This is a continuation of my previous question about ear fatigue. I continue it here with a better audio example and more clarity on the culprit.
Basically...my recordings give me ear fatigue, like there is a lot of pressure in the audio when listening. I suspect due to artifacts throughout the EQ spectrum, mostly quieter than the recording so they're not obvious, but they fatigue the ears quickly as they are there.
See link for audio sample of a prominent ghost artifact: https://ufile.io/nfva07zq (Dec 29) It sounds like a whistle in a cave. It's more audible in the attached snippet but occurs throughout the recording if you listen very carefully. Frequency sweeps identify many seemingly arbitrary areas throughout the spectrum to be subject to this.
Where is this coming from? Am I right that maybe the Surface Pro's sound card is picking up interference from the power supply or battery or some other component? What would be a solution or better set up? I record a Yamaha amp directly into USB on MS Surface Pro laptop. The USB port is near the power input. Unplugging the power doesn't improve. When monitoring the amp during play, I don't get any audio interference. Playback on laptop or phone is the same.