Shirley Verrett’s voice is repeatedly referred to as Superhuman.
Shirley Verrett was an internationally renowned opera singer and concert recitalist. Her performances and recordings marked her as one the leading singers in the post-Marian Anderson generation of African American classical musicians.
Shirleyverrett.com
Her entire discography is listed on her posthumous website.
(… and to nudge you down the rabbit hole created by the supersonic voice her spirit housed here’s a second recording of her just practicing Rossini:
https://youtu.be/GRP-tx-kpec )