I show my way to work with formants and overtones.
Before I need to explain the A B C of formantic theory and classic theory of harmonics because can be somebody that doesn't know them, but I wouldn't seem a teacher.
Sorry for my bad English.
Some simple acoustic notes: to measure a sound timbre we need many parameters, it can't be maked by frequencies and intensity only.
Helmholtz advanced this theory:
each natural sound is composed by a group of different frequencies, called harmonic components, everyone with different intensity. These harmonics create our timbre perception.
So each sound wave can be divided in many sine (or cosine) waves, each one with its frequency, its intensity and its phase.
(to be continued)