Guitar bracing

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Guitar bracing refers to the system of wooden struts which internally support and reinforce the soundboard and back of acoustic guitars.


Soundboard or top bracing transmits the forces exerted by the strings from the bridge to the rim. The luthier faces the challenge of bracing the instrument to withstand the stress applied by the strings with minimal distortion, while permitting the top to respond as fully as possible to the tones generated by the strings. Brace design contributes significantly to the type of sound a guitar will produce. According to luthiers W. Cumpiano and J. Natelson, "By varying brace design, each builder has sought to produce a sound that conformed to his concept of the ideal." [1]

The back of the instrument is braced to help distribute the force exerted by the neck on the body, and to maintain the tonal responsiveness and structural integrity of the sound box.


Braces may be made from top woods (spruce or cedar), balsa wood or, in high-end instruments, carbon fiber composites.

Nylon string guitar bracing

Fan bracing

This is the standard bracing pattern on the classical guitar, dating to the work of Antonio Torres Jurado in the 19th century.

Kasha Bracing

In the 1970s, scientist Michael Kasha radically overhauled every aspect of guitar design to incorporate principles such as mechanical impedance matching. [2]

Lattice bracing

The Australian guitarmaker Greg Smallman introduced guitars with an extremely thin soundboard, which is supported by bracing in the shape of a lattice. Smallman combines this with heavier, laminated back and sides with a frame. Smallman's guitars are used by John Williams.

Smallman's design was inspired by research by Torres who made a guitar with a papier mâché back and sides to show that the soundboard was the most important factor in guitar sound projection. Smallman also uses two 45 degree pole supports in the frame running from the bottom of the guitar to the waist to prevent the string tension from distorting the body and sound board.

Steel string flat-top guitar bracing

In all steel-string instruments, the ends of the top braces taper at the edge of the soundboard. In most factory built guitars the brace tops are given a round profile, but are otherwise left unshaped. This produces a stronger top and may reduce the number of warranty claims arising from damage, however, over-built tops are less responsive. [3] Braces are usually made from Sitka Spruce (Picea sitchensis). [4] Some luthiers use Adirondack Spruce, also known as "Red Spruce" (Picea rubens), in high end instruments.


The tops of most steel string acoustic guitars are braced using the X-brace system, or a variation of the X-brace system, generally attributed to Christian Frederick Martin between 1840 and 1845 for use in gut string guitars. [5] [6] The system consists of two braces forming an "X" shape across the soundboard below the top of the sound hole. The lower arms of the "X" straddle and support the ends of the bridge. Under the bridge is a hardwood bridge plate which prevents the ball end of the strings from damaging the underside of the soundboard. Below the bridge patch are one or more tone bars which support the bottom of the soundboard. These abut one of the X braces and usually slant down towards the bottom edge of the soundboard. The top tone bar butts against a portion of the bridge patch in most instruments. Above the sound hole a large transverse brace spans the width of the upper bout of the soundboard. Around the lower bout, small finger braces support the area between the X-braces and the edge of the soundboard.

Double X-bracing

In this system, two overlapping X shapes form a diamond surrounding the underside of the bridge plate. Some luthiers prefer it where additional strength is required, for instance for twelve string guitars. This bracing does not allow the top to move or vibrate as much as it normally would but offers more strength and prevent bellying around the bridge area.


Several bracing styles are designated as A-bracing. Mottola's Cyclopedic Dictionary of Lutherie Terms [7] lists two. The first, typical of instruments built by Tacoma, use two long longitudinal struts that diverge from near the neck block to near the tail end of the guitar. This bracing style is used on instruments that feature a soundhole that is not centrally located. The second style listed is that used by some models of Ovation guitars, also called Adamas bracing. There is also a variation on X-bracing called A-bracing. The X-shaped structure under the bridge is retained, but the transverse strut between the fingerboard and soundhole is replaced by two diagonal braces which splay outward going toward the soundhole. It is used by Lowden Guitars.

V-Class Bracing

V-Class bracing is a bracing style developed by Andy Powers for Taylor Guitars. It is similar to A-bracing, however the main braces diverge across both sides of the sound hole towards the neck side of the top, and converge at the endblock to form the shape of a V. A lateral brace positioned between the soundhole and bridge plate spans the width of the top, and there are two sets of tone/finger braces between the bridge plate and endblock that are roughly perpendicular to the longitudinal V-braces and run from the V-brace towards the edge of the top. It is purported to allow the top to be both stiff and flexible in order to produce more volume and sustain. Taylor also purports that the design improves harmonic intonation. [8]

Falcate bracing

Falcate (sickle-shaped) bracing is a symmetric bracing style designed by luthier and engineer Trevor Gore, and used on his steel-string and classical nylon-string guitars. It claims a more even sound over the frequency spectrum, and more responsiveness and volume without being too delicate.

Brace shape and 'voicing' or 'tap tuning'

Luthiers building higher quality instruments adjust the stiffness of the top and shape the braces to maximize the response of the top while maintaining structural integrity. Tone bars and bottom halves of the X-braces may be either scalloped or parabolic in shape. Above the X-brace joint, braces usually have a parabolic shape. Experienced luthiers 'voice' or 'tap-tune' the tops and backs of high end guitars to produce optimum tone and responsiveness in the hands of the player. [9]

Scalloped vs parabolic bracing

Bracing style and shape will affect the tone of the instrument. According to luthiers Bob Connor and David Mainwaring, "scalloped braces will produce a warmer sounding bass response in the guitar with smooth mids and crisp highs. Parabolic braces will yield a quick response with a more pronounced mid range and a more focused bottom end." [10]

Ladder bracing

This simple system, where braces are arranged parallel to each other and perpendicular to the direction of the strings, is employed on most guitar backs. It was also once used on guitar tops, a practice which survives in the Maccaferri guitar. It is considered more suitable for parlor guitars and lightly strung instruments. [11]

Archtop bracing

Archtop guitars originally had two near-horizontal braces or "tone bars" on either side from bridge to neck, a system known as parallel bracing. The braces roughly run under the feet of the archtop guitar's bridge. X-bracing, similar to that of flat-top guitars was later introduced. Their tops are inherently stronger than flat tops, so less bracing may be required. "Trestle" bracing was a system used on some Gretsch archtops [12]

Related Research Articles

Steel-string acoustic guitar

The steel-string acoustic guitar is a modern form of guitar that descends from the nylon-strung classical guitar, but is strung with steel strings for a brighter, louder sound. Like the classical guitar, it is often referred to simply as an acoustic guitar.

Classical guitar member of the guitar family used in classical music

The classical guitar is a member of the guitar family used in classical music. An acoustic wooden string instrument with strings made of gut or nylon, it is a precursor of the modern acoustic and electric guitars, both of which use metal strings. Classical guitars are derived from the Spanish vihuela and gittern in the fifteenth and sixteenth century, which later evolved into the seventeenth and eighteenth-century Baroque guitar and later the modern classical guitar in the mid-nineteenth century.

Electric guitar Electrical string instrument

An electric guitar is a guitar that requires external amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar. It uses one or more pickups to convert the vibration of its strings into electrical signals, which ultimately are reproduced as sound by loudspeakers. The sound is sometimes shaped or electronically altered to achieve different timbres or tonal qualities from that of an acoustic guitar. Often, this is done through the use of effects such as reverb, distortion and "overdrive"; the latter is considered to be a key element of electric blues guitar music and rock guitar playing.

Guitar Fretted string instrument

The guitar is a fretted musical instrument that typically has six strings. It is held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected strings against frets with the fingers of the opposite hand. A plectrum or individual finger picks may be used to strike the strings. The sound of the guitar is projected either acoustically, by means of a resonant chamber on the instrument, or amplified by an electronic pickup and an amplifier.

Mandolin Musical instrument in the lute family

A mandolin is a stringed musical instrument in the lute family and is generally plucked with a plectrum. It most commonly has four courses of doubled metal strings tuned in unison, thus giving a total of 8 strings, although five and six course versions also exist. The courses are typically tuned in an interval of perfect fifths, with the same tuning as a violin. Also, like the violin, it is the soprano member of a family that includes the mandola, octave mandolin, mandocello and mandobass.

C. F. Martin & Company American guitar manufacturer established in 1833

C.F. Martin & Company is an American guitar manufacturer established in 1833, by Christian Frederick Martin. It is highly respected for its acoustic guitars and is a leading manufacturer of flat top guitars. The company has also made mandolins and as well as several models of electric guitars and electric basses, although none of these other instruments are currently in production.

Sound board (music)

A sound board, or soundboard, is the surface of a string instrument that the strings vibrate against, usually via some sort of bridge. Pianos, guitars, banjos, and many other stringed instruments incorporate soundboards. The resonant properties of the sound board and the interior of the instrument greatly increase the loudness of the vibrating strings. "The soundboard is probably the most important element of a guitar in terms of its influence on the quality of the instrument's tone [timbre]."

When the [guitar] top vibrates, it generates sound waves, much like a loudspeaker. As the soundboard moves forward, the air that is in front of it is compressed and it moves away from the guitar. As the soundboard moves back, the pressure on the air in front of the guitar is reduced. This is called a "rarefaction," and air rushes in to fill the rarefied region. Through this process, an alternating series of compression and rarefaction pulses travel away from the soundboard, creating sound waves.

The fingerboard 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 strings run over the fingerboard, between the nut and bridge. To play the instrument, a musician presses strings down to the fingerboard to change the vibrating length, changing the pitch. This is called stopping the strings. Depending on the instrument and the style of music, the musician may pluck, strum or bow one or more strings with the hand that is not fretting the notes. On some instruments, notes can be sounded by the fretting hand alone, such as with hammer ons, an electric guitar technique.

Archtop guitar Type of steel-stringed acoustic or semi-acoustic guitar

An archtop guitar is a hollow steel-stringed acoustic or semiacoustic guitar with a full body and a distinctive arched top, whose sound is particularly popular with jazz, blues, and rockabilly players.

The Ovation Guitar Company is a manufacturer of string instruments. Ovation primarily manufactures steel-string acoustic guitars and nylon-string guitars, often with pickups for electric amplification. In 2015, it became a subsidiary of Drum Workshop after being acquired from KMCMusicorp.

A sound hole is an opening in the body of a stringed musical instrument, usually the upper sound board. Sound holes have different shapes:

Octave mandolin

The octave mandolin is a fretted string instrument with four pairs of strings tuned in fifths, GDAE, an octave below a mandolin. It is larger than the mandola, but smaller than the mandocello and its construction is similar to other instruments in the mandolin family. Usually the courses are all unison pairs but the lower two may sometimes be strung as octave pairs with the higher-pitched octave string on top so that it is hit before the thicker lower-pitched string. Alternate tunings of GDAD and ADAD are often employed by Celtic musicians.

Flamenco guitar Acoustic guitar used in Flamenco music

A flamenco guitar is a guitar similar to a classical guitar but with thinner tops and less internal bracing. It usually has nylon strings, like the classical guitar, but it generally possesses a livelier, more gritty sound compared to the classical guitar. It is used in toque, the guitar-playing part of the art of flamenco.

A person who is specialized in the making of stringed instruments such as guitars, lutes and violins is called a luthier.

A flat top guitar is a type of guitar body model which has a flat top. The term "flat top" is usually used to refer to the most popular type of steel-string acoustic guitars; however, electric guitars such as the Fender Telecaster and the Gibson Les Paul Junior and Special can be described as "flat top".

Acoustic guitar

An acoustic guitar is a musical instrument in the guitar family. Its strings vibrate a sound board on a resonant body to project a sound wave through the air. The original, general term for this stringed instrument is guitar, and the retronym 'acoustic guitar' distinguishes it from an electric guitar, which relies on electronic amplification. Typically, a guitar's body is a sound box, of which the top side serves as a sound board that enhances the vibration sounds of the strings. In standard tuning the guitar's six strings are tuned (low to high) E2 A2 D3 G3 B3 E4.

Tacoma Guitars was an American manufacturing company of musical instruments. It was founded in 1991 as a division of South Korean company Young Chang. Instruments were manufactured in Tacoma, Washington. The company and brand name were later acquired by the Fender Musical Instruments Corporation. The Tacoma plant closed, and production ceased, in 2008.

William R. Cumpiano Puerto Rican master guitarmaker

William Richard Cumpiano is a builder of stringed musical instruments and is known for his writing and teaching of the art of luthiery. He has been involved in the preservation and understanding of the fading musical and musical craft traditions of his native Puerto Rico. Cumpiano was instrumental in the development of the first feature-length documentary about the cuatro and its music, Our Cuatro: The Puerto Ricans and Stringed Instruments, Volumes 1 and 2.

Bridge (instrument) Part of a stringed instrument

A bridge is a device that supports the strings on a stringed musical instrument and transmits the vibration 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 to the surrounding air. Depending on the instrument, the bridge may be made of carved wood, metal or other materials. The bridge supports the strings and holds them over the body of the instrument under tension.

Jeffrey Yong Malaysian Luthier (born 1958)

Jeffrey Yong is a Malaysian Luthier best known for his use of local Malaysian wood, such as monkeypod, rengas, mango, rambutan and Malaysian blackwood. The use of non-traditional wood to build musical instruments has not only placed Jeffrey Yong guitars in international markets but also as one of the top luthiers in the world. Jeffrey has gained international recognition and has been invited to exhibit his instruments in several international conventions.


  1. Guitarmaking Tradition and Technology by W.R. Cumpiano and J.D. Natelson p143
  2. Kasha guitar design
  3. Guitar Brace Repair article explains acoustic guitar brace design, construction, and repair on the Guitar Repair Bench Luthier Website
  4. Guitarmaking Tradition and Technology by W.R. Cumpiano and J.D. Natelson p146
  5. Guitarmaking Tradition and Technology by W.R. Cumpiano and J.D. Natelson p145
  6. During the 1850s, X-bracing was used by several makers, all German immigrants who knew each other, and according to historian, Philip Gura, there is no evidence that C.F. Martin invented the system. See Gura, Philip, F. - C. F. Martin and His Guitars, The University of North Carolina Press, Page 106
  7. Mottola, R.M. (1 January 2020). Mottola's Cyclopedic Dictionary of Lutherie Terms. p. 4. ISBN   978-1-7341256-0-3.
  8. Taylor V-Class Bracing Story
  9. The Luthier's Handbook by Roger H. Siminoff pp70,71
  10. "Archived copy". Archived from the original on 2009-09-14. Retrieved 2009-06-22.CS1 maint: archived copy as title (link)
  11. Brace repairs
  12. Trestle bracing