Hum in krk classic 5 studio monitors?

silentforce Member Posts: 8 Member

I just got these and hooked them up through a 4i4 interface connected via usb to the computer. At first they are completely silent until I start playing audio and then the static sound is constant, sounding like white noise and it continues even after stopping all audio playback. Does anyone know what this might be? I appreciate any input.


  • JesterMgee
    JesterMgee Member Posts: 2,132 Expert
    edited November 2022

    You left out almost all the useful info you could...

    • What is this 4i4 interface (brand or link)
    • How do you have it connected to the monitors (RCA, XLR, TRS)? Google these terms if you haven't a clue
    • What is the level of the monitors set at?

    By the sound of it your interface or cables are causing hiss, more likely the interface especially if you have a very cheap no name interface connected by RCA

  • silentforce
    silentforce Member Posts: 8 Member

    Oh my bad, it's the scarlett 4i4 by focusrite. Using hosa trs balanced cables to connect to the interface. no matter the level the monitors are set at, the static is always there at the same loudness no matter how high or low I set the gain on the interface.

  • Uwe303
    Uwe303 Moderator Posts: 2,317 mod


    if you turn the volume down on the krk´s and increase the volume on the interface? Have you tried another usb port, usb cable to the interface, maybe play a bit with the power cords. If you have a BT mouse or stuff like that try without it, even if it should be no problem with balanced cables.

  • silentforce
    silentforce Member Posts: 8 Member

    Yeah, have tried different things to no avail. Typically the noise isn't that loud so Ive just been kind of ignoring it, and cant hear it when music is up a bit. thanks for the replies though. I may be having another issue which I will post if I can't resolve it. Are cables really a big source of problems? never felt like I had problems with them before and they've always been taken care of.

  • JesterMgee
    JesterMgee Member Posts: 2,132 Expert

    Couple of things since trying to describe what "kind of hum" is impossible so you kind of need to try and determine what the source is such as interference, ground loop or noise floor.

    Since this hum is always there no matter your monitor or interface volume settings then this seems to suggest a ground interference issue through to your monitors, likely noise from your computer induced through to the monitors. Laptops can be notorious for this because the grounding via the power supply can sometimes be terrible or only via the neutral line

    A few tests to try and see when this hum stops:

    With the interface connected to the monitors, disconnect it from the USB of the PC. You would expect that sound to completely disappear since the interface is no longer powered.

    Make sure your monitors and computer are connected to the same power strip on the same outlet

    Try connect to a different USB port.

    If you are using a laptop disconnect the laptop power supply and see if that stops it

    Try a test by powering the interface from a USB power adapter just to see if the same hum is heard

    It's common to have this kind of problem when using unbalanced TS or RCA connections but less likely (not impossible) with proper TRS cables... IF both your interface + monitors are properly balanced devices. What brand are the monitors (link)? Could even be although they have a 6.5mm phono input they are not TRS and only TS connection.

    In my box of test gear I have a power board I removed the ground pin from. This is not a suggestion if you are not technically minded but what this does is removes the ground path which will often stop the hum (at risk of killing you if there is a fault, so not a permanent solution) but can be a useful tool to test where the ground issue could be.

    May not be a ground issue at all, could be a fault somewhere but if you keep doing tests and ruling things out it should eventually reveal the likely cause.

    Possibly if it is a ground issue for balanced connections you may consider a ground loop isolator such as this one:

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