A Before and After Recording of the Same Song, by Mzao Waters...
​Singing 'Glycerine'  (Bush)
with Director Kathleen Saffas' Comments Below

Director's Note:  What's the difference in Mzao's Before & After???

00:40 - 00:55    You'll notice in the Before his pitch is slightly flat ~  
                                       After he has learned how to sing on the overtone.
             01:40      In the Before his jaw tension makes it difficult to produce high notes: he's squeezing out
                             the high notes.
                                       After - he supports the high notes with his body, instead of "squeezing" them out by
                                       tightening his jaws.
             02:07      In the Before the vocal fry is harsh and driven through his false folds; 
                                       After, he has control of the closure to make vocal fry.
                             In the Before you will notice his diction is unclear because of the extreme tension in his jaw:
                                       After you clearly hear each and every word.

Wendy Porter