That's interesting chrisg, because I have been wondering how to make that answer fit with the "vocal" in the clue.
When I was trying to solve it myself initially, I took that as a reference to the sound and was looking some sort of pun.
But on the other hand, in favour of that answer, a char or charwoman or charlady "does" - so it fits the first part of the clue, the wording of which ("Do..." )otherwise seems odd.