Free reeds vibrate without shallot contact, tuned by a movable wire.
Evidence
Free reeds that do not make contact with a shallot, as found for example in a harmonica or harmonium, do not produce as high a proportion of high harmonics since the airflow is never completely shut off. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1203 (
#expands, via linked claim)
Categorization
Category: Causal Relationships
Related
- Free reeds produce fewer high harmonics because airflow never fully stops (similarity 0.96)
- Reed shutoff produces sharp acoustic pressure variations that drive the resonator (similarity 0.85)
- Air reed pitch is set entirely by resonator length and pipe openness. (similarity 0.83)
- In organ reed pipes the resonator does not control the reed’s frequency (similarity 0.83)
- Rapid airflow cutoffs generate harmonic-rich tones in reed instruments (similarity 0.83)
- Open reeds must vibrate below the air column’s playing frequency to be stable. (similarity 0.82)
- The air reed’s fundamental frequency is set solely by resonator length and end condition (similarity 0.82)
- Lips only begin oscillating as a reed once airflow passes a threshold (similarity 0.81)
- An air column driving the reed kills the sound by opening on rarefaction (similarity 0.81)
- Positive feedback drives the reed to slam shut (similarity 0.80)
- Hard reeds fix pitch, freeing resonators to shape only harmonics (similarity 0.80)
- Reeds must vibrate faster than the air column to reinforce resonance (similarity 0.80)
- Reed oscillation is a damped spring cycle renewed by airflow (similarity 0.80)
- Organ reeds self-oscillate through repeated contact-with-shallot cycling. (similarity 0.79)
- Reed pipes behave as stopped-end resonators, unlike open-ended flue pipes (similarity 0.79)
Broader Connections
- Free reeds produce fewer high harmonics because airflow never fully stops
#expands(0.82) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1203 - Free reeds produce fewer high harmonics than beating reeds
#expands(0.78)