Hey all, I've been getting this noise out of my set top box, desktop and laptop audio outs into my mixer. I've also tried using usb soundcards out ($5 from ebay) and they don't eliminate the problem. I thought I had it figured the other day but then it came back.

So I'm really at a dead end, so I'm wondering if someone can quickly identify what this could be. Ground loop (although it's not really a hum) or otherwise? It's not ambient microphone noise however as I have unplugged the microphone and it remains.

I've also tried equing it out, but it's basically right in the middle and high bass, so it really cuts out from the audio if I play it through the mixer if I turn down the appropriate frequency groups. I've also tried entering the actual frequency numbers, but it was too much work for not enough return. So I just want to remove the sound.


  • 1
    Your link doesn't work.
    – BenV
    Jan 14, 2011 at 13:33
  • Woops, sorry. That was me.
    – muntoo
    Jan 15, 2011 at 23:09
  • 1
    Yeah! I've heard this before too when I had the output of a cheap Alesis mixer with built-in USB sound interface hooked into a DJ mixer, and then out to amp/speakers from there. I've long since replaced the whole setup, but never did figure out the source of this noise.
    – Brad
    Jan 16, 2011 at 6:46

1 Answer 1


It is a 1kHz pink noise as you can see here:

alt text

It's the typical sound due to RF interference from electronic equipment, so a laptop or PC, or other system with a CPU.

  • +1: I was finally able to listen to the sample and I agree. See also audio.stackexchange.com/questions/261/…
    – Kim Burgaard
    Jan 16, 2011 at 17:01
  • Ok thanks! I thought it would be something like this. I already have one external sound card however it looks like I will need to purchase 2 more (Another one for laptop and one for desktop). Any suggestions on something inexpensive that will get the job done (don't need optical out or anything)?
    – Sam
    Jan 17, 2011 at 11:03
  • 2
    Just an afterthought, is there any way I can equalize this sound out?
    – Sam
    Jan 17, 2011 at 11:10

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