"Another Video" Male

This is on ND, recorded on May 19, 2023. "Another video." Male What's strange about this audio clip is the frequency modulation that occurs at the "tone" that is being played at 208 hz. On a spectrogram, a solid, pure tone, is seemingly being played at 208 hz that has no audible sound but has the highest dB in the clip. When the tone ends, spiral shapes come off of it which is consistent with the process of frequency modulation.