Spectrogram Frequency Analysis
The noise that sounds a bit like a saw consists of a permanent “carrier signal” between 1.93 and 1.97KHz and an oscillating buzz that’s located a bit lower on the spectrum. It’s really annoying. Let’s take another look at the frequency analysis that was recorded with a high-quality measurement microphone from a distance of 30cm.
The deeper parts aren’t as pronounced as the whistling noise, but can still be easily made out on the spectrogram. The higher frequencies far exceed 20KHz.