What defines a bad vocalist for you? My belief has always been that "one man's shit is another man's butter" but5 there are some who are just REALLY bad.
Let's list them and try and work out what a bad voice is so that we can learn to avoid it.
I hate that tuneless, slightly flat and nasal delivery that populates dad rock bands like The Vaccines, Doves and Embrace. All sounds the same to these ears - pure shite.