Free aerophones [41]

• Displacement free aerophones [411]
  (swordblade, whip)
• Interruptive free aerophones [412]
  1. Idiophonic = reeds [412.1]
     1. Concussion reeds [412.11]
     2. Percussion reeds [412.12]
     3. Free reeds [412.13]
     4. Band reeds [412.14]
        1. Playing the blade of grass
        2. Make a vroomator
        3. Make a humming stick
  2. Non-idiophonic [412.2]
     1. Rotating aerophones (siren) [412.21]
     2. Whirling aerophones [412.22]
        1. Make a bullroarer
        2. Make whirligigs
• Plosive free aerophones [413]
  1. Explosive aerophones [413.1]
     Make pop guns
  2. Implosive aerophones [413.2]
     Make a set of end-struck pipes