It's not going to directly teach you how to build a harmonizer, but this guy has a series of incredible videos on audio processing that might be helpful: https:

It's not going to directly teach you how to build a harmonizer, but this guy has a series of incredible videos on audio processing that might be helpful: https://www.youtube.com/playlist?list=PL-wATfeyAMNoirN4idjev6aRu8ISZYVWm https://www.youtube.com/playlist?list=PL-wATfeyAMNoirN4idjev...