"Miles also had a pimp's voice, the voice Amiri Baraka once described as his "hipster foghorn bass." That raspy whisper resulted from Miles's supposedly screaming at a promoter too soon after throat surgery."
A side note:
"BILLY CRYSTAL relates that Louis Armstrong came to a seder at Crystal's childhood home. He was a guest of Crystal's uncle, the famous music producer MILT GABLE. Armstrong, of course, was noted for his very raspy voice. Crystal's grandmother came up to Armstrong and said, "Louis, have you ever tried just clearing your throat, just coughing it up?"