I watched that whole video, and never noticed the sound. Mind you, with an 85% loss in one ear, low frequency and consonant deafness in both ears, and a surgery rectified other ear with 10% loss, I'm not surprised. So, I went back to that video, and after cranking up the sound to an uncomfortable level, I could hear the sound, but wouldn't have noticed it without Tom putting a raw sample into today's video so I could identify it. Here's the kicker. For those that found this sound irritating, loud, and annoying, that sound EXACTLY matches one of the noise spectrums my tinitus produces, 24/7. Try to imagine a very quiet room. To people like me with tinitus and hearing loss, it is far from silent. Sound is actually a relief. As Tom says, protect your hearing.