Sonomètre of Loulié

The sonomètre is a tuning device that French musician Étienne Loulié invented c. 1694 to facilitate the tuning of stringed instruments. Sébastien de Brossard considered this device to be "one of the finest inventions" of the 17th century.

On July 4, 1699, Étienne Loulié had the honor of presenting two inventions before the Royal Academy of Sciences in Paris. The records of the Academy (Procès verbaux) for that day read:

"Monsieur Loulié showed the Company a new machine he has invented, which he calls the sonomètre, by means of which anyone who has never tuned a harpsichord, as long as he has a sufficiently good ear to tune one string in unison with another, and one octave in unison with another, will on the first attempt tune the harpsichord as quickly, more easily, and in less time than the best music master tuning it by the ordinary method."