Wolf.

The name given to two undesirable and unpleasant sound effects which may occur in musical performance, one having to do with temperament and tuning, the other with a structural peculiarity in an instrument that sometimes gives rise to intonation difficulties.

On keyboard instruments with tuning systems that do not provide a note intended for use as A, playing G instead, with E in the same chord, produces an unpleasant effect, supposed to resemble the howling of a wolf. In Pythagorean intonation the wolf 5th is smaller than pure by 23½ cents, a quantity known as the Pythagorean comma. But the wolf 5th in any regular mean-tone temperament (where the ‘good’ 5ths are tempered two or three times as much as in equal temperament) is considerably larger than pure (see Mean-tone, Table 1). The tuner who follows a scheme containing a wolf 5th might choose some other location for it than G–E. C–A was occasionally used in the 15th century and D–B in the 17th for mean-tone temperament; B–F was favoured, or rather disfavoured, by many 15th-century practitioners of Pythagorean intonation. On normal keyboard instruments, Just intonation is virtually bound to involve more than one wolf 5th, including one among the diatonic notes, for instance D–A or G–D.

Apart from the context of tuning systems, the term ‘wolf’ is used to refer to certain individual notes which, owing to the structure of an instrument, are too loud or too soft or difficult to play quite in tune, compared with other notes. This kind of wolf is due to an irregularity in the resonance of the instrument which either enhances or absorbs (damps) one particular note, or to a strong and sharply defined resonance frequency that happens to be slightly sharper or flatter than some note of the scale. The latter situation is often found at the major 6th or perhaps 7th above the open G-string of the cello, and is sometimes rectified by squeezing the body of the instrument with the knees or by attaching a ‘wolf mute’ to the G-string behind the bridge (see W. Güth: ‘The Wolf Note in the Cello’, The Strad, xc, 1979, pp.355–7, 434–5); in violins of poor craftsmanship a wolf is often found an octave above the open G-string. On the old French (and also English) bassoon, the a was characteristically weak and unstable because its hole was particularly small and high up on the butt joint. Another classic example occurred on the old valved french horn in F, where frequently either the b' or b' (notated f'' or f'') would be weaker than adjacent semitones, and a strong lip was needed to avoid ‘cracking’ the note. When a pipe organ is placed in a resonant building, some notes are liable to be emphasized by this resonance, and these are softened during regulation by slightly closing the foot-holes.

GUY OLDHAM, MARK LINDLEY