Guitar Strings from the 18th Century to the Advent of Nylon (Part 2)

Types, Manufacturing Techniques, and Selection Criteria

by Mimmo Peruffo

In this second part, we examine the criteria used to select string setups for our instrument during the 18th century, drawing on the scarce surviving documents from that period.

Guitar String Types

The 18th Century
At that time, the guitar typically featured four double strings (the so-called “choirs,” though we prefer to call them “courses”) plus a chanterelle, which was usually, but not always, single, with frets made from segments of gut string. The tuning—most commonly in E, though occasionally in D—was known to vary, particularly for the two lowest courses, which could be tuned either an octave apart or in unison. The range of vibrating lengths for this instrument was significantly greater—between 69 and 74 cm—compared to the 62–63 cm typical of guitars from Sor’s era.
Why these specific measurements and not others?
To fully understand this, we must first consider the behavior of strings in that period, when gut was essentially the only material available. In other words, it is somewhat akin to a modern scenario in which we had only nylon strings—albeit in various necessary thicknesses—and were tasked with ensuring acceptable acoustic performance across all registers of a guitar (or lute). When a string of any material is progressively stretched between two fixed points (its vibrating length), it reaches a frequency at which it breaks, having attained its breaking load. For gut, this averages around 34 kg/mm², ⁴³ a value that can be considered valid—for several well-established reasons—for strings made in the 18th and 19th centuries as well. In short, the strings of that time had roughly the same tensile strength as ours today. This critical frequency, known as the “breaking frequency,” is entirely independent of diameter, a fact that can be easily verified mathematically (using the general string formula) or experimentally.
This threshold frequency is inversely proportional to the vibrating length of the string: halve the vibrating length, and the frequency doubles; double it, and the frequency halves. Put differently, the product of the vibrating length (in meters) and the breaking frequency (in Hz) is a constant termed the “breaking index.”
The experimental breaking index of a modern gut string ranges between 220 and 290 Hz · m, averaging approximately 260 Hz · m, corresponding to the aforementioned breaking load of 34 kg/mm². ⁴⁴ This implies that, at a vibrating length of one meter, a string would theoretically snap at 260 Hz.
By dividing the breaking index by the desired pitch frequency of the top string (the luthier’s starting point), one obtains the vibrating length at which the string would break for that pitch. For instance, consider the chanterelle of a Baroque guitar tuned to a hypothetical 17th-century pitch standard of 415 Hz—where E = 311 Hz. The theoretical breaking length would then be 83 cm (260 ÷ 311).
However, the practical working vibrating length must prudently be shorter than this limit. But by how much? To address this question, let us briefly digress.
As previously noted, musicians of the 16th and 17th centuries who played plucked (or bowed) instruments took care to ensure that the strings of an instrument felt neither excessively taut nor overly slack, a sensation that should remain consistent across the entire setup. This is precisely what we would do today if pre-made string sets were unavailable, and we had only loose strings of various gauges to choose from. The pursuit of an appropriate and subjective degree of tension naturally entails selecting the most suitable diameters.
There is a second factor to consider—one that perpetually troubled musicians and luthiers before the advent of wound bass strings: as the diameter of a gut string increases—under equal tension and vibrating length—it produces progressively lower pitches (since diameter and frequency are inversely proportional), but its overall acoustic performance, in terms of dynamics, harmonic richness, and sustain, diminishes increasingly. Beyond certain gauges, the sound becomes utterly unsatisfactory. Essentially, as their rigidity increases due to larger diameters, strings become progressively more damped and muted. This can be readily observed today on a modern guitar by comparing the acoustic properties of the G string to those of the high E. A D or A string in pure nylon, rather than wound, would measure approximately 1.4 mm and 1.9 mm respectively—imagine the sonic chaos that would ensue. Worse still, strings of such thickness, when fretted, exhibit greater pitch increases than thinner ones; slight variations in finger pressure on the frets result in significant frequency shifts. This occurs because thick strings made from a single material (e.g., pure nylon) are inherently extremely rigid.
Thus, to best preserve the performance of fretted bass registers while limited to gut (metal strings existed, of course, but their entirely different timbre and the design constraints they imposed were significant), the only viable path for luthiers of the time was to maximize the vibrating length. Only by pursuing this approach (since vibrating length and diameter are inversely proportional) could they hope to minimize string diameters and extract optimal sound quality. However, this length was constrained by the tensile limits of the chanterelle, as outlined earlier.
This elucidates, in reverse, a rule from the 16th and 17th centuries for lutes, guitars, and similar instruments—one that is poorly understood today: tune the top string to the highest pitch it can sustain. Adhering to this condition was the only way to achieve—at equal tension—the maximum reduction in string diameters, thereby fully unlocking the sound’s dynamic and timbral components. It becomes readily apparent that the vibrating lengths, calculated by luthiers based on the mechanical and acoustic properties of the strings available to them, confined the chanterelle’s frequency—even if empirically tuned by the lutenist—to a narrow range. Tuning too high risked immediate breakage; tuning too low compromised acoustic quality for that given vibrating length. A vibrating length of 59 cm, typical of certain historical lutes such as Vendelio Venere’s seven-course model, ⁴⁵ was calculated to achieve a potential G tuning at the late-16th-century Venetian pitch standard, approximately a semitone sharper than our modern 440 Hz, suggesting that luthiers of the time were well aware of the breaking index concept. ⁴⁶ The same reasoning applies to 18th-century German lutes with 11 or 13 courses tuned in D minor: knowing with certainty that the top note was an F at “Kammerton,” ⁴⁷—roughly a full step below our modern standard ⁴⁸—and given the typical vibrating length range of these instruments (68–72 cm), it is clear that the chanterelle operated near its breaking frequency. Based on these considerations—extendable also to the viol family, at least until the second half of the 17th century—researchers have long calculated that the working vibrating length required a cautious reduction of approximately 2–3 semitones below the breaking length, yielding a working index of 230–240 Hz · m. ⁴⁹ This value is also derived from the lute in Table XVI, no. 3 of Michael Praetorius’s Syntagma Musicum (“Sciagraphia,” Elias Holwein, Wolfenbüttel, 1615–1620), where the product of the measurable vibrating length (determinable because the author specifies the unit of measure) and the assumed chanterelle frequency equals 235 Hz · m.
This theory finds strong experimental support when observing the behavior of a whole gut chanterelle (as they were made at the time) with a progressive increase in pitch frequency: approximately 2–3 semitones before breaking, it markedly loses its ability to stretch, behaving almost like a steel wire. ⁵⁰ In practice, as tension increases, the string’s frequency rises far more rapidly than expected, even with minimal peg adjustments, until it soon snaps.

This undoubtedly served as an excellent cue for the lutenists and guitarists of the time, as well as for those—such as luthiers—who needed to skillfully dimension a guitar, lute, or viol. In other words, the string itself automatically signaled to the player when its limit was reached, thereby guiding the luthier in correctly proportioning an instrument based solely on the chanterelle’s pitch (with the other strings following proportionally), as dictated by the local pitch standard specified by the client. It is well known that not all E’s, G’s, etc., across various European regions were identical, varying by as much as 2–3 semitones from state to state—a factor that luthiers had to duly account for. This explains why a hypothetical G-tuned archlute built by Matteo Sellas in Venice in 1640 has a fretted vibrating length of only 58 cm, while a similar instrument crafted by Bassiano Haim in Rome in 1668 boasts a fretted vibrating length of 64.5 cm.
The difference between these two vibrating lengths equates to approximately two semitones, aligning precisely with what is believed to have been the frequency disparity between the Venetian and Roman pitch standards of the 17th century.
Whether the instrument was destined to take an “8” shape, like the guitar or vihuela de mano, or a “pear” shape, like the lute, or whether it was played by plucking or bowing, did not alter this fundamental principle. This is why constructing exact replicas of original 16th- and early 17th-century instruments—particularly viols and Renaissance lutes—poses an frankly intractable dilemma: assuming all parts are in their original condition, for which pitch standard were they designed? It is not uncommon today to encounter exact replicas of G-tuned lutes (i.e., “Mezano,” now called “Tenor”) with vibrating lengths of 65 cm, or even archlutes with 68 cm, intended to be tuned to G at our modern pitch of 440 Hz. A simple calculation of the product of the modern G frequency (392 Hz) and the vibrating length would immediately reveal to anyone that the working index would exceed the limits of gut, and that fitting a thinner chanterelle in hopes of avoiding breakage would be futile. In practice, a modern G-tuned lute strung with gut should never exceed a vibrating length of 61–62 cm.
Based on these considerations, the breaking length previously indicated for the guitar—82 cm—corresponds to a working length of 69–73 cm, which, coincidentally, is a typical range for five-course instruments from the 17th and early 18th centuries that have survived. Tuning the chanterelle to E (A=415 Hz) places it 2–3 semitones below its hypothetical breaking point. The original purpose of octave pairings for the bass strings in the 16th century likely aimed to compensate, through this ingenious device, for the upper harmonics severely compromised in thicker strings (as noted by Sebastian Virdung in Musica getutsch…, Basel, 1511), and curiously persisted even after the invention of wound strings.
Italy

The Stradivari Museum in Cremona houses numerous drawings and templates made of paper or cardboard pertaining to plucked and bowed musical instruments. One of these (drawing no. 375) is of particular interest (see Fig. 2) as it records the description of the strings required for the five fretted courses of the “theorboed guitar,” essentially a five-course guitar with five single bass strings in extension:
1st and 2nd strings (first course): “These must be paired, two guitar chanterelles.”

3rd and 4th strings (second course): “These must be paired, two guitar sottanelle.”

5th and 6th strings (third course): “These must be paired, two thick violin chanterelles.”

7th string (fourth course): “This other string must be a violin canto.”

8th string (fourth course): “This other string must be a guitar sottanella.”

9th string (fifth course): “This other string must be a thicker violin canto.”

10th string (fifth course): “This other string must be a violin chanterelle.” ⁵¹

Sacconi attributes these notes, dating to the first half of the 18th century, to one of Stradivari’s sons, who, though he died in 1737, was compelled to delegate much of his work to assistants after 1725. ⁵²
Let us attempt to estimate the diameters involved. As will be seen with the guitar of the following century, this represents the earliest chronological reference to contemporary violin gauges. Through Count Riccati—a distinguished physicist and amateur violinist friend of Tartini—we know with certainty that the terms “cantino” and “canto” refer to the violin’s E and A strings, respectively. ⁵³ Based on Riccati’s measurements around 1740–50 on his violin strings, we know that the cantino and canto measured approximately 0.70 mm and 0.90 mm, respectively. ⁵⁴ These estimates are indirectly corroborated by data provided by the French traveler and astronomer De Lalande around 1760, ⁵⁵ regarding the number of guts used to produce strings for mandolin, violin, and double bass by the renowned Abruzzese string maker Domenico Antonio Angelucci, active in Naples. ⁵⁶ Notably, these proportions remained rigorously consistent until the end of the following century, both in Italy and France. ⁵⁷ As for the designation “thick” cantini/canti, we take as a guide the larger gauge (“thick”) values for E and A strings made from the same number of gut strands, as indicated by George Hart. ⁵⁸

Given the high standardization in the manufacturing process of violin strings, it is plausible to hypothesize that a “thick” three-strand cantino might measure around 0.73 mm (roughly the maximum diameter obtainable from three strands of 8–9-month-old lamb gut, as experimentally verified by us string makers), with a standard canto at 0.90 mm and a “slightly thick” canto at 0.95 mm.
Since the third course of this guitar utilized a violin cantino (traditionally made with three guts, or “strands,” Fig. 3), the second course, by simple mathematical proportion, must have consisted of two strands (like the chanterelle of a mandolin or pardessus de viole, per De Lalande), and the first of just one gut, exactly as with lute chanterelles. ⁵⁹ In theoretical calculations, the ratio between diameters corresponds to the square root of the ratio of the number of strands used.
The first string could only have had the same gauge as those of the nearly obsolete lute, since the guitar of the time merely adhered to the same guiding principles—namely, the pursuit of maximum vibrating length to operate with the top string near its breaking point. Given that three strands yield a diameter of approximately 0.70 mm, the diameters for the first, second, and fifth courses can be derived through simple mathematical proportions. Thus, the hypothesized diameters are as follows:
1st course: ~0.42 mm (one gut).

2nd course: ~0.57 mm (two guts).

3rd course: ~0.73 mm (thick violin cantino: three guts).

4th course: ~0.90 mm (violin canto).

4th course: ~0.57 mm (two guts).

5th course: ~0.95 mm (thicker violin canto).

5th course: ~0.70 mm (violin cantino: three guts).

As can be observed, the fourth and fifth courses consist of a fundamental bass paired with its octave, a system more typical of the early 17th-century Italian school (e.g., Benedetto Sanseverino) than of Stradivari’s French contemporaries, such as Corbetta and De Visée. The latter favored tuning the two strings of the fifth course in unison at the upper octave, while the fourth comprised the fundamental bass paired with a thinner octave string. Regarding the vibrating length of the guitar in question, template no. 374—pertaining to another guitar for which Stradivari provides various measurements—offers assistance. By comparing the data, a vibrating length of 68.3 ± 5 mm can be deduced. ⁶⁰ For the purpose of estimating working tension, the pitch standard is conventionally set at 415 Hz. The fact that the first three strings of this instrument take one, two, and three guts, respectively (exactly as with the lute), suggests an intriguing hypothesis: the fourth intervals between the strings of lutes, guitars, and other plucked instruments may not have been dictated by musical, philosophical, or merely ergonomic considerations (e.g., optimal finger placement on the fretboard), but rather by the more prosaic fact that only these intervals allowed strings made of one, two, and three guts (and so forth) to achieve a consistent tactile sensation of stiffness.
As the number of paired guts increases, the difference in diameter between adjacent strings (e.g., between a string made of ten guts and one of eleven) naturally decreases; conversely, the gauge disparity among strings made of fewer guts is quite significant.
Here, then, are the working tension values for each individual string; these should be considered doubled (or summed in the case of the 4th and 5th courses) since the two strings of a course behave tactilely as if they were a single string:
1st course: ~3.3 kg per string (6.6 kg total if doubled).

2nd course: ~3.3 kg per string (6.6 kg total).

3rd course: ~3.5 kg per string (7.0 kg total).

4th course octave: ~4.6 kg.

4th course bass: ~3.0 kg.

5th course bass: ~1.87 kg [!].

5th course octave: ~4.0 kg.

The tension value for the bass of the fifth course is notably lower than the average, while the remaining values maintain roughly the same tension, except for the two octaves. Stradivari’s indications allow us to observe that the string of the second course was also used to create the octave paired with the bass of the fourth. A slightly thinner gauge than that of the third course, meanwhile, produced the octave paired with the fifth. The most plausible explanation for the reduced working tension of the bass string lies in the likelihood that this gauge indicates the size of the core intended for subsequent metal winding. There are similar examples regarding the fourth string (the only wound string) of the violin, drawn from contemporary string gauges (Fig. 4). ⁶¹

Unfortunately, we have no further information from Italy.
France

Le Cocq, in 1729, provided valuable insights into selecting strings for the guitar of his time. ⁶² After specifying that all strings were made of gut, explaining how to distinguish a good string from a false one (Fig. 5), and discussing frets, Le Cocq notes that the second and third courses, as well as the octave of the fourth, used strings of similar thickness. In essence, if understood correctly, a single gauge covered three courses: “All other ranks or strings [beyond the single chanterelle] can be of the same thickness…” The octave of the fifth course bass, or bourdon, was to be imperceptibly thicker than the strings of the third course. The basses of the 4th and 5th courses were wound, employing a core as thick as their paired octaves, loaded with a thin brass or, preferably, silver wire “…which loads them only halfway: that is, leaving an empty space on the string equal to the thickness of said wire or even slightly more…”
Notably, the winding was not tightly coiled, as with strings generally available in French shops—“entirely wound or too thick”—but rather of the “demi” type, with coils spaced approximately the diameter of the wire or slightly more, and “made at home.” In this way, Le Cocq explains (convinced he was unique in this practice in his country), the sound is less dry and harsh than that produced by common tightly wound strings available on the market, which he also deemed too thick. Here, too, the presence of fundamental basses in the fourth and fifth courses should be noted, partially diverging from the criteria adopted by De Visée and Corbetta. A fine iconographic example where the fourth and fifth strings of a five-course guitar appear white (thus presumably wound with silver or silvered copper) is a painting by Jean Baptiste Oudry (1686–1755): Allegorie der Künste, 1713 (Schwerin, Staatliches Museum). Despite this information, no comparisons with the gauges of other instruments are provided, making it impossible to hypothesize string diameters.
Michel Corrette, 1761: “The guitar is strung with five courses; the 1st has only one string, called the chanterelle, and the other four courses each have two… It must be observed that the two strings of the 3rd course and the small octave string of the 5th course should be equal in thickness, not as thick as a violin chanterelle. The two strings of the 2nd course are equal and thinner than the former. The chanterelle and the smaller string of the 4th course are equal in thickness and thinner than those of the 2nd course. The 1st string of the 4th course is half-wound, thicker than that of the 3rd course. The 1st of the 5th course is fully wound, thicker than the 4th. Silk strings can be wound in the Chinese manner, which use no others for their stringed instruments, making the sound more pleasant and resonant…” ⁶³
Observations: The reference points are the third course and the octave of the fifth, which share a gauge equivalent to the contemporary violin cantino, around 0.70 mm (three strands of 8–9-month-old lamb gut). It thus becomes evident that the second course and the chanterelle could only take two and one gut, respectively, in line with the diameters of the first three courses and the considerations made for Stradivari’s “theorboed guitar.” Unlike the Italian luthier, however, the octave paired with the fourth course matches the chanterelle’s diameter (whereas with Stradivari it matched the second course), while the fifth course’s octave uses the third course’s gauge, somewhat akin to Stradivari’s renowned “theorboed guitar.” Particularly noteworthy is the suggestion to use twisted silk cores (like a cord) as an alternative to the usual gut cores for winding—a practical indication from the 18th century that is the first to propose silk as a core for wound strings.
Here are the presumed diameters:
1st course: (~0.42 mm: one gut).

2nd course: (~0.57 mm: two guts).

3rd course: ~0.70 mm (average violin cantino: three guts).

4th course bass: ?

4th course octave: ~0.42 mm (= chanterelle: one gut).

5th course bass: ?

5th course octave: ~0.70 mm (violin cantino: three guts).
Considering a vibrating length typical of a French guitar—such as an instrument by Alexandre Voboam from 1676 (Paris, Conservatoire, E 1532) at 69.4 cm—the tension values can be deduced (for a French pitch standard around 390 Hz):

1st course: ~3.0 kg per string (6.0 kg total if doubled).

2nd course: ~3.1 kg per string (6.2 kg total).

3rd course: ~3.0 kg per string (6.0 kg total).

4th course octave: ~2.4 kg.

4th course bass: ?

5th course bass: ?

5th course octave: ~3.8 kg.

A certain discrepancy is observed between the tensions of the octaves paired with the basses of the 4th and 5th courses, while the upper courses exhibit values comparable to the Italian example.
P. J. Baillon, 1781: “The guitar should be strung to the standard pitch of an orchestra. Care must be taken that the strings are well chosen and uniform. The best method is to string it with double strings; only the chanterelle should be single: the second strings must be thicker than the chanterelle and tuned in unison; the third strings must be thicker than the second and likewise tuned in unison; the fourth must be fully wound silk, accompanied by a gut string slightly thicker than the chanterelle and tuned to the octave of the wound string; the fifth must also be fully wound silk, thicker than the fourth, and accompanied by a gut string slightly thicker than the second strings and tuned to the octave of the wound string. It must be observed that the strings accompanying the fourth and fifth should be placed after the wound strings, that is, they should be the first on the thumb side.” ⁶⁴
Observations: Regarding the first three courses, no specific indications are given beyond the clarification that the chanterelle is single. More interesting is what is noted for the octaves of the fourth and fifth courses: they were to be slightly thicker than the chanterelle and second course strings, respectively, rather than the second and third as with Stradivari. As for the basses, the sole recurring indication here is to wind them on silk. ⁶⁵ A further observation regarding the bass octaves: for the fourth course, there is substantial alignment with Corrette’s criteria, namely the use of a chanterelle string—albeit slightly thicker—for the paired octave. As with Le Cocq, it is unfortunately impossible to deduce any string diameters.
One final piece of information from a French source, taken from the Encyclopédie Méthodique, states: “Wound bourdons have two drawbacks: one is that they wear and cut the frets; the other, more significant, is that they overly dominate the other strings, causing their final sound to be lost due to the duration of their own, especially in strumming. There are chords where they may work well, namely when they produce the fundamental note; but since this is not usually the case, it is better to stick to simple bourdons unless one intends only to pluck. Visée, a renowned guitar master under Louis XIV, used none on the fifth course; but he thereby lost the octave of A, and consequently a half-octave.” ⁶⁶
The wear of gut frets caused by wound basses may have been the decisive factor prompting the transition to ivory or metal frets; however, this shifted the wear issue to the wound strings themselves—a problem that persists even today.
Mexico
It may seem surprising that information about the guitar should come from one of Spain’s American colonies, especially since, as with other instruments, little of significance has thus far been found overseas. The treatise by Antonio Vargas y Guzman (1776) merits particular attention as it specifies the strings to be used for the six-course guitar, an instrument popular in Spain from the late 18th century into the early decades of the 19th century. ⁶⁷
Vargas specifies that the guitar has six courses: the first three in unison, while the wound basses (termed entorchados) are typically tuned in octaves. He further notes that if the guitar is used for accompaniment—especially in a “large” orchestral ensemble—the basses should also be in unison. Unfortunately, no additional details are provided.
In the treatise, the strings of the third course match the gauge of the violin’s second string (thus ~0.90 mm), and the second course matches that of the violin’s cantino, averaging ~0.70 mm.
We can now establish a hypothetical vibrating length of 66 cm, such as that of the guitar by Sanguiño of Seville (1759), which indeed has six or seven courses. ⁶⁸ As for the pitch standard, the possibilities are broad since we lack concrete evidence; however, if we speculatively adopt 415 Hz, we can estimate the working tension for the second and third courses:
B: ~0.70 mm: ~4.8 kg.

G: ~0.90 mm: ~5.0 kg.

The most significant finding is that between these two courses (and likely the subsequent ones as well), a condition approaching equal working tension emerges, consistent with the cases previously examined.
It follows that the chanterelle likely also bore ~5.0 kg of tension, resulting in a diameter of approximately 0.53 mm—roughly what is obtained with two gut strands, as used for the mandolin or pardessus de viole chanterelle. ⁶⁹
With these documents, our knowledge of the guitar in the Age of Enlightenment concludes. As highlighted by the scant data recovered, a profile of equal tension among the strings seems to emerge.
From the 17th century, however, we currently possess nothing significant beyond a few workshop inventories listing expenses for the purchase of various strings, including those for guitar. Nevertheless, it can be asserted that the guitar did not benefit—at least until the second half of the 17th century—from wound basses.
Given the close design kinship (e.g., the criteria for selecting vibrating length in relation to the top string’s pitch), it is believed that the gauges used in the 17th-century guitar were none other than those commonly employed in the lute.
Regarding the provenance of guitar strings, it is worth noting—as with the violin—the French preference for Italian products, considered unsurpassable, particularly for chanterelles, over other manufactures. For instance, Michel Corrette writes: “Good gut strings usually come from Rome, Florence, Naples, and Lyon, etc.” ⁷⁰
The preference for strings from Rome, and even more so from Naples, is also evident in the letters of the viola da gamba player Forqueray and persists unchanged, for other bowed instruments as well, at least until the end of the 19th century. ⁷¹
Concomitant with the spread of silk-wound basses in the guitar (which undeniably offer superior acoustic performance compared to those wound on gut), the rule of seeking the maximum vibrating length, adhered to even in the first half of the 18th century, lost its technical justification. This enabled late 18th-century luthiers to significantly shorten the vibrating length (by about a tone) in our instrument as well, enhancing ease of execution—an aspect that became particularly necessary due to evolving musical demands. This agility was further facilitated by a concurrent gradual elimination of courses in favor of single strings, the replacement of gut frets with fixed ivory or metal ones, and, finally, the pivotal addition of a sixth bass string tuned to E, which marked the end of the constantly inverted chords typical of the five-course instrument. It should be noted that a plucked instrument with single strings inherently possesses greater dynamic versatility and executive agility than one with courses. Regarding the reasons that may have inspired the addition of the sixth bass string, the influence of the six-course mandora—a highly popular instrument in Austria, Germany, Bohemia, and Moravia during the period of this significant transformation—cannot be overlooked. ⁷² This instrument exhibits strong affinities—in the number and arrangement of strings as well as in performance characteristics—to what would later become the six-string guitar: an entirely different world from the contemporary five-course guitar.
This is barring the fact that it morphologically resembled the six- to eight-course Renaissance lute. A particular discussion is warranted for the bracing, which, in the area beneath the bridge, was emblematically constructed (at least in surviving mandora examples) with five fan-shaped braces rather than the classical lute arrangement (i.e., two oblique braces on the chanterelle side and a very thin brace, slightly curved toward the staves, placed transversely across the soundboard halfway between the bridge and the bottom of the table, extending no further than the bridge section occupied by the basses).
Comparative experiments between traditional and fan-shaped bracing have revealed that the latter uniquely supports the mid and bass registers of a lute acoustically. ⁷³ The mandora typically had a D tuning but with the same intervals as the guitar. Given that the vibrating length of many museum-preserved specimens ranges between 70–72 cm, a simple proportion yields a vibrating length of 62–64 cm (coincidentally!) when theoretically adjusted for an E tuning. Such instruments were sought after beyond the Alps for their agility and the presence of sound in the bass part, posing fierce competition to the theorbo and lute. This competition was even more formidable for the five-course guitar, which no longer enjoyed its 17th-century distinction of being played with strumming—a feature that somehow set it apart from other plucked instruments—and thus found itself in dire need of adaptation to counter it. Simon Molitor, in 1807, remarks on this:
“Now, the guitar has received a second improvement through the addition of the sixth string, precisely the low E, which immediately became common among us. In this way, the guitar became entirely akin to the mandora.” ⁷⁴
The reasons why the guitar shortened by approximately two frets are not explicitly clear; however, given its perennial symbiotic relationship with the violin, it seems plausible that only this precise shortening allowed the direct use of the violin’s first three strings while ensuring a tension deemed appropriate. Significantly, the guitar adopted a vibrating length exactly double that of the violin, also featuring a high E chanterelle: the guitar of Sor and Giuliani’s era was born.

43. A section of 1 mm² corresponds to a string of approximately 1.13 mm in diameter
44. DJILDA ABBOT – EPHRAIM SEGERMAN, Strings in the 16th and 17th centuries, “The Galpin Society Journal”, XXVII 1974, pp. 48-73. Based on our experiments, the average breaking load value for gut indicated by Segerman (32 kg/mm²) appears too low
45. “Vendelio Venere in Venetia 1596”, seven-course lute, Bologna, Accademia Filarmonica. Other valid examples of Venetian lutes in museums include: “Giovane Hieber in Venetia”, second half of the 16th century, vibrating length 59 cm, Brussels, Musée Royal Instrumental, no. 1561; “Matteo Sellas in Venetia, 1638”, 14-course theorboed lute, vibrating length 58 cm, Paris, Musée de la Musique, no. 1028.
46. ARTHUR MENDEL, Pitch in Western Music since 1500: A Re-examination, “Acta Musicologia”, L, 1978, pp. 1-93.
47. Cf. ERNST GOTTLIEB BARON, Historisch-theoretisch und practische Untersuchung des Instruments der Lauten, Johan Friedrich Rüdiger, Nürnberg 1727, translated by Douglas Alton Smith, Instrumenta Antiqua Publications, Redondo Beach (Cal.) 1976, p. 98.
48. EPHRAIM SEGERMAN, On German, Italian and French Pitch Standards in the 17th and 18th Centuries, “FOMRHI Quarterly”, no. 30, January 1983, comm. 442.
49. R. THOMAS WILLIAM & J. J.K. RHODES, The String Scales of Italian Keyboard Instruments, “The Galpin Society Journal”, XX, 1967, p. 48.
50. DANIELLO BARTOLI, Del Suono, de’ Tremori Armonici e dell’Udito, Treatise by Fr. Daniello Bartoli of the Society of Jesus, Rome 1679. At the expense of Nicolò Angelo Tinassi. 4to, 8 + 330 + 1 pp.; Property of Roberto Regazzi, Bologna; ‘Chapter Five’, “Digression. Whether strings are equally taut throughout their length: and for what reason they break when overstretched.” Bartoli states on p. 263: “A string [from a lute, ed.] tears when it can no longer stretch: that is, as long as it can stretch, it cannot tear: and this seems to me as true as the fact that, in natural and necessary operations, one does not reach the extreme without first passing through all intermediate stages and overcoming their resistances, which are always lesser. But tearing is the extreme of stretching, therefore it does not occur as long as the string, by stretching, can avoid tearing.”
51. PATRIZIA FRISOLI, The Museo Stradivariano in Cremona, “The Galpin Society Journal”, XXIV, July 1971, p. 40.
52. S. SACCONI, I Segreti di Stradivari, Cremona, 1972. Full name and publisher missing
53. PATRIZIO BARBIERI, Giordano Riccati on the Diameters of Strings and Pipes, “The Galpin Society Journal”, XXXVIII, 1985, pp. 20-34: “With gold scales I weighed three equally long portions, one Venetian foot, of the three violin strings called the tenor, the canto, and the cantino. I refrained from investigating the weight of the thickest string, as it is not made solely of gut like the others, but is usually wound with a thin copper wire.”
54. PATRIZIO BARBIERI, op. cit. See also: MIMMO PERUFFO, Italian Violin Strings in the Eighteenth and Nineteenth Centuries: Typologies, Manufacturing Techniques and Principles of Stringing, “Recercare”, IX, 1997, pp. 155-203.
55. FRANÇOIS DE LALANDE, Voyage en Italie […] made in the years 1765 & 1766, 2nd edition, vol. IX, Desaint, Paris 1786, pp. 514-9, Chapter XXII “On the Craft of Gut Strings…”: “…only two guts are used together for the small mandolin strings, three for the first violin string…”
56. UBERTO ANDREA, L’antico abitato di Salle…, vol. I, Casamari, Tipografia dell’Abbazia, n.d., p. 77: “Among the string makers who very often worked outside the village or kept a shop there, Carlo Antonio Ruffini, Domenico Antonio De Domicis, Domenico Antonio Angelucci, and Giosafatte Di Rocco stood out…” State Archives of Chieti, Royal Audience of Chieti fund no. 77. Cadastre of Salle, 1746.
57. FRANÇOIS DE LALANDE, op. cit., p. 174.
58. GEORGE HART, The Violin and Its Music, Dulau and Schott, London 1881, pp. 46-7.
59. ATHANASIUS KIRCHER, Musurgia Universalis sive Ars Magna Consoni et Dissoni in X. Libros Digesta, Rome, 1650, Chapter II, p. 476: “…thus here in Rome they make the lowest lute string from 9 guts, the second from 8, and so on up to the last and smallest, which consists of one gut.”
60. MARTYN HODGSON, The Stringing of a Baroque Guitar, in “FOMRHI Quarterly”, no. 41, October 1985, pp. 61-67.
61. Cf. FILIPPO FODERÀ, Metodo of 1834, cited by PATRIZIO BARBIERI in Acustica, accordatura e temperamento nell’illuminismo veneto, Istituto di Paleografia Musicale, Torre d’Orfeo, Rome, 1987, p. 42: Gauge of strings at the drawplate thicknesses Violin by Guarnerius Degree of drawplate thicknesses

chanterelle Straight 17/80 Reverse 20/100
second Straight 25/80 Reverse 28/100
third Straight 29/80 Reverse 35/100
Core – Reverse 29/100
These measurements refer to Foderà’s string gauge and pertain to both sides of it. Another illuminating example comes from the violin string gauge of LOUIS SPOHR, “Violinschule […],” Tobias Haslinger, Vienna 1832, pp. 13-14, plate 1, figure IV, where the following markings are noted: E 18, A 23, D 31, and G 25. The unit of measure is unfortunately unknown to us. The string gauge consisted of a metal plate with a sharply angled graduated notch featuring engraved marks: the string was inserted into this slot and, as it moved toward the inner vertex, it eventually—due to its thickness—touched both sides of the graduated notch, providing an approximate but effective measurement. This tool was likely in use from the early 19th century until the mid-20th century.

62. FRANÇOIS LE COCQ, Recueil des pièces de guitare composées par Mr. François Le Cocq, Brussels, Bibliothèque du Conservatoire Royal de Musique, Ms. Littera S, no. 5615, 1730. Chapter: “Des chordes”.
63. MICHEL CORRETTE, Les Dons d’Apollon, Paris 1763, p. 22, Chapter XVI.
64. P. J. BAILLON, Nouvelle Méthode de Guitarre, Paris, 1781, p. 3. “The guitar must be strung to the usual orchestral pitch. Care must be taken that the strings are well chosen and uniform. The best method is to string it with double strings; only the chanterelle must be single. The second strings must be thicker than the chanterelle and tuned in unison; the third strings thicker than the second and also in unison. The fourth must be fully wound silk and accompanied by a gut string slightly thicker than the chanterelle, tuned to the octave of the wound string. The fifth must also be fully wound silk, thicker than the fourth, and accompanied by a gut string slightly thicker than the second strings, tuned to the octave of the wound string. It must be ensured that the strings accompanying the fourth and fifth are placed after the wound strings, that is, they must be the first on the thumb side.”
65. In truth, silk-wound basses had already been described by Playford in 1664 (An Introduction to the Skill of Music […]. The Fourth Edition Much Enlarged, William Godbid for John Playford, London, 1664), when the recent invention of wound strings was officially announced to the musical world of the time; however, no historical source documents their use before the second half of the 18th century.
66. Encyclopédie Méthodique, Paris, 1785, Chapter: L’art du faiseur d’instruments de musique. “Wound bourdons have two drawbacks: one is that they wear and cut the frets; the other, more significant, is that they dominate the other strings too much, causing their final sound to be lost due to the duration of their own, especially in strumming. There are chords where they may work well, namely when they produce the fundamental note; but since this is not often the case, it is better to stick to simple bourdons unless one intends only to pluck. Visée, a renowned guitar master during Louis XIV’s reign, used none on the fifth course, thereby losing the octave of A and, consequently, a half-octave.”
67. ROBERT STEVENSON, A Neglected Mexican Guitar Manual of 1776, “Inter-American Music Review”, 1, 1979, pp. 205-10: “Explanation for Playing the Guitar by Plucking with Music or Cipher and Useful Rules for Accompanying the Bass Part, Divided into Two Treatises by D. Juan Antonio Vargas y Guzman. Professor of this Instrument in the City of Veracruz, Year 1776”, Newberry Library, Chicago, Case MS VMT 582 V29e; p. 291.
68. As suggested in 1999 by Dr. Paul Sparks in a private communication to the author
69. FRANÇOIS DE LALANDE, op. cit., p. 174.
70. MICHEL CORRETTE, op. cit., p. 22. “Good gut strings usually come from Rome, Florence, Naples, and Lyon.”
71. See Forqueray’s letter to Prince Wilhelm, late 1767–early 1768: “…that the last two small strings be Roman, the last five from Naples…” Cited by YVES GÉRARD in Notes sur la fabrication de la viole de gambe et la manière d’en jouer, d’après une correspondance inédite de J.B. Forqueray au prince Frédéric-Guillaume de Prusse, Recherches sur la musique française classique, II 1961-2, letter 7: “To His Royal Highness Monseigneur the Prince of Prussia”.
72. PIETRO PROSSER, Calichon e Mandora, ovvero: das non plus ultra satis est, “il Fronimo”, no. 109, Part I, April 2000, pp. 44-52.
73. GEOFF MATHER, Enigmatic Bars and Below the Bridge Bars (Some Observations), “FOMRHI Quarterly”, Bulletin 23, April 1981, comm. 334, p. 47.
74. PIETRO PROSSER, Calichon e Mandora, ovvero: das non plus ultra satis est, “il Fronimo”, no. 110, Part II, July 2000, p. 33, footnote 56.