Classical guitar making


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

Skills

In general one can distinguish three main aspects of guitar making:
  1. "Sound" feature that includes shaping the wood.
  2. "Playability" aspects
This includes the shaping of the frets, string-spacing, neck-width, neck, nut and bridge height ; decisions about scale-length; etc.
The aim is a guitar that is easy and comfortable to play, does not have string-buzz, and suits the requirements/desires of a particular player.
  1. "Visual/decorative" aspects
This includes the visual features of the guitar, including rosette design, inlays, ornamentation, etc..
Fernando Sor has written that an instrument-maker "should be an accurate draughtsman, understand the common principles of mechanics, the composition and resolution of forces, and the laws of vibrating strings and surfaces".
- Engraving by Pierre Woeiriot

Viva fui in sylvis, sum dura occisa securi,
dum vixi, tacui, mortua dulce cano''

Shaping of wood with acoustics and resonance aims

This shaping of the wood is known as "resonance plate tuning". It refers to a comprehensive tuning of the wood and bracing to influence the acoustic properties. It does not refer to a tuning of the guitar-body to a single "default" frequency. Instead, it is a comprehensive way of shaping the wood and its response and resonance properties to improve the guitar's sound. The "tuning" of the wood is also called "voicing" the instrument. The techniques used trace to previous centuries, especially in violin-making.
Some guitarmakers believe that the actual voicing of the wood, and working with and "shaping" the wood is more important than the outer construction itself :
"As my skill and experience have grown I have come to believe that what makes a good guitar good is firstly how well fine tuned and balanced it is rather than what type of strutting system it is built with. Different strutting systems can add different flavours to the sound but is never the main factor in the Good Guitar."

Sound characteristics (Timbre)

Spectrum

One of the important aspects that good luthiers need to understand, is that a single tone consists of the "fundamental and simultaneous overtones". The ratio of the "intensity of fundamental" and the various overtones, defines the "colour" of the tone. Overtones are simply frequencies that are at a multiple of the base fundamental frequency.
Tonal colour is an important characteristic on a guitar. Usually the notes of the guitar's different registers have different colour-spectrums, i.e., differing relative intensities of fundamental to different overtones.
Various types of guitars have tone-differences in the various registers. Specific colour-spectrum characteristics of certain types of guitars can be said to form a specific "sound aesthetic"—this is like a "fingerprint" of the characteristic of that type of guitar. Other guitars have a different "sound aesthetic", i.e., a different colour-spectrum characteristic. Different historic instruments reflect various sound aesthetics.

Temporal change of spectrum (attack/onset, decay)

Important in characterizing the sound of instruments, is how the player initiates the sound. This is the attack or onset: a short-duration transient. This occurs at the moment when a string is plucked - the string builds up motion for some time, before it can vibrate in the normal way. The attack is nonlinear and usually has very high-pitched frequencies present. The duration of the transient and frequencies occurring during the transient, are a very important factor in how we perceive the tone.
Once the string is in its normal mode of vibration, the standard colour-spectrum is present. As time progresses the amplitude of the vibrations decreases, and usually the intensities of higher pitched overtones decay at a faster rate than the intensities of fundamental and lower overtones.
In this way one can observe the acoustic "envelope": the attack, followed by the way the intensity of frequencies decrease with time. The "envelope" can thus be regarded as the temporal change of the spectrum of the sound. This envelope is different for notes in different registers.
Thus the tone or timbre is determined by:
These factors can be influenced by the shaping of the wood. A good luthier understands how to shape the wood to directly influence these acoustic properties.
Guitar players can actively vary the timbre by the way they pluck the string—by changing the nail or finger angle, the distance from the bridge, etc. A good instrument helps the musician produce widely varying timbres and have yet have good resonance. Nevertheless, a default colour and response is identifiable for notes in the different registers and define the instrument's sound.

Styles of "sound aesthetic"

As was mentioned, it is possible to group historic instruments according to the colour and response sound characteristic. A baroque guitar has a different "sound aesthetic" than a 19th-century guitar, i.e. a differing colour-spectrum in the various registers and a different duration of attack.
The "sound aesthetic" is determined by the sound characteristic of notes in specific registers.
There is a historical parallel between musical styles and the style of "sound aesthetic" of the musical instruments used: Robert de Visée played on a baroque guitar with a very different sound aesthetic than the guitars used by Mauro Giuliani or Luigi Legnani - they used 19th-century guitars.
Whilst the difference between baroque guitars and 19th-century guitars is large and immediately obvious, one can also identify differences in style within the 19th-century guitars themselves: They are part of the same family, but one can distinguish early Italian instruments, then French instruments and Viennese instruments, etc.

Guitar making in the 19th century

To get a picture some of the ideas on guitar-building from the 19th century, some newspaper reports of guitar-related patents and other newspaper writings are listed:
There are also 19th-century mentionings of Lacôte winning a prize for the quality of his instrument - the second prize went to Laprevotte. In the competition organized by Makaroff, it was the guitar of Scherzer that took first place.
Guitars in the 19th century were initially all ladder-braced and had their tonal energy spread over a lot of overtones, as opposed to the more fundamental-rich guitars of Torres. Francisco Sanguino was one of the first to experiment with fan-bracing, then came Páges and Panormo—but Torres did not use it, so Panormo and Páges still had more tonal energy spread over overtones, compared to the Torres guitars, which focus tonal energy more in the fundamental.

Movable frets

To solve all guitar intonation problems, or help guitarists use different musical temperaments it is necessary for the frets on the guitar to be adjustable. Work in this field began in the 19th century, when Thomas Perronet Thompson wrote a work on the Enharmonic Guitar, with ideas used by Panormo. Lacôte also built a "guitare enharmonique" with movable frets.
The luthier Walter J. Vogt developed a contemporary mechanism with movable frets, now also used by other luthiers e.g. Herve R. Chouard. Tolgahan Cogulu has also designed an "adjustable microtonal guitar" in 2008, based on Vogt's design.
Other concepts for changeable frets, include removable detachable fingerboards: "switchboards".
See also: by John Schneider

Contemporary classical guitar making

The basis of most modern classical guitar designs was developed by Spanish luthier Antonio Torres Jurado in the mid-19th century. Earlier guitars were often smaller bodied. Torres created a Spanish design, with light materials supported by fan bracing. Torres' fan bracing was influential for modern classical guitars: it consists of wooden strips glued inside the body to provide support and particular deep resonance that is saturated in fundamental. Torres used a string scale-length of 650 mm, which is usually the standard length for today's modern classical guitars.
The designs Torres developed were later adapted by several very influential luthiers; Manuel
Ramirez and his brother José Ramírez, Hermann Hauser, Sr. and Ignacio Fleta. Today, luthiers use the ideas and designs of Torres, Hauser, and Fleta in their own guitars. Some luthiers experiment with their own bracing, and some also offer cutaway, acoustic electric and composite top models.
For years, Brazilian Rosewood was the industry standard as the best wood for the backs and sides of guitars. Unfortunately, the export of Brazilian Rosewood has been restricted due to the endangerment of the species. Much of the Brazilian Rosewood used for guitars is of poor quality, and the inflated price of the wood has caused many luthiers to search for alternative tonewoods. There are many other good very dry woods for guitar construction. In fact, of the surviving Torres instruments, the most common back and side wood used was maple. Many guitars made today use East Indian Rosewood because it is a close substitute for Brazilian Rosewood, is readily available in high-quality, and has desirable characteristics as tonewood. There are many other woods with the characteristics to make excellent guitars and are excellent alternatives: cocobolo, maple, bubinga, African Blackwood, Camatillo Rosewood, Spanish Cypress, granadillo, ebony, satinwood, ziricote, among others, are excellent choices for backs and sides.

Contemporary Innovations

Lattice braced guitars

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 is well known for building the guitars played by John Williams. A large number of luthiers worldwide have incorporated Smallman's design innovations into their own guitars.

Double-top, sandwich-top and composite-top

The terms double-top, sandwich-top, and composite-top all refer to a relatively new way to construct the soundboard of a guitar, developed by Matthias Dammann in Germany in the late 1980s. Other luthiers such as Robert Ruck, Fritz Mueller, Jim Redgate, Michel Bruck, Boguslaw Teryks and Gernot Wagner have since adopted the method. A double top usually consists of a material called Nomex sandwiched by two thin sheets of tonewood. A flame resistant meta-aramid material, Nomex was originally designed by DuPont Chemical Co. in the 1960s as a lightweight material for use in the aviation industry. Luthiers use the honeycomb sheet version of the product: the low mass, strength, and ease of shaping make it ideally suited for guitar soundboards. Though the construction of a double top significantly differs from the traditional soundboard, a double top guitar often looks just like a traditional guitar. A thin soundboard is often incorporated and used to obtain the most vibration and to allow for optimal sound.

Criticism of Lattice Bracing, Double Tops, etc.

While some people are positive towards innovations that directly affect a guitar's loudness, prefer the full round bodied tone, change in tone that can come with it, and feel that the loudness of some of these guitars is a by-product of their musical qualities rather than an end in itself; there are also a number of people who are generally critical of the tonal qualities of these guitars; why should guitar makers devote so much time in producing loud guitars with a thin sound, when the vast majority of guitarists do not need an exceptionally loud guitars?

Side Soundport

A number of luthiers are now incorporating a soundport, an additional small soundhole on the guitar's side, usually facing the player. This is said to allow air to move more freely in and out of the body of the guitar as it is vibrating, and to have the advantage of allowing the player to better hear the sound projecting from the guitar. The only published formal research on the latter subject suggests however that players may not be able to hear any difference in a soundport equipped guitar.

Finger board

Improvement of intonation and playability.

Elevated fingerboard

Some guitar makers like American Thomas Humphrey, Italian guitarmaker Renato Barone, Frenchman Antoine Pappalardo, and the Canadian Fritz Mueller, make elevated fingerboard guitars. The primary advantage is to improve left hand playability on the upper frets, although the increased distance between the strings and the top is also advantageous for the right hand. The elevated fingerboard is visually unobtrusive from the front, and the instrument retains its traditional appearance.

Curved fingerboard

Some guitar makers like the French Antoine Pappalardo make a Curved fingerboard to improve the playability.

High frets

High frets facilitate vibrato and barreing, and generally aid in the development of a "lighter" left hand.

Multiple scale length fretboards

The 17th-century wire-strung instruments, Orpharion and Bandora are early examples of instruments featuring multiple scale fretboards.

Armrest

An armrest provides three primary benefits: it lessens damping of the top caused by the right forearm; it is potentially more comfortable for the player; and it absorbs the wear to the finish that would otherwise happen on the top, the binding, and the side. These benefits are of particular importance for ultra-thin-topped instruments, such as Smallman's, but could subtly improve any guitar, including double-tops.

The state of classical guitar making

While most classical guitar makers are today mainly concerned with making modern classical guitars with their typical fan-bracing or experimenting to make the instrument louder ; they seem to give little consideration to historical sound ideals, or to tuning and voicing of the parts of the instrument.
On the other hand, there are opinions that those guitar makers who openly refer to using plate tuning, may be using it more as a marketing gimmick, than something that they truly understand; and has a marked influence on the instrument's sound.
And yet: plate tuning is a significant part of violin-making culture—recently considerable advances have been made in the voicing of violins, so that modern violins by some makers are finally beginning to compete tonally with the best violins of the past. In fact, top violinists who traditionally played Stradivari, are now slowly beginning to use modern violins. Making an exact copy does not guarantee an instrument with sound qualities identical to the original. There is, however, some evidence that violinists may be under some similar self-delusion as regards the end result of these efforts on the finished violin.
Thus, while some consider that in this respect, that guitar making today is still lagging behind professional violin-making, the scientific evidence is ambiguous, at best.
In violin culture many good old master-violins have been analyzed for their sound qualities.
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In guitar making, it is in many cases more difficult to find similarly idealized instruments for a number of reasons:
The de facto standard classical guitar today is the Spanish guitar: usually fan-braced and strong in fundamental. While fan-braced Spanish instruments coexisted with traditional central European ladder-braced guitars at the beginning of the 20th century, the central European guitars eventually fell away. Some attribute this to the popularity of Segovia, considering him "the catalyst for change toward the Spanish design and the so-called 'modern' school in the 1920s and beyond". The styles of music performed on ladder-braced guitars, were becoming more and more unfashionable; and e.g. in Germany musicians were in part turning towards folk-style music, which only remained localized in Germany, etc. On the other hand, Segovia was concertizing around the world popularizing his Spanish guitar, as well as a new style of music in the 1920s: Spanish romantic-modern style, with guitar works by Moreno Torroba, de Falla, etc.
In fact, Segovia's Santos Hernandez guitar from 1912, has a slightly different sound aesthetic, than the earlier Torres design. While the Torres is a guitar that some consider more appropriate to the salon style music of Tarrega, Arcas or Llobet, the later romantic-modern style of Moreno Torroba, Castelnuovo-Tedesco, etc.—combined with requirements of performing in large concert halls—was uniquely suited to Segovia's performance on the Santos Hernandez and later on the numerous Hauser guitars that he owned.
Yet "Andrés Segovia presented the Spanish guitar as a versatile model for all playing styles", to the extent that still today, "many guitarists have tunnel-vision to the world of guitar, coming from the modern Segovia tradition of revisionism".
Torres and post-Torres style modern guitars with their fan-bracing, have a thick and strong tone: but they are considered too saturated in fundamental for earlier repertoire.
Torres and post-Torres guitars have a strong thick sound.
The sound aesthetic of early romantic guitars on the other hand, has stronger overtones. This stronger overtone presence is due to the ladder-bracing and soundboard design, and the particular voicing of the instrument. A comparison with lutes can be made, which also have strong overtones, which gives these instruments a type of "inner" vulnerability, lacking in the modern guitars.
Even amongst parlor guitar players, there are some that consider ladder bracing necessary, for achieving the desired "old-time sound".
With an increase in interest in historically informed interpretation, there are more and more luthiers that are beginning to look at traditions of guitar building.

Some contemporary luthiers suggest building historic instruments based not only on outer visual details, but based on acoustic principles from master luthiers of the 17th and 18th centuries, leaning towards and learning from the great makers. Drawing a parallel to violin-making culture, and lutherie as a broader art, it might be interesting to deriving indications for the possible aims and ideals of "sound aesthetic in guitars" from other instruments, which would open up the possibility of tonally competing with luthiers from earlier periods, instead of only visually imitating and copying them.