Assertion: oboe's reed | /r/CapableOf | seal the mouthpiece opening
Facets:
value: for part of the wave cycle
type: TEMPORAL
Source sentences:
text: Harmonics are caused by factors including the imperfect wobbling and shaking of the reed, the reed sealing the mouthpiece opening for part of the wave cycle (which creates a flattened section of the sound wave), and imperfections (bumps and holes) in the bore.