Here's a very basic patch I made that automatically "double-tracks" the input. It uses a vd~ in order to add some subtle pitch and timing differences, similar to the way ADT was originally used by the Beatles.

The left outputs the altered signal, while the right is the dry signal. Most useful for a live-vocals setup.
ADT~.pd

@pooopsi
Not sure if you're still working on this, but here's a simple pitchshifter I've been using. cpitchshift.pd