This is from a post by Jeff Dunn:

Waits’ voice was described by music critic Daniel Durchholz as “sounding like it was soaked in a vat of bourbon, left hanging in the smokehouse for a few months, and then taken outside and run over with a car.” I’ve described him as sounding like he swallowed an angry cat that is now clawing its way out of Waits’ throat. Tony Bennent he ain’t. But that’s what makes him so real. He records songs exactly the way he wants to. He makes instruments from things he finds in junkyards and records on old tape recorders that really should be in junkyards. On his latest album he sings a duet with Keith Richards. Waits’ voice is so raw he actually makes Keef sound good.

Oh, but he is real.

And here's a couple of videos just to show how true this is.