Bridge (instrument)
The bridge conducts the vibrations of the strings to a hollowed out chamber in a number of instruments (e.g., violin family, acoustic guitar, balalaika).
Depending on the type of stringed instrument, the resonant surface the bridge rests on may be made of: Bridges may consist of a single piece of material, most commonly wood for violins and acoustic guitars, that fits between the strings and the resonant surface.
One common form is a bridge with a separate bearing surface, called a saddle, that supports the strings.
A classical guitar saddle sits loosely in the hardwood bridge, held in place by string tension.
Yet another type of multi-part bridge is common on instruments with a curved sound plate, such as an arch-top guitar or mandolin.
They are usually made of steel in modern pianos, of brass in harpsichords, and bone or synthetics on acoustic guitars.
Most violin-family bridges are carved by a luthier; as such, the height can be changed, but only by taking the violin into the repair shop.
The nut, at the opposite end of the instrument from the bridge or tailpiece (typically where the head holding the tuning pegs joins the fingerboard), serves a similar string-spacing function.
Bridges for electric guitars can be divided into two main groups, "vibrato" and "non-vibrato" (also called "hard-tail").
It acts as a lever that the player can push or pull to change the strings' tension and, as a result, "bend" the pitch down or up.
A whammy bar bridge is important in some heavy metal music styles, such as shred guitar.
Most vibrato system designs use a group of springs in the guitar body, which oppose the tension of the strings.
Some players feel that the vibration of the springs affects resonance in a way that makes the guitar sound better, but others disagree.
feel that they can also provide a better degree of sound transfer, especially with tailpiece type tremolos such as the Bigsby lever used on vintage instruments.
A locking tremolo uses a bridge that has a small clamp in each saddle to hold the strings in place (usually adjusted with an Allen key).
Assuming the bridge is of good quality[clarification needed], it limits longitudinal string movement, providing tuning stability.
The improved transfer of string vibration into the body has an effect on the sound, so guitars with this type of bridge have different characteristics than those with tremolos, even when removed.
