Quickly and clearly pitch-shifting vocals on mac

Hi,
I'm seeking an accessible app that will let me pitch-shift some vocals, without altering speed, and also retaining the clarity of the original vocals. Amadeus pro has a pitch shifter, but it muddies the audio, even when the quality is set to best. Is there an app to let me lower the pitch of vocals, while retaining quality? Reaper probably would, but I'm so impatient, and reaper right now is a bit over my head, lol.