Hermann von Helmholtz

Hermann von Helmholtz (1821–1894) held professorships in physiology and physics at Königsberg, Bonn, Heidelberg, and finally Berlin, working across optics, thermodynamics, and electromagnetism alongside his acoustics research. His 1863 On the Sensations of Tone built the Helmholtz resonator to isolate and measure individual partials, connecting the physics of vibrating bodies to the physiology of the ear and to musical consonance and dissonance — a psychophysical method, relating measurable stimulus to perceived experience, that shaped acoustics and music theory for the following century. Harry Partch discovered a translation of the book in 1923 and credited it as the discovery that turned him away from twelve-tone equal temperament toward just intonation.