Changing membrane tension during ringing produces a controlled pitch glide

Evidence

During a performance, its tuning can be changed in semitone steps by means of a lever tensioning system operated by a pedal, which typically enables a pitch variation over five semitones. The head tension varies as the lever is moved from note to note, and, if the kettledrum is struck immediately prior to the lever being moved, a rising (or falling) pitch is heard as a glide or glissando. This is sometimes used for musical effect. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1324

Categorization

• FICTION: Reads as a ready-made sonic device for a story — an instrument capable of bending pitch mid-note becomes a plotting tool or a metaphor for indecision/transition.
• CANDY: A neat, quotable fact: striking a timpano while moving the pedal makes the note glide like a slide-whistle effect used deliberately.
• XREF: connects to: A struck membrane’s perceived pitch depends on suppressing inharmonic modes — Eric J. Heller, Why You Hear What You Hear- An…, 1411; Vocal pitch is controlled through fold tension and vibrating mass; Pitch is controlled by string length, tension, or mass

Broader Connections

• A struck membrane’s perceived pitch depends on suppressing inharmonic modes #expands (0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 1411
• Vocal pitch is controlled through fold tension and vibrating mass #expands (0.75)
• Pitch is controlled by string length, tension, or mass #expands (0.70)