"She can turn anything into gold with that voice, here's the thing: if you speak to a good singing teacher about great opera singers, they will talk about consistency of tone. Or there's a book by Alfred Tomatis about why some people like certain people's voices and other people hate them, like Bob Dylan or me or whoever, some people say, 'Oh, I hate that voice', so there's a thing about people's frequency responses, what they are pleased by. Rihanna has this thick tone, so it's very hard to annoy anybody."