Pitch and tempo change in Garage Band or Logic
I want to make a song go faster with the pitch also changing so the vocals become chipmunky. Either Garage Band or Logic Pro.
iPad Pro, iOS 12
GarageBand and Logic are trying to keep the voices sound natural, when you increase the tempo. I would use the Vocal Transformer plug-in to turn the vocals into the Chipmunk voice.
In the Vocal Transformer you can raise the pitch by two octaves and increase the setting for the formant too: For example:
In my GarageBand version is a readymade vocal patch called " Experimental > Helium Voice", that is coming close to a Chipmunk voice.