(Fr. barre; Ger. Bassbalken; It. catena).
In bowed string instruments, a strip of wood glued to the underside of the belly beneath the bass foot of the bridge. It is of vital importance to the acoustical function of the instrument, and is complemented by the soundpost which is placed close to the treble bridge-foot. In modern practice, the bass-bar runs for three-quarters of the length of the belly, and is made from spruce carefully matched to that of the belly. It is fitted slightly within the outer edge of the bridge foot, and set at a slight angle to the centre line of the instrument, determined by the proportions of the upper and lower bouts. It is deepest at the centre, generally about 12 mm in a violin, and tapers towards the ends, being on average 265 mm long and 6 mm wide. The glued surface is fitted to the curves of the belly, although some luthiers shape it to a slightly tighter radius than the belly itself, known as ‘springing’, providing a certain amount of stress within the structure when glued in place. An undersized or badly positioned bar cannot provide sufficient stiffness to the front of the instrument and results in a dull, unfocussed sound (particularly in the bass register) and, in extreme cases, deformation and eventual collapse of the arching. Conversely, an oversized bar can stifle the sound, making the instrument unresponsive.
The bass-bar developed as a way of making bowed instruments more responsive by allowing the belly to be made thinner yet still be strong enough where it is needed to withstand the downward pressure of the strings. A painting by Raphael (Allegory of St Cecilia, c1514–16; see Viol, fig.7) shows an early viol with an enormously thick belly, which would presumably have had a rather limited sound. Early instruments were made with the bass-bar carved integrally with the belly rather than glued in separately, often in a central position. This practice continued in some areas outside the classical Italian tradition well into the 18th century, although with the bar closer to the modern position near the bass foot of the bridge. At what point the bass-bar migrated away from the centre is not clear. A bass viol from the late 16th century with a central bar is in the Ashmolean Museum, Oxford, ascribed to Gasparo da Salò of Brescia, but the earliest violin bass-bar recorded is from 1621, made by the brothers Antonio and Girolamo Amati in Cremona, and was separately fitted in the offset position.
Early bass-bars were fairly small. The 1621 example is some 5 mm lower than modern practice and 1·5 mm narrower, although it is slightly longer than a modern bar. Bass-bars from early 18th-century violins are shorter than the 1621 model, but with the same height and width and are generally flat along the length. By the late 18th century the bar acquired more mass and a ‘hump-backed’ shape, and this tendency continued into the 20th century, following the increased demands for projection and depth of sound in modern concert performance.
W.H., A.F., and A.E. Hill: Antonio Stradivari: His Life and Work (London, 1902/R, 2/1909/R)
D.D. Boyden: Catalogue of the Hill Collection of Musical Instruments in the Ashmolean Museum (Oxford, 1969)
J. Beamont: The Violin Explained: Components, Mechanism, Sound (Oxford, 1997)
JOHN DILWORTH