Don't know about the first one you described. But the high pitched one I believe to be the carrier wave as well. Usually for me it starts out lower then increases in pitch as I'm being launched.
I've also heard it form from the sound of my fan before. The sound of the fan started changing and then started increasing in pitch. It was a strange phenomenon because it was the fan, as it changed, it wasn't two sounds it was the one.
I've also heard it form from the sound of my fan before. The sound of the fan started changing and then started increasing in pitch. It was a strange phenomenon because it was the fan, as it changed, it wasn't two sounds it was the one.