Here are some tutorial videos that explain the usage of Overtone Analyzer and VoceVista Video.
Introduction to recording and visualizing sound, and most other general features of the software.
Please note: This tutorial was made for Version 4.0 of the software. To follow it with the current version, please use VoceVista Video.
Using VoceVista Video, singer Anna-Maria Hefele explains various techniques of overtone singing. This video shows many features of the software, so while it is primarily about overtone singing, it is also a good introduction to spectrograms, and to Overtone Analyzer and VoceVista Video.