A wolf tone, or simply a "wolf", is an undesirable phenomenon that occurs in some bowed-string instruments, most famously in the cello. It happens when the pitch of the played note is close to a particularly strong natural

resonant frequency Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillati ...

of the body of the

musical instrument A musical instrument is a device created or adapted to make musical sounds. In principle, any object that produces sound can be considered a musical instrument—it is through purpose that the object becomes a musical instrument. A person who pl ...

. A wolf tone is hard for the player to control: instead of a solid tone it tends to produce a thin “surface” sound, sometimes jumping to the octave of the intended note. In extreme cases, a “stuttering” or “warbling” sound is produced, as in the sound example. This sound may be likened to the

howling Howling is a vocal form of animal communication seen in most canines, particularly wolves, coyotes, foxes, and dogs, as well as cats and some species of monkeys. Howls are generally lengthy sustained sounds, loud and audible over long distances, ...

of a

wolf The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly u ...

. A somewhat similar sound is the beating produced by a

wolf interval In music theory, the wolf fifth (sometimes also called Procrustean fifth, or imperfect fifth) Paul, Oscar (1885). A manual of harmony for use in music-schools and seminaries and for self-instruction', p.165. Theodore Baker, trans. G. Schirmer ...

, which is usually the interval between E and G of the various non-circulating temperaments.

Stringed instruments

The physics behind the warbling wolf was first explained by C. V. Raman. He used simultaneous measurements of the vibrating string and the vibrating body of the cello, to show that the warbling sound is caused by an alternation of two different types of string vibration. All bowed string vibration is “stick-slip oscillation”. One of the vibration types involves a single slip in every cycle of the note, but the other type involves two slips per cycle. Frequently, the wolf is present on or in between the pitches E and F on the

cello The cello ( ; plural ''celli'' or ''cellos'') or violoncello ( ; ) is a bowed (sometimes plucked and occasionally hit) string instrument of the violin family. Its four strings are usually tuned in perfect fifths: from low to high, C2, G2, ...

, and around G on the

double bass The double bass (), also known simply as the bass () (or by other names), is the largest and lowest-pitched bowed (or plucked) string instrument in the modern symphony orchestra (excluding unorthodox additions such as the octobass). Similar ...

. A wolf can be reduced or eliminated with a piece of equipment called a wolf tone eliminator. There are several types. The one illustrated is a metal tube and mounting screw with an interior rubber sleeve, that fits around one of the lengths of string below the bridge. The position of the tube must be adjusted so that the short section of string resonates exactly at the frequency at which the wolf occurs. It works in the same way as a tuned-mass damper, often used to reduce vibration of bridges or tall buildings. An older device on cellos was a fifth string that could be tuned to the wolf frequency; fingering an octave above or below also attenuates the effect somewhat, as does the trick of squeezing with the knees. While it has been said that

Lou Harrison Lou Silver Harrison (May 14, 1917 – February 2, 2003) was an American composer, music critic, music theorist, painter, and creator of unique musical instruments. Harrison initially wrote in a dissonant, ultramodernist style similar to his fo ...

wrote a piece (evidently reworked as the second movement of the ''Suite for Cello and Harp'') that exploited the wolf specific to

Seymour Barab Seymour Barab (January 9, 1921 – June 28, 2014) was an American composer of opera, songs and instrumental and chamber music, as well as a cellist, organist and pianist. He was best known for his fairy tale operas for young audiences, such as '' ...

's new cello, there is no clear evidence that this occurred. "Naldjorlak I", composed by

Éliane Radigue Éliane Radigue (born January 24, 1932) is a French electronic music composer. She began working in the 1950s and her first compositions were presented in the late 1960s. Until 2000 her work was almost exclusively created with the ARP 2500 modul ...

for realisation exclusively by the cellist

Charles Curtis Charles Curtis (January 25, 1860 – February 8, 1936) was an American attorney and Republican politician from Kansas who served as the 31st vice president of the United States from 1929 to 1933 under Herbert Hoover. He had served as the Senat ...

, is in fact composed solely around the manipulation of the wolf tone of Curtis's cello.

References

{{Reflist *Wilkins, R.A.; Pan, J.; Sun, H. (Fall 2013). "An Empirical Investigation into the Mechanism of Cello Wolf-Tone Beats". ''Journal of the Violin Society of America''. 24 (2). *Wilkins, R.A.; Pan, J.; Sun, H. (Fall 2013). "An Investigation into the Techniques for Controlling Cello Wolf-Tones". ''Journal of the Violin Society of America''. 24 (2). Sounds by type Resonance String performance techniques

Stringed instruments

See also

References