v.1. To write something very quickly, especially using a keyboard: Facing a deadline, the writer banged out an editorial for the paper. I need to reply to the bank right away; could you bang a letter out for me?
2. To play a piece of music very loudly, especially on a piano: I sat down and banged out some funny songs to entertain my friends. I think of this waltz as a quiet piece of music, but some players really bang it out.