My recording setup is suddenly having an issue with microphone hiss. This hiss is overpowering in every recording that I do, and it shows up even when I set the gain to zero and turn phantom power off at the audio interface.

When the phantom power is on, but the gain is set to zero, this hiss is accompanied by my mic audio being extremely hot—even the smallest of sounds causes the audio to peak.

When the phantom power is off, my mic does not pick up any audio that I make, but the hiss is still present and gets recorded by my DAW. The hiss does not produce a constant frequency. It fluctuates up and down like TV static.

I have tried directly monitoring the audio via the audio interface, and the hiss doesn't seem present unless I increase my output volume to near-max, and even then, the hiss is pretty quiet.

I have tried turning on padding and enabling the low-cut on my mic to see if these were causing the issue, but neither stopped the hiss or prevented the hot audio.

I have tried using both Reaper and Audacity. The hiss and hot audio occur in both.

I have tried unplugging my audio interface and plugging it back in. I have also tried to find more updated drivers for my audio interface, but none were available.

I'm using an AT-2020 for the microphone, a UMC22 for the audio-interface, and a simple XLR cable to connect the two. My structure is as follows:

AT-2020 -> XLR Cable -> UMC22 Audio Interface -> USB -> PC

Given that the hiss occurs even when the microphone has no phantom power and since it occurs in multiple DAWs, I think the audio interface might have been broken somehow. What do y'all think?

Here is an example of the audio hiss with no phantom power and gain at 0.

  • 2
    A pure guess might be that the input gain pot has seen better days. Is the hiss still there with the mic completely disconnected? Does the hiss level change or jump dramatically if you turn the input gain, tap it or jiggle it? [Try this with either the phantom off or mic unplugged, so you don't hear the mic itself, then with it on & compare if the mic level & hiss change correspondingly.]
    – Tetsujin
    Apr 21, 2019 at 10:52
  • I just realized that I totally forgot to check with the mic totally unplugged. Yes, the hiss is still there with the mic completely disconnected, the hiss gets worse if you turn up the gain knob whether the mic is connected or not and whether phantom power is on or not. Tapping the gain knob doesn't have any effect. You can see a sample here of me turning the gain knob up without the mic connected, then with it connected here..
    – Rvby1
    Apr 21, 2019 at 19:34
  • 2
    Then my next conclusion is your gain structure after USB is too high; loud hiss plus quiet mic signal going into the red == too much input gain.
    – Tetsujin
    Apr 21, 2019 at 19:36
  • @Tetsujin, I'm a bit of a noob here. Any ideas on how I'd fix that?
    – Rvby1
    Apr 21, 2019 at 19:39
  • I'm afraid you'll have to find it in the manual[s]; I have neither Reaper, Audacity nor a Windows PC, sorry.
    – Tetsujin
    Apr 22, 2019 at 6:20

2 Answers 2


The hiss sounds like some induction coming out of your PC (power supply, CPU, graphics card). I have heard this kind of noise a couple of times when using cheap USB sound cards. Maybe you can hear some changes moving your mouse or opening/closing windows on the PC.


It's possible either the microphone, the cable or the interface is broken. To find out which item is the culprit, try swapping components:

  • connect the mic to a different interface or a mixer
  • try a different mic on your interface
  • try another XLR cable.

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