Death metal, in particular, is associated with growled vocals; it tends to be lyrically and thematically darker and more morbid than other forms of metal, and features vocals which attempt to evoke chaos, death, and misery by being "usually very deep, guttural, and unintelligible".
Death metal, specifically, is associated with harsh vocals; it tends to delve into darker, more ominous subject matter in its lyrics and themes, and features vocal styles that seek to evoke feelings of anguish, devastation, and hopelessness through their low, guttural, and often incomprehensible sound.