There are many ways to produce vocal overtones. It depends by the structure of our vocal tract - tongue, cavities, ... - and our sensitiveness. We could explain our technique here.
If you are well acquainted in theory and / or practice in vocal technique, harmonics and overtones, I would greatly appreciate if you put in a little time to answer the questions in this link below. Best wishes
Dag Arvid Thelle
Overtone Singing Techniques
101 members
Description
Study on innovation climate in the area of vocal technique and overtones in voices.
by Dag Arvid Thelle
Feb 17, 2020
If you are well acquainted in theory and / or practice in vocal technique, harmonics and overtones, I would greatly appreciate if you put in a little time to answer the questions in this link below.
Best wishes
Dag Arvid Thelle
Survey on innovation climate in the area of vocal technique and overtones in voices.