Peculiarities of beef gut

Nowadays, most of the professional stringmakers use beef gut instead of sheep gut. From an historical point of view, the early use of this material dates back to the half of the xviii century but so far we have no evidence of a musical use of it. The industrial production of “serosa” type strings is made possible by machines called “slitting machines” that cut the intestines transforming them into stripes.

Further explanations on the video below:

https://www.youtube.com/watch?v=VuToV06CsdEhttp://

Essentially, the portion of intestine usually called “runner” which has a diameter of 40 to 50 millimetres and a length of 40 to 45 metres is to be cut in two or three longitudinal stripes starting from the fatless part, meanwhile the remains (around three quarters of all the material) constitute the waste and will serve other purposes.

Sheep gut can instead be kept unsplit or be cut in the middle. The result of the second process consists in two stripes called “beef serosa” which are indeed a kind of “sandwich” made of two membranes: the first one is called layer 1, it has a longitudinal configuration and, consequentially, it is more resistant, the second, and weaker, one is called layer 2 and its fibres are in a diagonal order.

Because of the different shape and consistency of the two layers, their separation becomes necessary and it can be carried out by human personnel or by a specialised Machine. The presence of layer 2 in layer 1 stripes is the main cause of string breakages and unfortunately it cannot be predicted by simply observing them.

Layer 1 serosa type stripes measures are subjected to international standards used on sutures and tennis strings such as 19,16,14,8 mm in width and their length is based on frames used for industrial production of chirurgical threads and tennis (6 to 12 metres)

Later, the stripes form a pack called “bundle”, (made of a hundred strands) which is then salted n order to be preserved and transported.

The use of beef serosa has also brought surprising results:

• High productivity , quick working process, low manufacturing cost
• Easy reproducibility of the different batch of strings
• High resistance to traction

Those advantages allow us to provide our strings to a numerous clientele at a remarkably convenient price, maintaining anyway a certain quality standard, this is a rare peculiarity when talking about sheep gut products. Hypothetically speaking, if string factories ceased to produce beef gut strings, the prices would literally skyrocket because In the past, there were hundreds of these factories, anyway, today the professional ones are just a few.

 

What about sonority?

It is often claimed that sheep gut stripes have better acoustic performances than their beef gut counterparts, nevertheless there is no scientific evidence of that, meanwhile is ascertained now that unsplit gut is superior to both of them.

The truth is that a string’s acoustic performance depends exclusively on its material’s specific weight and on its elasticity. The specific weight of beef and sheep gut is the same, in fact they are both made of collagen; regarding elasticity, it is dependant only on the way the string is made (and it’s measure is the twisting degree). Another important factor are the chemical processes used in stringmaking, which are always kept secret.

In the end, it is possible to produce excellent beef gut strings as well as tremendous sheep gut strings and vice versa.

Our beef gut strings are produced with an ingenious mixture between modern methods to obtain reproducibility, stability and a rapid production process, and old ones to gain the best sonority and durability.

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by ordini

Whole unsplit lamb gut: only a myth from the past, or are they really different?

 

In the production cycle of the XVI, XVII, XVIII and XIX centuries, the animals whose intestines were commonly used in the string-making industry in Rome, Naples, Lyon, Munich, etc. were both goat (expecially in Neaples area) and sheep intestines. The latter category was then subdivided into lamb gut, sheep gut and finally mutton gut.

In the slaughterhouses they used to treat any animal, always for alimentary reasons only; it was then up to the string-maker to select the intestines (coming from different sources and sometimes from very far away) according to their gauges, following the rule, that we have come to know, that the guts of smaller gauge had to be used only for the thinnest strings, and vice versa.

It is particularly interesting the singular situation found in Rome and Naples, where, during Easter time, huge quantities of lambs and young goats were slaughtered, whose intestines were then destined for the production of the Lute chanterelles, which were then sold throughout all Europe.

The common situation that is found in many Italian documents of the XVIII and XIX century is that with three or four whole guts you should get the range of diameters typical of the Violin first string: therefore, the original guts must have been really quite thin.

 

 

A Roman document from the mid-17th century (Attanasio Kircher, “Musurgia Unniversalis”, Rome 1650) even reports the interesting information that the first string of a Lute was made using only a single whole lamb gut:

The use of whole guts was therefore the rule in those countries (such as Spain, Portugal and Italy) where there was availability of small animals that allowed the use of three, sometimes four of their coupled and twisted guts, to obtain the range of diameters suitable as the first string of a Violin.

In other countries (France, Austria, Germany, etc.) the situation was quite different: their lambs, either for the breed, the climate or the type of feeding, were larger than those of Italy and Spain, and were never slaughtered at an early age (even for the good quality of the wool) , as opposed to what happened in Italy. Because of the larger intestine section, it was impossible to obtain suitable diameters for the Violin first string: this is the main reason for the huge orders of Lute and Violin first strings addressed to Rome and Naples by the various European nations in the XVII, XVIII and XIX centuries. There are several documents from the XVIII and XIX centuries, especially from France, which analyze well the situation and conclude that, because of their type of sheep, it was impossible to imitate the quality of the Neapolitan first strings.

This type of problem gave origin to the ingenious solution of splitting the intestine lengthwise and halfway in order to obtain thinner strips so as to circumvent the obstacle, a technique that is still used today by virtually all string makers, whether they deal with beef's casings or sheep's casings.

From the documents that were found, it would seem that this technique was introduced in Germany only in the late XVIII century (the German inventor won a prize from the local municipality), while its use was actually known as early as the second half of the XVI century, at least: in the statutes of the string makers of Rome in 1587, 1591, 1642 and 1678 it was in fact forbidden to make strings from intestines 'split in the middle', under penalty of heavy fines or even whip and jail and the  espulsion from the roman stringmaker’s corporation:

 

 

In the statutes of Lisbon string makers of the late 17th century it was also stated that a string maker who was discovered mixing whole guts with guts cut into strips would be forced to pay a hefty fine:

 

It would therefore be a commercial fraud. An Italian document from the middle of 1846 states that the use of strips to make strings instead of using the whole gut, is to be considered a fraud and it also explains how to detect it:

 

 

But why in Italy and Portugal were they so strict against those who cut / used the gut in strips? Wasn't it an ingenious system to be able to use even the larger and more available casings?

Until a few months ago, it was commonly believed that a string made from whole gut should have the same acoustic properties as a string made from strips. Our recent rediscovery of the ancient system used in Italy to make whole gut strings has instead shown a completely different reality: strings made of whole unsplit guts have greater acoustic performance, they reach a stable tuning more easily, they are more resistant to traction and also much more stable to climate changes as compared to the same string made out with the same intestine cut in strips.

This series of findings would definitively explain why the strings produced in Italy (and to a lesser extent in Spain) enjoyed the reputation that has always been praised in European documents from the late sixteenth to the first half of the twentieth century and also explains why it was so carefully monitored that there were no fraudulent initiatives by local string makers.

 

But does whole gut really sound better?

Absolutely.

As mentioned earlier, uncut whole gut strings not only have proven acoustically high performance in terms of volume and achievable sound nuances, but also have high tensile strength, fast and stable intonation and resistance to climate changes. If we lived in those past times, we would have certainly done everything to preserve such quality by persecuting any form of fraud.

We asked ourselves what could be the reason for this better sound, stability and mechanical resistance: if we make two identical strings from the same gut (but one of which is obtained from strips) we get very different results.

We have come to the conclusion that the possible 'secret' of this special quality is the result of the natural conformation of the intestine, which presents on the one hand a sort of robust and thin longitudinal 'lace' on which the thin and delicate 'tubing' of the intestine adheres. During the twisting phase, it spreads around the above-mentioned lace which, on the contrary, results in traction at its ends, almost as if to create a hypothetical covered rope whose core is the aforesaid 'lace'.

Here is a video showing this:

https://youtu.be/a_a2hlPbzUg

 

 

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by ordini

What is the FL product?

“I installed some new high-quality strings, the nut is perfectly polished and graphite has been correctly applied, but the first string keeps breaking when I get near to the final tuning: why?“

“I bought a small harp for medieval repertoire, but unfortunately the strings on the first octave will break right after being installed, even if they are from a well-known famous brand: why does that happen?“

Here is the fact: you might have followed the best way to install the strings, and you might have used the best strings on the market, but did you ever look into the Breaking Index (also called FL product) of your instrument?

The FL product
When a gut string is gradually stretched, it will eventually reach a specific frequency at which the string will break abruptly: such frequency is called “Breaking Frequency”.

Counter-intuitively, such frequency will remain the same even with different diameters of the string (the only variation will be in the tension of the string, expressed in Kg). The reason is this: if the diameter is increased of a certain percentage, the tension will also increase of the same percentage (and viceversa).  As a matter of fact, applying Mersenne/Tyler string formula, when changing the diameter and the resulting tension, it will be noticed that the frequency will remain unchanged.

As a consequence, both the following statements start from false premises, and therefore will result not true:

“The string snapped: I decided to install a thinner one because it has a lighter tension and therefore it won’t break”

“The string snapped: I decided to install a thicker one because it is stronger”

We have taken several measurements on gut strings of different brands, and the results show that the average frequency value at which a gut string with a length of 1 meter breaks is 260 Hz .

The Breaking Frequency (F) is inversely proportional to the vibrating length (L), so if the length of the string doubles and goes from one meter to two meters, the frequency will be divided in half, and vice-versa. In other words, the product between the two parameters F and L is a constant that, at the unit length of 1 meter, is defined as the Breaking Index, or FL.

When a luthier designs an instrument, he starts, instead, from the frequency of the 1st string: so, dividing the Breaking Index by the frequency in Hertz of the first (and therefore highest pitched) string, we can calculate the vibrating length at which the string will inevitably break.

Let’s make a practical example on a Violin:
The frequency of the first string, the E (considering the baroque pitch of 415 Hz), is 621.7 Hz
Therefore, the vibrating length at which the E string will instantly break is:
260 / 621.7 = 0.418 m = 41.8 cm (Breaking Vibrating Length)

Breaking Vibrating Length and Working Vibrating Length
As we have observed, we can obtain the vibrating length at which the string will instantly break simply dividing the Breaking Index by the frequency of the first string, regardless of the diameter that will be used: these are our Pillars of Hercules.

In order to have a string that does not break, it is therefore necessary to introduce a certain prudential shortening of this limit length, but by how much should we shorten it? If the shortening is excessive, the acoustic performance is compromised: the sound performance of a string, at the same tension and frequency, will be improved if its diameter can be reduced as much as possible by acting on the vibrating length (vibrating string length and diameter are inversely proportional). To find the right answer, let’s take a look at the following graph:

 

 

It can be noticed how the string initially stretches a lot (irrecoverable loss of elasticity, also called “false elasticity”) before following the linear stress/strain trend given by the Mersenne/Tyler law.
At some point that linear trend changes ratio, and the line gets steeper. This has only one explanation: the string has lost its ability to stretch; the breaking point is getting nearer, and it’s only 2 or 3 half-tones away.

Speaking of which, Daniello Bartoli wrote in 1692: “a string shall break when it can stretch no more”:

 

 

Praetorious (‘Syntagma Musicum’, 1612) provides us with both the length measurement unit and the various tunings of the instruments represented in his tables: after deducing the possible standard pitch, in most cases it was found that the various FL products reached the upper limit of the line (a clear reminder of the common rule of that times to tune the first string to the highest allowed), right before the final steep section; we are therefore at two / three half tones from the theoretical breakage of the first string.

This corresponds to a Working Index of 220-230 Hz·m on plucked instruments (2-3 half-tones less than breaking point); 210-220 Hz·m for bowed instruments (3-4 half-tones less than breaking point), excluding large sized bowed instruments, that work around 190-200 Hz·m (see the several works of Ephraim Segerman in FOMRHI bulletins).

 

 

This is also confirmed by our calculations that we have carried out in some historical Lutes and 5 course Guitars kept in museums, provided that the vibrating length has not been altered and that they can be traced back to a sufficiently identifiable standard pitch (see A. J. Hellis:’The History of Musical Pitch’, London 1880, and Bruce Haynes: ‘A History of Performing Pitch: The Story of “A” ‘ 2002).

This is the case of surviving theorboes/ archlutes (for example those of Grail, Buechenberg, Hartz etc ) built in Rome in the 17th century (estimated standard pitch of 390 Hz), renaissance lutes made in Venice in late XVI century- beginning of the 17th century such as for example those of Venere, Sellas, Tieffenbruchker etc  (Venetian standard pitch ‘mezzo punto’: 465-70 Hz), 5 coure guitars made in France in the late 17th/first half of the 18th century -such as the Voboam ones- (standard pitch around 390 Hz), and, finally, the d minor 11,13 course  d minor baroque lutes made in Germany and related Countries in the 18th century (german Kammerton pitch, around 420 Hz), where the calculated Working Index range is 225 -235 Hz·m.

 

In our example of the Violin, the vibrating string length that generates the breakage must be reduced by two . three semitones.

The result is as follows: 34.5-33 cms (range of possible vibrating working length at the pitch standard of 415 Hz)

 

Essential fields of use

Harps in general (also modern harps)

This calculation is particularly useful on harps that, because of their great variety, might not respect this rule: one should mostly concentrate on the first octave, carefully verifying the FL product of either all strings or also in steps. This information should be taken into consideration by luthiers first of all, since they need to plan the harp according to known notes and pitch. Historically speaking, most harps work with the highest octave in conditions of yellow light

Medieval/reinassance instruments

Since no original instruments survived to this day (we make use of iconographic sources only), and the standard pitch of that time is unknown, it’s always worth verifying the FL product before buying any instrument. This information should be taken into consideration by luthiers when they are planning the instrument knowing the note of the first string and the standard pitch to use, as required by the customer.

Newly designed instruments of alleged historical reconstruction

The FL product should be considered in yellow light for Lutes, Baroque Guitars, Reinassance Bass Gambas; it should be considered in green light for bowed instruments, with or without frets (for Violone consider an FL product of 192-200 Hz·m)

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Other fundamental applications of the FL product

How can a string maker understand when to change from a gut string to a wound one?

How to understand when a gut string will not have acceptable acoustic performances anymore?

I installed all gut strings on my bass Viola da Gamba, but the 6^th string doesn’t perform at all

I’d like to install all gut strings on my Viola: can this be done?

I installed very good pure gut basses on my Lute, but they are too dull: why?

 

The FL product is the answer. If on the first string the FL product is also called Working Index, on the other strings this index itself can express the Inharmonicity degree of that particular string in the instrument, having the vibrating string length and the frequency.

Generally speaking, the Inharmonicity degree can be considered as an index of acoustical quality; it will be maximum on the first string, and it will gradually decrease on lower strings until the FL product, and consequently the acoustical performance of the strings, will be reduced to a point where human ear will not perceive it as acceptable anymore (it is widely known that strings of growing diameters, placed on the same vibrating length, will become more and more dampened, will be difficult to be brought into vibration, and will give bad acoustic performances).

At that point the only solution is to adopt a different type of string (wound, roped, KF, loaded, etc).

How can one predict when to adopt such different technological solution? Looking at the FL product, of course!

 

An example for the classical guitar (and all plucked instruments, in general):

The 3^rd string – the ‘g’ – of a classical guitar is the last nylon string; its FL product is around 127 Hz·m (using a scale of 0.65 m and a frequency of 196 Hz for the ‘g’ note)

The 4^th string – the ‘D’ – is instead a Nylon wound string; its FL product is around 95 Hz·m (on a scale of 0.65 m and a frequency for the ‘D’ of 146.8 Hz)

The principle behind this transition is that a nylon or gut string will not be able to give good acoustical performances when its FL product will be lower than 90-100 Hz·m (on the 5^th course of the Lute, the FL product is around 70-80 Hz·m only, but the workaround is using two strings paired in octave).

The 6^th course of a Lute will have an FL product of 59-60 Hz·m; the inharmonicity problem is here resolved only using two strings paired in octave (see Virdung 1511) , but this is the lowest limit: under 60 Hz·m the acoustic performance is so poor that even a paired octave will not do, therefore there’s the need to change to a type of strings that will work down to a limit of 39 Hz·m (wound strings, KF, loaded, Gimped, etc).

 

PLUCKED INSTRUMENTS (i.e. Lutes)

With the 1^st string at 225-235 Hz mt of working Index (that is the best situation for the performance) , the 6th course of a renaissance Lute has an FL product of only 58-60 Hz·m: despite the fact that the inharmonicity problem here is limited by using the paired octaves, this can be considered, generally speaking, the lower acceptable limit for a gut string. In fact, under 58-60 Hz·m, the acoustic performance starts to degrade progressively until it becomes so poor that the paired octaves are no longer enough: it is therefore necessary to switch to a type of strings that will work under 58-60 Hz·m, till the lowest limit of 39 Hz·m, that is the FL product of the 10^th/11^th course (i.e. wound strings; KF, loaded; Gimped; etc).

 

BOWED INSTRUMENTS

On bowed instruments, thanks to the continuous action of the bow on the string, the situation is better: in this case, the transitional FL product can be considered around 60-70 Hz·m . With that being said, it is still possible to have a good performance also when the FL product for the 6^th string is of 57-58 Hz.m only, provided that the gut strings of the 5^th and especially the 6^th strings have a very high elasticity and/or density (roped structure/loaded gut/whole lamb gut). (1)

However, care must be taken so that the FL product should never be under 55-56 Hz.m: under this value, wound strings must be used.

This is the situation that commonly happens with all those instruments whose FL product is less of 200-210 Hz·m.

For example, the 6^th D string of a Bass Viol with a scale of 69 cm (at 415 Hz pitch standard) has an FL product of only 48 Hz·m:  if such instrument would have been designed to use only gut strings, using the correct FL product for the 1^st string (i.e. 200-210 Hz·m), the FL product of the 6^th would raise up to 57-58 Hz·m; as a consequence, the instrument would have a scale of 77 cm, and not only 69 cm.

A pure gut g-string for a Violin at 415 Hz shows an FL product of 61 Hz·m: this means that a pure gut string can be still used, provided that it’s of excellent quality (i.e. very high elasticity). On the other hand, it’s impossible to reach the low c on a Viola da Braccio that has a vibrating length of only 38 cm: its FL product is just 47 Hz·m.

To have a low c in pure gut – of the best quality –, the vibrating length of a Viola should ensure an FL product like the one for the low g of the Violin: 61 Hz·m (in any case, not less of 57-58 cm). Therefore, following the fore mentioned proportions, its vibrating string length should be 47-48 cm (or at least 43 cm as absolute minimum value, that ensures the same FL product of the 6^th string on the Gamba family).

Vivi felice

Mimmo Peruffo

(1) In the case of the Cello, the situation is different: during the 18th century, this instrument never used roped gut strings or loaded strings, in favour of high-twist gut strings instead. In general, cellos worked with higher tensions than those in use on the viola da gamba family: the combination of 'higher tension and high-twist gut strings' can negatively affect the sound output and the quality of the bow's attack. This suggests that when the FL product of the third string is below 70 Hz/m, it is better to use a wound string.

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by ordini

Wound strings for bowed and plucked instruments from the late 17th century to the early 19th century: what do we know?

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by ordini

How to correctly install gut strings in order to avoid breakages and at the same time assuring a fast and stable intonation

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by aquila

Equal tension/ equal feel: some useful information

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by ordini