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Resonantia · Plate № CXIV
f← Index
Acta Phonica · Liber I
02·V·MMXXVI
Plate № CXIV — figurae sonorae

ResonanceLaboratorium

Ernst Chladni dusted square plates with fine sand, drew a violin bow across the edge, and made standing waves visible. Grains fled the antinodes and settled on the silent nodal lines — geometry from sound itself.

i. modal indexm × n
∙ m
∙ n
ii. cataloguecum nomine
vibratingfigura (3, 5)641 hz
eigenfrequency641Hzf ∝ √(m² + n²)
sand grains8.0kquartz · 1px walk
iii. apparatusiii.
vibration0.018
quartz8000
persistence0.18

method

Each grain executes a random walk whose step length scales with the local amplitude of the standing wave. Where the wave vanishes — the nodal lines — the grain settles and the figure emerges.

χ(x,y) = cos nπx · cos mπy − cos mπx · cos nπy

marginalia

Pairs (m,n) and (n,m) yield congruent figures rotated by a quarter turn. Equal indices m = n produce diagonal lattices; coprime indices produce lace-like asymmetry. Try (3, 7) at low vibration for the canonical Chladni rose.

colophon

Set in Cormorant Garamond & JetBrains Mono. After Chladni's Entdeckungen über die Theorie des Klanges, Leipzig 1787. Pressed in the Fezcodex laboratory, anno MMXXVI.

— f.