Object, Instrument, Technology

See also Tuning fork

Picture: Max Planck Institute for the History of Science

Image
“Tuning Fork Collection Ii, Detail 1”. n.d. Berlin.
Object, Instrument, Technology

Wooden sticks, when dropped on the floor, sound a variety of tones. While the bars of a xylophone are varied in tone by changing their length, these “tone bars” are all of the same length and width, but have different thicknesses and different densities and elastic properties.

Object, Instrument, Technology

A tonometer consists of a series of steel cylinders that resonate at specific frequencies upon being struck with a metal hammer. They are used as standards for high frequencies, in the same manner as tuning forks. The transverse vibrational frequencies (i.e. fundamental and harmonics) of a given cylinder depend on the length, elastic modulus, and linear density of the metal.

Object, Instrument, Technology

William Stern invented the tone variator in 1897 to study human sensitivity to changes in pitch, going beyond the traditional psychological research of studying the sensitivity to differences in discrete tones. The instrument consists of an adjustable brass resonator (see Helmholtz resonator for more information), which is supplied with a constant flow of air across an opening at the top.

Image
“Tuning Fork Collection Ii, Detail 6”. n.d. Berlin.
Object, Instrument, Technology

See also Tuning fork

Picture: Max Planck Institute for the History of Science

Object, Instrument, Technology

Invented by John Shore in 1711, the tuning fork was initially used by musicians. After Chladni’s studies of its vibrations, however, it was also extensively employed by acousticians, who praised the purity of its sound. Hermann von Helmholtz, especially, based his experiments with beats, combination tones, and simple tones on tuning forks attached to resonators that enhanced their suitability for experimentation.

Object, Instrument, Technology

The sound synthesiser was Helmholtz’s clearest instrumental expression of his theory of timbre, or sound quality. Whereas his spherical resonators dissected compound sounds (vowels or musical sounds) into elemental frequencies, the synthesiser did this by building up complex sounds from simple frequencies. In 1857 he went to the instrument maker Friedrich Fessel of Cologne to turn this idea into reality. The initial instruments used a combination of electrically driven tuning forks, resonators and piano keys to synthesise compound sounds.

Object, Instrument, Technology

The forks give the notes ciii, civ, div, eiv, fiv, the 11th harmonic of c1, the 13th harmonic of c1, aiv, the 14th harmonic of c1, bv, and cv (ciii and cv have vibration frequencies of 1024 and 4096 respectively).

These forks are constructed to prove the following law: