Changing key of project without changing pitch Garageband v10.1.0
I started recording a project in Garageband v10.1.0 without putting much thought in labeling the key of the recording. Now that I'm well into the process I want to change the key to reflect the correct tonality (E major), but when I try to switch from C to E in the key slider, the pitch is shifted as well. How can I change the "key of the project" without affecting the pitch of the audio files?
MacBook Pro (Retina, 15-inch, Mid 2014), OS X Yosemite (10.10.4)