Here's another YouTube pitch on pitch tracking.This time, Chris specializes in showing normal speech pitch tracking while describing some general information on the processing method.
After the first Passaggio demonstration appeared, I received more information on other "real-time" pitch tracking methods. I see a problem here in the definition of real-time pitch display. In my lexicon, real-time processing means being locked in time with the onset of a signal waveform, without delay. The Passaggio pitch processor satisfies this criterion. On the other hand, I see no way that spectral processing can do this because of its windowing lag. This lag is not necessarily bad for the pitch display but it is a demonstration of the inherent problem in spectral methods for separating sound sources.
According to Chris, there is some unnoticeable delay in Passaggio due to the need for "double buffering" to maintain compatibility with the Windows operating system. This delay is not inherent in the WIV-based processing method.