I was pretty amazed how consistently the sigmund~ external for pure data worked with singing/piano/individual notes. Its truly amazing!
[http://www.maxobjects.com/?v=objects&id_objet=4713](http://www.maxobjects.com/?v=objects&id_objet=4713http://)
Apparently it works with max too - never tried it.
Isn't there a vst wrapper for pure data - maybe it works inside Isadora!
I never tried [this](https://puredata.info/downloads/aubio) but maybe its also interesting.