For most guitarist purchasing your first "real instrument" can be a confusing and nerve racking experience. Often guitarists find themselves spending more money than they feel comfortable parting with and not really understanding if they are getting a fair deal or not. This series of blog posts will hopefully help. The first few entries will deal with exclusively with the classical guitar, steel string acoustic and electric guitar will be covered in future posts so be sure to click that RSS button at the bottom of the page. This blog entry, as well as the next one, clear up a few points of confusion and provide some insight into the recent history of the classical guitar.
First it should be noted ……The so called “classical guitar” refers to the instrument not the music played on it. The classical guitar was used to distinguish the instrument from earlier iterations such as the baroque guitar and the five course guitar. The instruments bearing the moniker, Classical, all had six string of gut (now nylon), fretboards that extended all the way to the soundhole and met the body at the twelfth fret; among other characteristic features.
When considering the modern classical guitar there really have been two major periods of evolution. The first happened in the mid-nineteenth century and will be the focus of this blog post. The second, the more recent innovations gaining popularity since about the 1980’s, will be covered in the next blog entry.
The “classical guitar” as it has come to be known today, was largely developed by Antonio de Torres Jurado (1817–1892) in the mid-nineteenth century. This blog entry will examine exactly how Torres was able to build a “better” instrument than his contemporaries. To unearth such insights one must examine several factors: the manner in which a guitar produces sound, the materials used in the construction process, and the construction methods. This entry is intended to elucidate both the modifications made to the guitar’s construction by Torres and why some of these modifications produced a guitar of superior acoustical capabilities.
In order to understand why Torre’s modifications made his instruments superior to those of his contemporaries’ one must possess a clear understanding of how the guitar produces sound. Beyond the obvious fact that a string excited by being plucked or strummed, what actually happens to ultimately broadcast that excitement into the lush, robust, and “round” classical guitar tone? Ulrike G.K. Wegst, associate professor of Engineering at Dartmouth College and an expert in musical instrument materials, wrote “The sound that a single plucked or bowed string produces is barely audible because one string sets only a small volume of air into motion.” [1] In order to activate a larger volume of air luthiers must exploit a physical phenomenon known as “coupling.” This term, “refers to an interaction between two or more vibrating elements.” [2] The higher pitches are produced by the coupling of the string, the bridge, and the soundboard. Both the bridge and the soundboard are “loaded” with tension due the strings being tightened in order to attain proper pitch while tuning. This highly-tensed surface of the soundboard works well for producing the higher pitches put forward by the guitar. However the string, bridge, and soundboard alone produce a quite nasally-sounding tone reminiscent of romantic and baroque era chordophones. This coupled triumvirate does not create the warm tone modern listeners expect to hear.
The interaction looks roughly like this:
Figure 1
(High Frequencies) [3]
To produce the lower pitches one must also set the sides and back of the guitar in motion, which turns the high frequency vibrations into lower frequency vibrations derived from the coupling of air inside the body of the guitar, the sound hole, the sides, and back of the guitar. [4]
A diagram of this increased coupling can be seen in Figure 2 below. Joe Wolfe, professor of physics and a researcher of the physics of music and speech, calls this “a form of impedance matching.” [5]
Figure 2
(Low Frequencies) [6]
One can only fully understand the improvements made to the guitar by Torres after examining the guitars of his predecessors and contemporaries. Rather than undertaking the overwhelming task of examining all guitars of the era, focusing on instruments produced by the leading luthiers of the day allows one to understand the state of the art of the guitar building in Torres’ lifetime. Through instruments that remain from the era, as well quotes from top players of the day such as Fernando Sor, many guitarists consider the instruments of Louis Panormo, Johann Georg Stauffer, and Rene Lacote to be the instruments representative of the finest pre-Torres guitars. [7]
Figure 3 Five brace fan bracing
Louis Panormo was a second generation Luthier, born the fourth son of Vicenzo Panormo an Italian who had relocated to Paris. [8] He moved to London at age 25 and produced not only guitars but also violins, violas, cellos, and double basses. The guitars made by Panormo are much akin to the modern classical guitar. His guitars use five thin symmetrical fan struts as well as a slipper foot to join the neck to body. Panormo was well known for his innovation of extending the fingerboard over the sound hole. The majority of his guitars utilized the pin bridge commonly found on steel string guitars today, most commonly made from ebony. His guitars also used the raw materials of the modern Spanish classical guitar. Panormo used spruce tops, rosewood sides, and a spruce back covered with a rosewood veneer. He uses a fan bracing style similar to Torres but only uses five symmetrical fan braces. Panormo also does not use any of the four diagonally placed braces, on either side of the sound hole along the lower bout, in Torres’s configuration. One Panormo guitar owned by collector John Roberts had an overall string length of 62.9 cm and a body length of 44.8 cm. The width of this instrument is 22.9 cm at the upper bout, 17.5 cm at the waist, and 28.7 cm at the lower bout. [9]
Johann Georg Staufer (1778 – 1853) opened his shop in Vienna in 1800 and was known for modifications to the neck, head, and fingerboard. His “Legnani” model, named after Italian virtuoso Luigi Legnani, featured many of his innovations. The tuners were all on one side of the guitar similar to configuration on many modern electric guitars, however the gears are actually concealed within a hollowed portion of the guitars head. He also joined the neck to the body using a pivot which allowed the neck angle to be changed using a key on the instruments heel. Staufer has been credited with inventing the “flying fingerboard”. This term refers to a fingerboard that continues to the instruments sound hole without actually being joined to the body. His instruments had an overall scale length of 63 cm with a body length of 43.5 cm. The body had a width of 21.5 cm at the upper bout, 16.6cm at the waist, and 28.5cm at the lower bout. [10]
Rene Lacote (1785- after 1868) learned his craft from master luthier Joseph Pons. Innovations accredited to Lacote include struts, butterfly tuning pegs, tuners that could be operated with one hand.[11] [12] One example of a Lacote guitar owned by the Paris Conservatory has an overall scale length of 62.5 cm, an upper bout measuring 22.3 cm, a 16.5 cm waist, and a lower bout of 29.8 cm. This particular instrument has a body measuring 45 cm. [13]
Many changes to the guitar have been attributed to Antonio Torres including an increase in the width of the guitar neck. According to Harvey Turnbull in his book, The Guitar, “Since the time of Torres it has also become standard practice to make the fingerboard (width) at least 5 cm.” [14] A fingerboard that is too narrow can greatly restrict left hand movements and make intricate passages more difficult to execute, especially for guitarist with larger hands. While arguably adaptations such as this one improved his guitars, for the sake of brevity only changes affecting the acoustical capabilities of the instrument will be examined. [15]
Torres has been credited with increasing the overall size of the instrument, establishing the modern proportions of the guitar, and popularizing a revolutionary fan bracing which was commonly being used in the guitars built by luthiers near Spain’s southern peninsula especially in cities of Seville and Cádiz. [16] The most immediately noticeable difference between a Torres and guitars of his predecessors would be overall body size. In guitars pre-Torres the upper bout of a guitar ranged from 19 cm to 30 cm with an average of roughly 22 cm, the waist of the guitar averaged around 17 cm, and the lower bout averaged about 30 cm. In the guitar designed by Torres the average upper bout is about 26 centimeters, the average waist size is around 22 centimeters, and the average lower bout has been increased to around 35 cm. [17] Overall these enlargements increased both the soundboard and back of the guitar by roughly twenty percent.
Luthier Upper Bout Waist Lower Bout Overall Scale Length Body Length
Panormo 22.9 17.5 28.7 62.9 44.8
Stauffer 21.5 16.6 28.5 63 43.5
Lacote 21.5 16.6 28.5 63 43.5
Torres 26.1 22.2 34 65 46
Figure 4 Proportions established by Antonio Torres
The increased proportion of the waist produces a guitar with a drastically different look than its predecessors. The diagram to the left illustrates the proportions established by Torres. While the exact measurements differ from instrument to instrument the proportions remain consistent. The diagram displays the [18]distances between points as percentages of the instruments overall body length. The most significant increases are in the waist and lower bout. In the examples listed in the table above, the Torres model has a waist of 22.2 cm which is 48.2 percent of the overall body length of 46 cm. Conversely, the Panormo has a waist only 39 percent the length of the guitar. The Staufer and Lacote examples both have waists 38.2 percent of their body length. A significant increase in the size of the lower bout can also be seen. The Torres example has a lower bout 73.9 percent as wide as the length of the instruments body. On both the Lacote and Staufer examples the lower bout is 65.5 percent the size of the overall body length. The Panormo has a slightly smaller ratio at 64 percent.
In order to activate the entirety of the increased surface area Torres had to reduce the acoustic impedance of the soundboard by making it thinner. This thinner piece of wood was much easier to set in motion and to effectively carry vibration. Dr. Ulrike Wegst explains, “The properties on which the acoustical performance of a material depends are primarily its density, Young’s modulus, and loss coefficient. They determine the speed of sound within the material, the Eigen frequencies of a wooden bar, and the intensity of the radiated sound.” [19] In mathematical terms the speed of sound through a particular medium can be quantified with the following equation; C = the square of E divided by P wherein the speed of sound within a material c is equal to the square root of Young’s modulus (the elasticity of a material determined by a ratio of force applied measured against the proportional deformation of the material) E, divided by the materials density P. One can easily see that by lowering the denominator of the fraction in this equation (density) results in a higher speed of sound through the material. In simple terms by abating the thickness, Torres decreased the amount of wood per square inch allowing vibration to more freely traverse the soundboard.
Figure 5 Torres fan bracing pattern
To keep the new thinner soundboard from sounding “flabby” or distorted, help carry vibration all way to the edge of the larger soundboard, and maintain the quality of the higher pitched notes Torres devised a bracing system consisting of seven symmetrical struts. Torres also made his struts lighter, again reducing their overall density to maximize their sonic capabilities. The middle of these seven struts ran down the middle seam of the sound board through the lower bout. The remaining braces in this fan shape run more parallel than perpendicular to the wood grain in the sound board. Acoustician J.L. Lastinger explains the advantage thusly, “Absorption (of acoustic-impedance) is greatest for sound propagated parallel with or at a 45 degree angle to the grain of the wood, and least for perpendicular propagation; the sound speed is greatest parallel with the grain and least at 90 degrees.” [20]
Figure 6 Vibrational pattern of bracing configurations
As previously discussed vibration travels more readily when oriented parallel to woodgrain than it does against the woodgrain. By placing this lighter, less dense bracing parallel to the grain Torres was exploiting of the natural physical properties of the wood. [21] In this test conducted by, the grains of sand correlate to the vibrational patterns within the wood. The left most represents a Torres style seven strut guitar, the second a Panormo style brace configuration, the third set of pictures show a three strut fan bracing. The fourth set illustrates a ladder bracing system representative of bracing often found in early Lacote instruments. One can see dark areas extending all the way to the outer reaches of the soundboard in the seven strut configuration. While the test illustrates the weakened amplitude of the five strut system indicated by testing medium (sand) being spread evenly across the soundboard without any noticeable areas of concentration. This decreased amplitude can be corroborated by fig. 7.[22]
Figure 7 Amplitude of 3, 5, and 7 brace configurations
While the three brace pattern does produce the most amplitude the relatively small area set into motion results in inferior tonal quality. [23] Both the three brace and ladder brace systems have clear areas of concentrated vibrations activity, one can see the absence of activity near the bridge. Only the seven brace system provided the desired balance between timbre quality and increased volume.
In the later years of Lacote’s career varied this in an effort to increase the bass frequencies. Lacote was able to achieve pleasing balance by angling one of the braces resulting in greater separation between them near the bass side of the guitar. This effectively creates an area of less surface tension in this space where the gap between braces has been increased helping the guitar to put forth punchier, more audible bass notes. [24] The quality of instrument Lacote was able to build with this bracing pattern is impressive indeed because his braces went against the natural vibrational patterns of the soundboards wood grain. Before the innovations of Antonio Torres the guitars of Rene Lacote were considered to be among the finest instruments available to guitarists. Lacote was unabashedly praised by guitar virtuoso Fernando Sor in his “Methode pour la Guitare” Although the Ladote instrument had an excellent tone quality, it was still unable to achieve the dynamic range of a guitar produced by Torres.
Figure 8 Rene Lacote guitar with a slanted brace
Torres had increased the overall dynamic range of the guitar by increasing the size of the back and soundboard. However he had reversed the tonal issue that plagued most of the guitar builders before him. Instead of being too bright and thin sounding the enlarged soundboard produced notes overly saturated with bass frequencies. Tom and Mary Evans write in their book, Guitars Music, History, Construction and Players, “The real problem lies in getting a clear treble… since bass resonance tends to increase with the instruments size.” [25] This new bracing system was specifically designed to keep the new larger soundboard taut in order to clearly project the notes in the instruments higher registers.
Figure 9 Heel and foot w/ channels for sides (26)
The increased size of the guitar in conjunction with the exploitation of techniques of the aforementioned luthiers allowed Torres to deliver his tour de force. One innovations known to increase acoustic functionality present on the guitars of Antonio Torres is the use foot or shoe. The term foot refers to the section of the heel that hangs over into the guitar. On the Torres (and Panormo as mentioned previously) the heel contain a slit on both sides in which the sides of the guitar are slid into place. The foot portion of the heel extends into the body of the instrument and ultimately contacts the back of the finished instrument. This innovation allows for greater coupling of the neck, back, and sides of the guitar. Before this time the primary point of contact for the guitar neck was only a small piece of wood, similar to the small wooden patch which join the seams at the bottom of the lower bout.
Figure 10 The sides being slid into the channel in the heel/boot (27)
The significance of Torres innovations cannot be overstated. Torres had effectively solved the two of the major issues of the classical guitar. The larger size of his instrument allowed for greater volume and more resonant bass frequencies to be produced within the bodies cavity. This allowed the guitar the opportunity to be a concert instrument. No longer was guitar reduced to a mere parlor instrument as it had been known throughout the Biedermeier period and eras prior. Finally, the guitar had evolved to a point where it could fill a concert hall with robust tone and volume fitting of a “serious” concert instrument. The popularity of the guitar in the twentieth-century would be hard to imagine if not for the work of Antonio Torres.
Sources used in this blog entry:
[1] Ulrike G. K. Wegst, "Wood for Sound," American Journal of Botany 93, no. 10 (October 01, 2006): 1445, accessed November 05, 2015, http://www.jstor.org/stable/10.2307/4123127?ref=search-gateway:6f4602b01aa670824ff72d14d96f67c5.
[2] Joe Wolfe, "Guitar Construction," Guitar Construction, section goes here, accessed November 05, 2015, http://newt.phys.unsw.edu.au/music/guitaracoustics/construction.html.
[3] Wolfe
[4] Ulrike G. K. Wegst, "Wood for Sound," American Journal of Botany 93, no. 10 (October 01, 2006): 1445, accessed November 05, 2015, http://www.jstor.org/stable/10.2307/4123127?ref=search-gateway:6f4602b01aa670824ff72d14d96f67c5.
[5] Wolf
[6] Wolfe
[7] Alexander Bellow, "Chapter 8: The Nineteenth Century," in “The Illustrated History of the Guitar (New York: Colombo Publications, 1970), 163.
[8] Tom Evans and Mary Anne. Evans, Guitars (New York & London: Paddington, 1978), 48.
[9] Evans
[10] Tom Evans and Mary Anne. Evans, Guitars (New York & London: Paddington, 1978), 48.
[11] http://www.siccas.de/shop/guitar/rene-lacote-1828/
[12] James Tyler and Paul Sparks, "Chapter 13: 1790 to Early 1800's: The Triumph of the Six-String Guitar, in “The Guitar and Its Music: From the Renaissance to the Classical Era (Oxford: Oxford University Press, 2002), 248.
[13] Tom Evans and Mary Anne. Evans, Guitars (New York & London: Paddington, 1978), 53-54.
[14] Harvey Turnbull, The Guitar pg. 77
[15] Mark French, Engineering the Guitar: Theory and Practice (New York: Springer, 2009), 63.
[16] Harvey Turnbull, “Guitar,” Grove Music Online,
[17] Tom and Mary Anne Evans, “Guitars,” 60–65.
[18] Evans
[19] Ulrike G. K. Wegst, "Wood for Sound," American Journal of Botany 93, no. 10 (October 01, 2006): pg. #, accessed November 05, 2015, http://www.jstor.org/stable/10.2307/4123127?ref=search-gateway:6f4602b01aa670824ff72d14d96f67c5.
[20] J. L. Lastinger, "Acoustic Characteristics of Woods at High Hydrostatic Pressure," The Journal of the Acoustical Society of America J. Acoust. Soc. Am. 47, no. 1B (1970): pg. #, doi:10.1121/1.1911488.
[21] Graham Wade, Traditions of the Classical Guitar (London: Calder, 1980), 135.
[22] M. D. Stanciu et al., "DIAGNOSIS OF DYNAMIC BEHAVIOR OF LIGNO-CELLULOSE COMPOSITE PLATES IN THE CONSTRUCTION OF THE CLASSICAL GUITAR," Bulletin Of The Transilvania University Of Brasov, Series I: Engineering Sciences, 1st ser., 1, no. 50 (2008): 58.
[23] M. D. Stanciu et al., "DIAGNOSIS OF DYNAMIC BEHAVIOR OF LIGNO-CELLULOSE COMPOSITE PLATES IN THE CONSTRUCTION OF THE CLASSICAL GUITAR," Bulletin Of The Transilvania University Of Brasov, Series I: Engineering Sciences, 1st ser., 1, no. 50 (2008): 57.
[24] http://www.thisisclassicalguitar.com/bracing-styles-for-classical-guitars/
[25] Tom and Mary Anne Evans, “Guitars,” 81.
[26] John S. Bogdanovich, Classical Guitar Making: A Modern Approach to Traditional Design (New York: Sterling Pub., 2007), 218.
[27] Bogdanovich