How do wind instruments produce sound?

Wind instruments, classified as aerophones, produce sound by setting an enclosed column of air into vibration. This process is initiated by the performer's breath or a mechanical bellows acting upon a sound-generating device.123

The specific mechanism of sound production varies by instrument type:

• Brass instruments: The player’s lips vibrate against a cup- or funnel-shaped mouthpiece, creating air pressure eddies that set the air column inside the tube into motion.12
• Woodwinds: These instruments use either high-pressure air eddies—created by blowing directly into or across the instrument—or a vibrating reed to initiate the air column's movement.1
• Pipe organs: These produce sound through tuned air columns in pipes, either via flue pipes or by using forced air to actuate a vibrating brass reed.1

Once the air column is vibrating, it forms a standing wave with nodes and antinodes. The length of the tube determines the fundamental pitch, which can be altered by using valves, slides, or keys to change the effective length of the air column. Through overblowing, players can access the harmonic series to produce a range of higher pitches.312