A pure tone is a vibration of air back and forth at a certain frequency.
And it sounds like this.
If you want to raise the pitch of that tone, you can speed up those vibrations.
[higher, shorter tone]
But because you've sped the vibrations up, that tone doesn't last as long.
Slow it down...
[lower, longer tone]
...and that tone will go on for longer.
Pitch correction, or auto-tune, is clever.
When it changes a note that someone's not quite sung correctly,
it changes the speed of the vibrations,
but it also adds or removes some vibrations so the duration stays the same.
Except that's not quite the full answer.
Because musical notes don't sound like this:
They sound like this.
- ♫ Hello ♫ - ♫ Hello! ♫
- ♫ Hello... ♫ - ♫ Hello~ ♫
Ladies, gentlemen, and all in between,
the Gregory Brothers.
♫ Oh yeah, some talent's still require~d ♫
[effects and auto-tune fade out]
- I know we're wandering off, but I thought that sounded pretty good.
- That certainly worked for me.
- That's good. - It's a powerful note.
- That hurt! That actually hurt.