Blocking violin f-holes destroys the Helmholtz resonance and alters tone

Evidence

It is quite interesting to make other nondestructive modifications to a violin. The effects can easily be heard and measured. Plugging up the f-holes ruins the Helmholtz resonance and the ported loudspeaker effect, leaving the violin sounding more nasal and less robust, as does putting helium inside. (It quickly escapes, so the violin has to be played upside-down to keep the gas trapped!) — Eric J. Heller, Why You Hear What You Hear- An…, 1810

Categorization

• CANDY: Playing a violin upside-down to trap helium inside is a delightfully absurd image perfect for casual conversation.
• XREF: Connects to Helmholtz resonator theory — ties the violin’s body to resonator physics used across acoustics.