Janis Ian:

Like me, my favorite singers had one thing in common -- none of them were born with beautiful voices.  They'd had to make themselves great singers.  In fact, I've often wondered whether that's why most people who are born with beautiful voices are not, by and large, extraordinary singers.  They may become great vocalists, for sure.  They may sound pretty,  But the grit, the steel, the nuances that make for great interpretation...well, they're usually not found in pretty voices.  They're found in people like Billie Holiday, Edith Piaf, Ella Fitzgerald.

Society's Child, p. 170