A resonant cavity can isolate a single frequency from complex sound.

Evidence

A Helmholtz resonator is a cavity-type resonator, so constructed that it will vibrate only at a particular frequency. It was developed by the German physicist Hermann Helmholtz in the nineteenth century to analyze the harmonic components of complex sounds. — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 920

Categorization

• DEFINE: Defines the Helmholtz resonator, a core analytical tool for soundscape work.
• corroborated: 2 independent passages support this claim — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 920
• XREF: connects to: Steady-state flat-line sound is rare in nature and emerges only with the Industrial Revolution — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 127; An open mouth amplifies faint sounds by serving as a resonant chamber — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 191; Wind harps invented independently in Asia produced distinct single tones — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 845 (+12 more)

Broader Connections

• The hearing system actively filters and modulates sound more than passively receiving it #corroborates (0.55) — George Michelsen Foy, Zero Decibels, 558