I heard a high pitched whine from a 22 bullet. It had a train whistle effect as it passed.
About the sound, subsonic rifles make a sound that I’d describe as
“POOoooo-ervvfffffffffffffffff” with the bullet’s sound just being the whistling, which sounds like a spent, spinning spent fireworks wheel or anything else that spins really fast through the air. I think there was a little bit of a rather low tone to it as well. Supersonic ones make a simple CACK! which is loud but not loud enough to hurt your ears if it’s twenty yards away. I used to paint targets and stay off to the side and behind a hill when the people were shooting.