Organ reeds self-oscillate through repeated contact-with-shallot cycling.
Evidence
The reed is springy and once the gap is closed and the flow has dropped to zero, the reed’s restoring force causes the reed to spring back towards its equilibrium position, opening the gap. The reed overshoots its equilibrium position, stops, and returns towards the shallot, in a manner similar to its vibration if it had been displaced from its equilibrium position and released by hand. Airflow is restored via the shallot and the cycle repeats. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1228
Categorization
Category: Causal Relationships
- XREF: Connects to relaxation-oscillation mechanics found in other periodic systems — a nice bridge between acoustics and general oscillation theory.
Related
- Reed oscillation is a damped spring cycle renewed by airflow (similarity 0.89)
- Reed oscillation is self-sustaining through a positive feedback loop of airflow and pressure (similarity 0.88)
- Positive feedback drives the reed to slam shut (similarity 0.87)
- Lips only begin oscillating as a reed once airflow passes a threshold (similarity 0.84)
- Pressure feedback drives the reed into full closure across each cycle (similarity 0.83)
- Reed shutoff produces sharp acoustic pressure variations that drive the resonator (similarity 0.81)
- Free reeds vibrate without shallot contact, tuned by a movable wire. (similarity 0.79)
- In organ reed pipes the resonator does not control the reed’s frequency (similarity 0.79)
- Reflected pulses at the flue end flip the air reed’s oscillation direction (similarity 0.78)