A bridge is a device that supports the
strings on a
stringed musical instrument and transmits the
vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic, such as the motion of a pendulum—or random, su ...
of those strings to another structural component of the instrument—typically a
soundboard, such as the top of a guitar or violin—which transfers the
sound
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.
In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by ...
to the surrounding air. Depending on the instrument, the bridge may be made of carved wood (
violin family
The violin family of musical instruments was developed in Italy in the 16th century. At the time the name of this family of instruments was viole da braccio which was used to distinguish them from the viol family (viole ''da gamba''). The stan ...
instruments,
acoustic guitar
An acoustic guitar is a musical instrument in the string family. When a string is plucked its vibration is transmitted from the bridge, resonating throughout the top of the guitar. It is also transmitted to the side and back of the instrument, ...
s and some
jazz guitar
Jazz guitar may refer to either a type of electric guitar or a guitar playing style in jazz, using electric amplification to increase the volume of acoustic guitars.
In the early 1930s, jazz musicians sought to amplify their sound to be he ...
s), metal (
electric guitar
An electric guitar is a guitar that requires external amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar (however combinations of the two - a semi-acoustic guitar and an electric acoustic gu ...
s such as the
Fender Telecaster) or other materials. The bridge supports the strings and holds them over the body of the instrument under tension.
Explanation
Most stringed instruments produce sound through the application of
energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of ...
to the strings, which sets them into vibratory motion, creating musical sounds. The strings alone, however, produce only a faint sound because they
displace only a small volume of air as they vibrate. Consequently, the sound of the strings alone requires
impedance matching to the surrounding air by transmitting their vibrations to a larger surface area that displaces a larger volume of air (and thus produces louder sounds). This calls for an arrangement that lets the strings vibrate freely, but also conducts those vibrations efficiently to the larger surface. A bridge is the customary means for accomplishing this. The bridge conducts the vibrations of the strings to a hollowed out chamber in a number of instruments (e.g.,
violin family
The violin family of musical instruments was developed in Italy in the 16th century. At the time the name of this family of instruments was viole da braccio which was used to distinguish them from the viol family (viole ''da gamba''). The stan ...
,
acoustic guitar
An acoustic guitar is a musical instrument in the string family. When a string is plucked its vibration is transmitted from the bridge, resonating throughout the top of the guitar. It is also transmitted to the side and back of the instrument, ...
,
balalaika).
On
electric guitar
An electric guitar is a guitar that requires external amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar (however combinations of the two - a semi-acoustic guitar and an electric acoustic gu ...
s and electric basses, the bridge conducts the vibrations to the body, but the vibrations of the strings are typically sensed by a
magnetic pickup, so that an electric signal is created, which is then connected to a
guitar amplifier and a
speaker enclosure to produce the sound the performer and audience hears. On
electric pianos, the player presses or strikes keys, which cause hammers to strike metal tines. A magnetic pickup senses these vibrations, using the same approach as with an electric guitar (amplifier and speaker).
Positioning
Typically, the bridge is perpendicular to the strings and larger surface (which are roughly parallel to one another) with the
tension of the strings pressing down on the bridge and thus on the larger surface beneath it.
That larger, more acoustically responsive surface may be coupled to a sound chamber—an enclosure such as the body of a
guitar
The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected string ...
or
violin
The violin, sometimes known as a '' fiddle'', is a wooden chordophone ( string instrument) in the violin family. Most violins have a hollow wooden body. It is the smallest and thus highest-pitched instrument ( soprano) in the family in regu ...
—that provides resonance that helps amplify the sound.
Depending on the type of stringed instrument, the
resonant surface the bridge rests on may be made of:
* Wood, as the top "plate" piece of wood of a
guitar
The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected string ...
or
violin
The violin, sometimes known as a '' fiddle'', is a wooden chordophone ( string instrument) in the violin family. Most violins have a hollow wooden body. It is the smallest and thus highest-pitched instrument ( soprano) in the family in regu ...
* Calfskin or plastic under tension, as with a
drum
The drum is a member of the percussion group of musical instruments. In the Hornbostel-Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a ...
, as on the head of a
banjo
The banjo is a stringed instrument with a thin membrane stretched over a frame or cavity to form a resonator. The membrane is typically circular, and usually made of plastic, or occasionally animal skin. Early forms of the instrument were fashi ...
* Metal, as on certain types of resophonic fretted instruments
* Virtually any material that can vibrate sympathetically with the strings. Some
upright basses are made of aluminium. Some
violin family
The violin family of musical instruments was developed in Italy in the 16th century. At the time the name of this family of instruments was viole da braccio which was used to distinguish them from the viol family (viole ''da gamba''). The stan ...
instruments are made of carbon fibre.
Construction
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. Alternatively, a bridge may consist of multiple parts. One common form is a bridge with a separate bearing surface, called a ''saddle'', that supports the strings. This is often of a material harder than the bridge itself, such as bone, ivory, high-density plastic, or metal. Some acoustic guitar bridges have multiple materials, such as a bridge support and "feet" made of wood and a plastic or bone "ridge" where the strings are positioned against.
A classical guitar saddle sits loosely in the hardwood bridge, held in place by string tension. Strings pass through shallow grooves in the saddle, at least for the treble strings, which prevents them moving around during hard playing.
Yet another type of multi-part bridge is common on instruments with a curved sound plate, such as an arch-top
guitar
The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected string ...
or
mandolin
A mandolin ( it, mandolino ; literally "small mandola") is a stringed musical instrument in the lute family and is generally plucked with a pick. It most commonly has four courses of doubled strings tuned in unison, thus giving a total of ...
. Such instruments often have a bridge with a base and separate saddle that can be adjusted for height. On classical and
flat-top guitar
A flattop is a type of haircut where the hair on the top of the head is cut and styled upright to form a flat profile when viewed from the front or side.
Styling
In the most classic and mainstream style of flattop for men and boys, the hair ...
s the bridge is glued to the top. A bridge held on to the top by string tension, as in banjos and archtop
jazz guitar
Jazz guitar may refer to either a type of electric guitar or a guitar playing style in jazz, using electric amplification to increase the volume of acoustic guitars.
In the early 1930s, jazz musicians sought to amplify their sound to be he ...
s, is called a ''floating bridge'', and requires a separate tailpiece to anchor the strings.
Electric guitar
An electric guitar is a guitar that requires external amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar (however combinations of the two - a semi-acoustic guitar and an electric acoustic gu ...
s typically have a metal bridge, often with adjustable
intonation screws.
Bridge pin
Bridge pins or string pegs are used on some musical instruments to locate the
string precisely in the horizontal plane, and in the case of harpsichords to affect the
sustain of the strings. They are usually made of steel in modern
piano
The piano is a stringed keyboard instrument in which the strings are struck by wooden hammers that are coated with a softer material (modern hammers are covered with dense wool felt; some early pianos used leather). It is played using a keyboa ...
s, of brass in
harpsichord
A harpsichord ( it, clavicembalo; french: clavecin; german: Cembalo; es, clavecín; pt, cravo; nl, klavecimbel; pl, klawesyn) is a musical instrument played by means of a keyboard. This activates a row of levers that turn a trigger mechanism ...
s, and bone or synthetics on acoustic
guitars
The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected strin ...
. Electric guitars do not usually have bridge pins as with guitars, they are used to transfer the sound from the strings into the hollow body of the instrument as well as holding the strings in place.
In pianos the pins are set precisely in line with the edges of the notches of the bridge. The precise and firm setting of the pins is a critical element of the piano's quality. Loose or inaccurate pinning commonly produces false beats and tonal irregularities.
In harpsichords there tends to be a significant distance instead. This enables control of sustain and tone in harpsichord design (as per external link).
For the larger, deeper violin family instruments, the bridge pin may have an extendable "
endpin" which raises the instrument up.
Tie block
The bridge of the classical guitar does not use bridge pins. In this instrument the strings are tied to the part of the bridge called the tie block. Strings run over the bridge saddle, through drilled holes in the base of the tie block, loop over the top of the tie block, loop under the strings and are tied on. A variation called the 18 hole bridge uses three holes per string and eliminates the need to tie the string down.
Operation
The bridge must transfer vibration of the strings to the
sound board or other amplifying surface. As the strings are set in motion (whether by picking or strumming, as with guitars, by bowing, with violin family instruments, or by striking them, as with pianos), the bridge bends to and fro along the string direction at twice the rate of the string vibration. This causes the sounding board to vibrate at the same frequency as the string producing a wave-like motion and an audible sound. Instruments typically use a hollow, resonant chamber (violin bodies, guitar bodies) or a pickup and an amplifier/speaker to make this sound loud enough for the performers and audience to hear.
Bridges are designed to hold the strings at a suitable height above the
fingerboard
The fingerboard (also known as a fretboard on fretted instruments) is an important component of most stringed instruments. It is a thin, long strip of material, usually wood, that is laminated to the front of the neck of an instrument. The s ...
of the instrument. The ideal bridge height creates sufficient angularity in the string to create enough down force to drive the top, but places the strings sufficiently close to the fingerboard to make noting the strings easy. Bridge height may be fixed or alterable. Most violin-family bridges are carved by a
luthier
A luthier ( ; AmE also ) is a craftsperson who builds or repairs string instruments that have a neck and a sound box. The word "luthier" is originally French and comes from the French word for lute. The term was originally used for makers of ...
; as such, the height can be changed, but only by taking the violin into the repair shop. Many acoustic guitars have fixed bridges that a regular player cannot adjust. Some
jazz guitar
Jazz guitar may refer to either a type of electric guitar or a guitar playing style in jazz, using electric amplification to increase the volume of acoustic guitars.
In the early 1930s, jazz musicians sought to amplify their sound to be he ...
s have a "floating bridge" which the player can reposition themself for different sounds and tones.
In addition to supporting the strings and transmitting their vibrations, the bridge also controls the spacing between strings with shallow grooves cut in the bridge or its saddle. The strings sit in those grooves, thus are held in their proper lateral position. 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. As well, like the bridge, the nut's height determines how high the strings are from the fingerboard.
Electric guitar bridges
Bridges for electric guitars can be divided into two main groups, "
vibrato" and "non-vibrato" (also called "hard-tail").
Vibrato bridges have an arm or lever (called the vibrato arm, tremolo arm, or "whammy bar") that extends from below the string anchoring point. It acts as a
lever
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or '' fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is d ...
that the player can push or pull to change the strings'
tension and, as a result, "bend" the
pitch down or up. This means that this type of bridge produces
vibrato (a pitch change) rather than actual
tremolo, but the term "tremolo" is deeply entrenched in popular usage via some manufacturers (starting with
Fender Stratocaster in 1954
) naming their vibrato systems as "tremolo".
Non-vibrato bridges supply an anchoring point for the strings but provide no active control over string tension or pitch. That is, there is no "whammy bar" or lever. A small group of vibrato bridges have an extended tail (also called "longtail"). These guitars have more reverb and sustain in their sound, because of the string resonance behind the bridge. The
Fender Jaguar
The Fender Jaguar is an electric guitar by Fender Musical Instruments characterized by an offset-waist body, a relatively unusual switching system with two separate circuits for lead and rhythm, and a short-scale 24" neck. Owing some roots to ...
is an example of such a guitar.
All bridges have advantages, and disadvantages, depending on the playing style, but, in general, a non-vibrato bridge is thought to provide better tuning stability and a solid contact between the guitar body and the strings. A whammy bar bridge is important in some
heavy metal music
Heavy metal (or simply metal) is a genre of rock music that developed in the late 1960s and early 1970s, largely in the United Kingdom and United States. With roots in blues rock, psychedelic rock and acid rock, heavy metal bands develope ...
styles, such as
shred guitar.
Vibrato bridges
Generally, the more
contact
Contact may refer to:
Interaction Physical interaction
* Contact (geology), a common geological feature
* Contact lens or contact, a lens placed on the eye
* Contact sport, a sport in which players make contact with other players or objects
* C ...
the bridge has with the body (i.e., the lower the position), the better the sound transfer is into the body. A "warmer" sound with increased sustain is the result. Vibrato bridges usually must be suspended in some way, which reduces contact. 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
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 oscil ...
in a way that makes the guitar sound better, but others disagree. Many electric guitar playing styles require a vibrato system, either "locking" or "non-locking".
Non-locking tremolo/vibrato systems
Non-locking (or vintage) tremolos are the bridges found on guitars manufactured prior to the advent of the
Floyd Rose locking tremolo in the late 1970s and many (typically cheaper) guitars manufactured thereafter. For many playing styles, vintage tremolos are a good choice because they are easy to use and maintain and have very few parts. Some people 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. However, the "Synchronized Tremolo" type found on the
Fender Stratocaster is balanced against a set of screws in much the same manner as a locking tremolo. Given that this type of tremolo is installed on solid body guitars the degree to which sound transfer affects the sound that the instrument produces is minimal.
Also, keeping a guitar with a non-locking tremolo in tune can be difficult. The most common types of non-locking tremolos are the "Synchronized Tremolo" type and an almost endless stream of copies. The
Bigsby vibrato tailpiece
The Bigsby vibrato tailpiece (or Bigsby for short) is a type of mechanical vibrato device for electric guitar designed by Paul Bigsby and produced by the Bigsby Electric Guitar Company (currently an independently operated subsidiary of Fend ...
is another option.
Locking tremolo/vibrato systems
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
Hex keys of various sizes
Socket head screws of various sizes
A hex key (also, hex wrench, Allen key and Allen wrench) is a simple driver for bolts or screws that have heads with ''internal'' hexagonal recesses (sockets).
Hex keys are form ...
). The
nut at the end fingerboard also clamps the strings to hold them in place. This arrangement is especially useful for playing that requires tapping or heavy "bending" playing styles, such as
shred guitar "dive bombing" effects. Locking tremolos provide excellent stability, but their fulcrum points provide minute contact with the body, which might disturb sound transfer.
Non-Tremolo/vibrato bridges
It is generally thought that non-tremolo bridges offer better transfer of string vibration into the body. This is due to direct contact of the bridge to the guitar's body. These bridges bolt directly to the guitar body. Assuming the bridge is of good quality, 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. There are no springs in the body or a cavity to accommodate them, which also affects resonance.
See also
*
Fingerboard
The fingerboard (also known as a fretboard on fretted instruments) is an important component of most stringed instruments. It is a thin, long strip of material, usually wood, that is laminated to the front of the neck of an instrument. The s ...
*
Electronic tuner Some tuners attach to the bridge of an instrument.
*
Nut (string instrument)
References
*A.B.Wood (Admiralty Research Laboratory), A Textbook of Sound, Publ Bell, 3rd ed. 1955. No ISBN found.
External links
violinbridges.co.uk Online bridge archiveMovement in Tune-O-Matic bridges
{{Violin family
String instrument construction