here is a short demo of a vocal pitch tracker, done entirely in puredata and compiled to c-code with heavy. the whole thing runs on BELA (a great platform for low latency audio). i was astonished at the tracking i got!!

https://soundcloud.com/simon-iten-294936446/voxtosynthbela p.s. i am not much of a singer, this is just for demo purposes (synth on one, dry vocals on the other channel)