Organ pipe

An organ pipe is a resonator that produces sound when pressurized air flows through it. Its pitch and tone depend on its dimensions, shape, and method of excitation.

Flue pipe: An organ pipe that produces sound by directing an air jet across an opening, causing the air column to resonate. Its windway and labium turn the organ’s airflow into a vibrating air column.
Open pipe: A resonating pipe open at both ends, with pressure nodes at its ends. Many organ pipes are open at both ends and support a full harmonic series.
Principal (organ stop): An organ stop with pipes that form the instrument’s characteristic foundational tone. Principal pipes provide the core sound around which many registrations are built.
Hydraulis: An ancient Greek pipe organ that used water pressure to regulate its air supply. It is an early documented ancestor of instruments built around sounding pipes.
Reed pipe: An organ pipe in which a vibrating reed sets the enclosed air column into motion. Its reed, rather than a free air jet, supplies the initial vibration.
Stopped pipe: A resonating pipe closed at one end, with a pressure antinode at the closed end. Stopping one end lowers the fundamental pitch for a given pipe length.
Flute (organ stop): An organ stop whose pipes produce a flute-like tone, usually with relatively weak upper harmonics. Flute pipes show how pipe construction creates a rounded, soft register.
Ctesibius of Alexandria: A Greek engineer of the third century BCE associated with inventions including the hydraulis. The hydraulis linked his engineering work to early organ pipes.
Helmholtz resonance: Resonance produced by air moving through an opening into a cavity, as in a bottle. It helps explain why a pipe’s openings and enclosed air affect its resonant behavior.
Harmonic series: A sequence of frequencies at integer multiples of a fundamental frequency. The harmonic structure shapes the timbre of many organ pipes.

Linked from 8 pages