Do singers like Waits achieve a "gruff" vocal sound by some sort of technique, or is it just from smoking a lot?
Tom had this to say in an interview:
"I bark my voice out through a closed throat, pretty much"
The smoking didn't hurt, but it's a vocal technique. Check out Captain Beefheart and Howling Wolf. They were both influences to his vocal style.Captain Beefheart Howlin' Wolf
It could be HPV (human papilloma virus) which can in a small percentage of men attack the vocal chords. Instead of vocal cords that resemble violin strings, HPV turns them into jello, making clear crisp sounds difficult.