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Recently I noticed a high pitched noise in my recording setup in my new house, 5.5 kHz to be precise as you can see in the image below of me playing a bass note. This noise only is present when actually playing a sound. You can see the noise stopped when I muted the string.

Bass note and 5.5 kHz noise

I've tried to figure out what is causing this noise. The noise is present on both the XLR and the jack input on my Roland Tri-Capture, it does not matter which instrument I am recording (electric drums, bass guitar, electric guitar, acoustic guitar, vocals). I have tried unplugging all other electronic equipment from the power strip of the PC (except the PC and the monitor) and change to a different power strip and a different outlet but that didn't change anything.

Somewhere someone had a noise that changed pitch when he changed the sample rate between 48 kHz and 44.1 kHz, my noise stays the same regardless of the sample rate.

What are other steps I can take to find the source of this noise? Or any ideas how to get rid of the noise (aside from EQ'ing it)?

Find the WAV of the sample here.

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This is a broad sweep at the issue, some guesswork & experimentation required.

First of all, if you have an alternative DAC try it, no matter how basic, just to eliminate the simplest explanation.

Secondly - if anything has batteries, replace them.

Up at 5k, it's unlikely to be directly related to 'mains hum' itself, grounding issue etc.
A very simple test for 'mains hum' is hold the strings, let go the strings, see if the sound changes. It's worth a go, but I don't think this is going to be the root cause. It may be acting as a radio, though, picking up leakage from somewhere nearby, so the second test would be to rotate yourself & guitar & see if pointing in a certain direction changes anything.

I think the main possibility is going to be a switch-mode power supply. These would be anything with a 'wall wart' or such as computer screens, lighting circuits & laptops. These things can be producing RF at anything from a few KHz to well outside audible range.

Screen & lights are the simplest to test for, because the computer will still work without the screen on - record something with the screen unplugged from the wall & all lights off.

After that it gets harder, because not all switch-mode PSUs are simple 'wall warts'. There may also be one on a desktop computer's PSU or one in even an ostensibly mains-powered screen.
If it's a laptop, simple - record on battery power & see if it goes away.

For a desktop, if you got this far with no discernible change, then I'd be looking at its power supply - but there I have no method for testing; I'm not an electronics guy.

If you do find the source & it's not easily replaceable, then your options come down to distancing it from anything that can pick it up, or something like a Faraday cage.

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  • Thanks for the Tetsujin! I have plugged the DAC into a laptop that I unplugged from the wall. The noise was still present. So since the noise happens on both my desktop and unplugged laptop it is verly unlikely to be related to anything about power correct? I found out the noise also happens when playing audio from my phone via RCA into the Tri-Capture (though only noticeable when playing Bad Guy with mostly low sounds :-P). When I plugged the phone into the mic input on my desktop and send that output to my headphones the noise was no longer present. So it likely is related to my DCA? – Bob Mar 28 at 12:01
  • Yeah, it's sounding like the Roland is to blame. Take it up with them, see if they've got an answer. – Tetsujin Mar 28 at 12:07
  • Well, I bought it around 7 years ago and it has been discontinued a couple years ago I believe. And I was actually looking to replace it with something newer anyway. Anyway thanks for the help! I was getting worried that I might not get rid of the noise but it seems like it's going to be fine :-) – Bob Mar 28 at 12:14
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5.5kHz is suspiciously close to a fraction of 44100Hz, a typical sampling frequency. This could be a resampling artifact if your audio interface is working with 44.1kHz and your DAW with 48kHz or vice versa.

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  • That is an interesting thought, I have tried both 44.1kHz and 48kHz and the noise stayed the same. Based on what Tetsujin suggested I think the DAC has become faulty, but maybe it is related to this frequency. It is suspiciously close, also to a fraction of 48 kHz. – Bob Mar 31 at 9:53

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