H. J. L. Struycken was a Dutch otolaryngologist, phonetician, and acoustician. After studying medicine in Groningen, in 1893 he started working at the Voorburg psychiatric hospital near Vught, where he attempted to distinguish psychiatric conditions from neurological speech disorders. His interest in phonetics and acoustics took Struycken to France and Germany, to visit clinics and approach instrument makers who could produce tuning forks for him to use in his clinical research.

Jules Antoine Lissajous was a high-school teacher, then held prestigious administrative posts in the education system of various parts of France. He had trained in physics, and defended his dissertation on vibratory phenomena in 1850.

The silk manufacturer Johann Heinrich Scheibler invented a method to tune keyboards with unprecedented accuracy, applying principles that he had developed in his textile factory. His technique involved a set of tuning forks called a tonometer, a chronometer, and the counting of beats. It aimed to deskill tuning so that anyone could achieve precise tuning regardless of their musical ear. He explained his invention in Der physikalische und musikalische Tonmesser of 1834.

Karl Rudolph Koenig (also known as Rudolf Koenig or König) studied at the University of Königsberg. In about 1852, he moved to Paris and joined the workshop of famous violin-maker Jean Baptiste Vuillaume. In his leisure time, Koenig attended public lectures and studied mechanics, becoming increasingly interested in acoustics research. After six years of apprenticeship with Vuillaume, Koenig became a master violin-maker, but his own new business was a workshop for acoustic apparatus.