In my opinion, the death/thrash metal band Possessed started harsh vocals with their 1984 EP Death Metal; simultaneously, Chuck Schuldiner of Death used harsh vocals on Death's 1984 EP Death By Metal, which is still a death/thrash EP imo and not fully a death metal one. The first official death metal album is Death's Scream Bloody Gore released May 25, 1987.
Death's demo Death By Metal.
Possessed's demo Death Metal
From their 1985 Seven Churches album
Provided to YouTube by Legacy RecordingsDeath Metal · PossessedSeven Churches℗ 1985 Columbia Records a division of Sony Music EntertainmentReleased on: 2015-...
www.youtube.com
As for how the vocalists maintain their vocals for extended periods of time without their throats hurting and them damaging their vocal chords, they first learn how to sing, along with singing, vocal and breathing techniques.
The death metal growl and black metal scream/rasp/shriek are NOT using vocal fry, that would possibly permanently damage your vocal chords. They are some sort of exhale and in some cases inhale breathing technique that I'm not sure how to do. I can ask an online metalhead friend.
The vocalists always drink a glass or bottle of lukewarm or room temp water before practicing or performing and always do vocal warmup and other exercises, and are seen with a water bottle on stage during live performances.
The death metal subgenre brutal death metal, especially its subgenre slam brutal death metal / slamming brutal death metal ("slam" for short), however, does not use death growls. Slamming brutal death metal instead uses some sort of gurgly ribbity vocal style that sounds like frogs ribbiting, or pigs squealing, or sounds like water or liquid gurgling when it boils. An example (and diversity is in metal) is the band Syphilectomy from Nagaland, India.
Brutal death metal is the only subgenre of death metal to use this gurgly vocal style. Otherwise, this vocal style is found in the grindcore subgenres goregrind and pornogrind.
Honestly it took me a long time to begin liking slamming brutal death metal, because I hate this vocal style. It sounds stupid, and doesn't sound demonic like the cookie monster vocal style does. Anyway, this gurgly vocal style was introduced into death metal by the technical death metal band Demilich, with their 1993 album Nespithe.
There is also the one man brutal death metal band Heinous Killings (j0e w0lf3) who on his only album in 2006, Hung With Barbwire, uses "Predator style" (from the Predator and Alien vs. Predator movies) vocals.
