This is not really an issue, just something that I noticed now after almost 6 years running the same Yamaha mixer that I want to check if it's normal in other interfaces.

I daily drive a Yamaha AG03 and I have nothing to complain about this mixer, latency is great and has more than enough inputs and outputs for me to make and mix music. Today I noticed that if I open up Studio One (my DAW of choice, might happen in every DAW), arm a track for recording, and add any frequency analyzer (using Pro-Q 3 for that in the screenshots), I see some very low noise content at around 5khz up until Nyquist. About -80db without a mic connected, zero preamp gain, fader down, and -20db pad enabled. If I try to hear it at my usual mixing volume (monitors or headphones), I hear nothing. It's only really audible if I give it the max +24db boost Studio One allows me, but at this point that would never happen in the real world.

I'm not concerned about the "noise" because I simply can't hear it, and once I turn on my mic or any other type of device, ambient noise simply makes it irrelevant.

Some pics:




For me, that looks like self-noise from the interface. I can't say it never happened before because it took me 6 years to notice it.

Just to make it super clear, I'm not really looking for a fix since it doesn't affect negatively my recordings. All I want to know if that happens in other interfaces and if someone here knows for sure if it's self-noise or something else.