How does a pipe organ produce sound?

A pipe organ produces sound through a sophisticated system that directs wind into tuned pipes, functioning as a grand synthesis of woodwind and brass instrument principles. The process involves several key components:12

• Wind Supply: A wind generator, such as a rotary blower or bellows, provides a constant supply of compressed air to a reservoir, which maintains steady pressure before the air enters the wind-chest.3
• Mechanism: When an organist presses a key on the console, a mechanical or electrical system opens a valve, or pallet, allowing wind to flow into the specific pipe associated with that note.34
• Sound Production:
  • Flue pipes: These function like a recorder or whistle. Wind enters the pipe's foot and is forced through a narrow slit called the flue, striking an upper lip to create an audible frequency that is amplified by the pipe's speaking length.5
  • Reed pipes: These utilize a vibrating brass tongue. Wind pressure forces the tongue against an opening (the shallot), and its rapid, periodic movement creates pulsations of air that are stabilized and colored by a resonator.6

The pitch is determined primarily by the length of the pipe, while the tonal quality is shaped by the pipe's scale, shape, and construction materials.356