Help! Can't pinpoint this sound

Hi all,

I was hoping someone on this board can help me. About half about me recordings have this high frequency, wave kind of sound in the background that I can’t pinpoint to eliminate. The sound, (attached) isn’t audible while recording, only on playback. Preferably, I’d like to eliminate the source and not in post. Any help would be super appreciated, it’s driving me nuts!!!

It may be some sort of electrical interference. What equipment are you using?

Nothing terribly complicated, a pair of AT2020 mics, a small 12V Fifield headphone amp through a Behringer QX1202 USB mixer. My initial thought it was electrical as it was plugged into an outlet on a shared wall (apartment living), unfortunately, moving the the power to other outlet gave the same sound.

Try making another test recording (just like your audio sample), but this time, half way through the recording, turn down the “gain” on the mixer for both mics (all the way down). We would expect the “hiss” noise level in the recording to go down half way through the recording. Does the high pitched warbling sound also go down or is that still there?

I was thiiiiis close to throwing in the towel. That could be slow speed data transmission.

Can you try a recording from somewhere else, like a couple of blocks, 1/4 mile away?

Are you close to an airport or other building with towers or antennae?

Can you make a recording without plugging into the wall at all? What’s the computer? Laptop?

You can’t hear it when you listen to the computer during the recording? I know the timing and theater is going to be destroyed by doing that, but it would be valuable to know that the sound is clean on the mixer headphones, but it’s there on Audacity Playthrough during the recording.

How close is the mixer or any of the audio cables to the mixer power supply brick? Does it change if you separate them? That is not a simple DC adapter. That thing is doing some serious power supply heavy lifting.