lowThose notes are too low for me.
low-pitchedThe low-pitched rumble of the train shook the house.
throatyShe gave a loud, throaty laugh.
huskyShe's got a husky voice and is always cast as the romantic lead because of it.
gravellyThe actor is famous for his rough good looks and gravelly voice.
gruffHis loud, gruff voice frightened the neighbourhood children.
sonorousHis sonorous voice rang through the halls.
bassThe bass part is quite difficult to sing.