Musical instruments based on air columns are generally excited by resonance. The
air column is presented with a sound wave that is rich in many frequencies. The air col-
umn then responds with a large-amplitude oscillation to the frequencies that match
the quantized frequencies in its set of harmonics. In many woodwind instruments, the
initial rich sound is provided by a vibrating reed. In the brasses, this excitation is pro-
vided by the sound coming from the vibration of the player’s lips. In a flute, the initial
excitation comes from blowing over an edge at the mouthpiece of the instrument. This
is similar to blowing across the opening of a bottle with a narrow neck. The sound of
the air rushing across the edge has many frequencies, including one that sets the air
cavity in the bottle into resonance.