### Clue: Famous trumpet piece? Not impressed (9)
### Answer: VOLUNTARY 
 ### Explanation: Definition: Famous trumpet piece,Not impressed
  Double defn: 1st: An English keyboard piece from the Baroque era, usually played on the organ using the trumpet stop – the most famous is perhaps Jeremiah Clarke's Trumpet Voluntary, mistakenly attributed to Henry Purcell; and 2nd: The opposite of,not being impressed/pressed/forced into, say, maritime service.  Another nautical reference.