, 2009 #12
    paulraphael

    paulraphael

    Apr 13, 2006
    Brooklyn
    If you heard me play, you'd stop reading what I write.
    It's not a card, it's an external interface that connects via USB-2. It works fine hooked up to the same usb-2 card in a different computer.

    The computer that's having problems is a dual 1.25ghz machine (it works fine in the other machine which is only 500 mhz).
     
  13. Jul 28, 2009 #13
    Kevmove

    Kevmove

    Jul 21, 2007
    You have a choice: buy an expensive replacement power supply, or go to Radio Shack buy a ground loop isolator. Works everytime.
     
  14. Jul 29, 2009 #14
    paulraphael

    paulraphael

    Apr 13, 2006
    Brooklyn
    If you heard me play, you'd stop reading what I write.
    How does a ground loop isolator work? And does it do somethring different from the ground lift switches on the unit itself (they have no effect)?

    By replacement power supply I'm assuming this includes a powered USB hub, which I'm thinking about trying. I don't believe they're all expensive.
     
  15. Jul 29, 2009 #15
    MIJ-VI

    MIJ-VI Inactive Supporting Member

    Jan 12, 2009
    Hmm... Apple Power Macintosh G4 1.25 DP (MDD) Specs (M8573LL/A)
    The last & fastest of the OS 9.2.2-bootable Macs. Nice machine! :)

    Have you tried your USB card in different PCI slots? (The ol' card shuffle is sometimes what it takes to get things working.)

    Which make & model of USB PCI card do you have?

    Are you using other PCI cards as well? If so, you may be straining the power budget for your Mac's PCI bus thus starving your USB card.

    Are you running your Mac in dual processor mode? If so, that may be causing the problem.

    EDIT: Is your Mac's firmware up to date? If not, then check Apple's Web site for a newer version whose description may indicate that it was aimed at resolving a PCI bus issue. (It's a long shot...)

    --------

    Sorry for all these questions, but often troubleshooting amounts to eliminating the 99 things which aren't the cause in order to find the one which is.
     
  16. Aug 2, 2009 #16
    paulraphael

    paulraphael

    Apr 13, 2006
    Brooklyn
    If you heard me play, you'd stop reading what I write.
    I'll try a different PCI slot ... hadn't thought of that. If that doesn't work, I'm getting a powered USB adapter and crossing fingers.