Soundboards are designed to minimize short-circuiting by lowering critical frequency

Evidence

Webster’s Dictionary defines a sounding board in a seemingly uncontro-versial way as a “resonator consisting of a thin board whose vibrations reinforce the sound of the instrument.” In what sense is a piano soundboard a “resonator”? Are the piano’s tonal qualities dependent on the positions of the resonances?

A piano soundboard is made of strips of spruce, reinforced with additional rib cross-bracing. The idea is to make it as light and stiff as possible, which speeds up bending waves. The critical frequency will then be lowered, and above that frequency short-circuiting will be minimal.

— Eric J. Heller, Why You Hear What You Hear- An…, 1166

Categorization

• DEFINE: Introduces the critical frequency concept and what short-circuiting means for soundboards.
• SEED: The tension between dictionary definitions of ‘resonator’ and how real instruments actually work could anchor an article on how technical definitions fail to capture designed function.