Possible Clues:

• It takes a tin gun to be getting the notes right (6)
• Preshow ritual
• - Fork aids a musician
• Getting the pitch in good order
• Piano work
• Going off right away - doing this to find a station
• Calibrating
• The way to get the key right, by the sound of it
• This fork is used to adjust piano notes
• Adjusting (eg, a piano)