Broadly speaking, I tend to think of higher-pitched vocals in metal as being 'black' and lower pitched grunting being 'death'. This is painting with huge strokes, but it's pretty close to the mark most times (cue for someone to post a link to a band that disproves this, like I care).
actually, I'll do it myself... Archgoat, I would call them a black metal band, yet their vocals are low.
my head is starting to hurt over-analysing this :lol: