|Early Music FAQ|
1) Why are gut strings so expensive?
Because their manufacture is still mostly handwork and require a high degree of specialization: there are only a few of us left, worldwide, who know how to make the appropriate gut strings for historical stringing.
Moreover, the whole string making process requires at least 10-12 uninterrupted days of work
2) From which sources do we know that the strings of the string quartet were thicker than those we commonly use today?
Both from available historical sources we found in recent years and from surviving pieces of strings we believe to be original.
3) How important is, as far as quality is concerned, the colour of gut strings?
The colour of a gut string has no influence whatsoever either on acoustic performance or playing life.
Identical strings, different bleaching
Natural colour varies from gut to gut. Extremely white strings (looking like nylon) could betray too energical a bleaching, though.
4) Is it true that strings made of ram's gut can be recognized by their (typical) brown colour?
No, the gut of any animal, if unbleached, always has a more or less brown colour; in other words, such a string (in our example ram's gut) was not bleached and that was a stringmaker's precise choice.
5) Is it true that strings made of lamb's gut are better than those made of sheep's, beef’s or ram's gut?
No. A string's acoustical quality depends minly on two factors: density of the material and the elasticity.
Historical relevance apart, all these materials possess the same density (at the end of the day it is all 'dry meat'). The elasticity, on the other hand, exclusively depends on how the stringmaker produced the string (high or low twist, with the addition of hardening salts & c.). Tests carried out with a double blind method have proven it impossible to detect any acoustical difference.
In any case it is reported that up to the mid-17th century in different italian regions the guts of sheep, lamb, wether, ram, goat, wolf, beef could be indifferently used (see A. Kircher's Musurgia Universalis, Rome 1650).
6) Why do modern stringmakers use guts cut into strands instead of whole guts?
First of all, the cleaving of gut into strands to be twisted into musical strings is a technique that was already in use in the second half the 16th century (see the roman and neapolitan stringmakers statutes from 1589 and 1653) and was certainly common in the second half of the 18th century.
The problem is that we do not know - at least not in every detail - the early steps in the historic whole gut manufacturing technique anymore.
Besides, we must point out that it is, generally speaking, nearly impossible to find lamb's gut that is so thin as to allow us to achieve a historic violin top string made of three whole guts. In practice we always obtain noticeably thicker strings and that is a definite proof that the gut does not come from real lamb (i.e. less than one year old): hence the need to split the guts in half in order to obtain thinner strands. On the other hand we must point out that strings made of gut strands (again, a historically correct method) are of high quality and grant a long playing life.
7) Why can't I use historical gauges on my violin/viola/cello?
There are several possible reasons:
- You haven't got used to playing with thicker strings than my usual, yet. - Thicker strings often exert too much pressure on the sound board and that damps the sound: the pressure can be diminished by reducing the angle of the strings in relation to the bridge by way of raising the string holder at the bottom of the instrument (a solution also adopted in the past) or, if possible, reducing the height of the bridge.
To learn more: please visit the site of Damian: www.damianstrings.com/baroque%20set-up.htm
8) What is the difference between a high twist and a low twist string?
A very important one: a high twist string is much more elastic and that means an increased reactivity: the string will respond more easily both to plucking and to to bowing and produce a wider dynamic excursion and timbric variety. On the other hand a low twist string, being stiffer, is less reactive but more resistant under stress and thus suitable for all trebles in general.
Low and high twist
The material being the same, elasticity and resistance are inversely proportional and that is why it is not possible to use high twist strings as trebles, since they would easily break.
Low twist strings are best suited for Trebles - but not best suited for the mid-register strings, where the acoustic performance would be impoverished.
9) What is a demi-rectified string?
Modern gut strings are machine -polished to a perfectly smooth surface, which inevitably damages the surface fibers.
With half-rectified strings the polishing process is stopped before a completely smooth surface is obtained.
Thus it is possible to imitate the hand polishing of the past and also the surface fibers remain mostly intact. This results in a longer playing life, better keeping in tune and better acoustc performance (broken fibers have a damping effect on the sound).
10) What care do gut strings require?
No particular care.
But in the case of the Doublebass it is advisable to treat the length of the string subject to the action of the left hand with deer fat.
This will extend their playing life.
Lacking deer fat, booth grease will also do successfully tested.
11) What care do wound strings require?
No particular care.
Should the core, under exceptionally cold or dry climatic conditions, buzz inside the winding, the string can be treated with olive or almond oil.
12) What is a string's quality test (so-called Mersenne test)?
In the past it was used to tell a good string from a false one. you pull a string taut, one end in each hand, and you pluck it repeatedly with one finger, carefully watching the cone of vibration.
The Mersenne's test
The cone of vibration must be regular and sharp at the outer sides and free from fuzzy lines in the middle.
This test was commonly done because the hand polished strings allowed for gauge irregularities along the finished string.
Today, thanks to modern rectification, this test is generally unnecessary.
13) What is a string's Breaking Index?
The Breaking Index is the higher frequency a gut string of any diameter can reach at a string length of 1mt. For both gut and Nylgut a mean value of 260 Hz.mt is a good reference parameter. In other words, a 1 meter long string - gut or Nylgut - will statistically always break at 260 Hz, i.e. about 'C'. Hence we deduce that the product of the pitch of the treble and by the string length (more properly called 'Working Index') must always be below this value, under pain of immediately breaking the string at values over 260 or a very short playing life at values between 240 and 260. No problems below 240.
What is its practical use? Example: can I tune in A 440 a lute with a string length of 62cm?
.62 mt (62cm) x 440 (Hz) = 272.8 Hz.mt
The answer is: no, I can't.
What should the appropriate string length be?
A safe index should not exceed the 240 value.
So: 240/440 Hz = .545 mt.
In practice the appropriate string lengt (at A-440) should not exceed 54 cm.
Rule of thumb (assuming the system bridge-string-nut is free from any so called 'cutting effect'):
- Working index within 240: green light.
- Working index between 250 and 260: amber light (the treble could break in a few hours/days, especially by high humidity).
- Working index over 260: red light (the treble will break immediately or within minutes).
Because of the lack of the instrument size standardization, it is important to verify whether medieval lutes and harps satisfy these values, but also where exact copies of original instruments, lutes first of all, are concerned - original string lengths were optimized for the pitches used by the customers of the time, and the pitches commonly in use today are usually higher.
14) What is the acoustical lower limit of a gut string?
It's the maximum diameter able to produce an acoustic performance which is generally regarded as (still) acceptable to our ears (in other words, its inharmonicity level).
This limit is empirical and is above all a function of the string- elasticity.
Other relevant factors are string length, whether the string is bowed or plucked, quality of the instrument and working tension.
Here, too, it could be express in terms of Acoustic Quality Index, i.e. the product of string length by frequency.
Empirically we can say that on a mean size g- tuning lute (60-62 cm s.l. nowdays) a 1mm high twist string (5th course) is dull to the point of requiring an octave.
A diameter of 1.40 mm (6th course in a G tuning - Lute) is the lower acceptable limit for a double twist string (Venice type).
On bowed instruments this limit can empirically be increased by a factor of 1.10.
What is its practical use?
It is useful in deciding, when we calculate our diameters, when we have reached the point where we should switch from a plain gut, Nylgut or Nylon string to a wound one.
Rule of thumb:
- Acoustic Quality Index below 100: a gut/Nylgut/Nylon string begins to lose its acoustical quality (e.g. on a Lute we need octaves).
- Acoustic Quality Index below 80: we need to switch to a wound or loaded string.
15) How do I measure a string's diameter?
Today you can do it with a high-precision micrometer.
One must zero it exactly and be careful not to squash the string while measuring to avoid false readings. And in the past? From about 1830 into the mid-20th century they used a gauge (the first description of one is in Luis Spohr's Violinschule, Vienna 1832).
Louis Sphor’s string gauge, 1832
Luis Spohr's gauge is a metal plate with an acute ‘V’ with gauges scored on the edges: the string slid in until it touches both sides of the V. at this point we read its gauge value.
This method, obviously, allows for a certain margin of approximation. We have no record of similar methods being used in the 18th century.
Marin Mersenne (Harmonie universelle, Paris 1636) suggests winding the string around a small cylinder a given number of times, measuring its length and dividing by the number of spires.
16) How were strings sold in the past?
Present string gauging is a relatively modern praxis, adopted after the introduction of precision mechanical polishing. Up to the beginning of the 20th century a string's diameter was first of all determined by the number of guts employed to manufacture it. a violin treble, for example, was generally made of three guts. This means that, gut being a non-standardizable natural product, the resulting string was not of a constant diameter but fell within a possible diameter bracket. In our violin example the string obtained with three whole lamb guts would have a diameter of between .65 and .75 mm, most probably .68-.70 mm. Strings were usually sold in oiled envelopes containing 30 to 50 strings, all made of the same number of guts: first of all the musician had to select the true strings from the false ones - see 'Mersenne's test - and then select with a gauge and put aside the ones that were too thin or too thick for his purpose.
17) Why are gut strings sometimes varnished?
Gut strings are varnished in order to protect the strings from wear and tear. The varnishing of strings is not a historical process; the earliest samples of varnished strings we have found only date back to the 1920-30s.
A varnished string has a somewhat duller sound and the attack under the bow is slightly more difficult and liable to 'whistle'.
18) What benefits brings the oiling of strings, what disadvantages for the bow's hair?
Oiling is the last step in the string manuifaturing process and makes the string more stable to humidity changes. After a protracted immersion in oil - the coiled string is kept in oil for at least one month - the string develops a longer playing life and a better acoustical performance. The oils traditionally employed were olive or almond
Notice! clean the string carefully with an appropriate solvent before putting it on the instrument: any oil leftovers can contribute to make the bow 'whistle'.
19) What care should be taken with the nut and bridge grooves?
A large number of strings break because of the cutting effect of sharp edges on bridge and nut.
Thomas Mace in 1676 advises: ‘take a knife and make a little impression upon the nut ... [which] must afterwards be filed down deep enough for the string to lye in ... after you have marked the places for all strings to lye in, which may be done with a pencil or pen and ink ... you must take it [the nut] and polish it very well (but especially the notches) ... take a piece of new neats-leather and a little scraped chalk wet in spittle, which with good pains must be rubbed so long till ... the notches be very smooth’.
The well executed grooves in a nut on a guitar by Antonio Torres
All sharp edges and angles must be accurately eliminated. Only after this operation apply some soft pencil lead or very dry soap to the groove. this will not only help tuning and keeping in tune but also prevent the string from squashing and jamming in the groove, increasing the probability of breakage. Robert Dowland, in his ‘Varietie of lute lessons’, London 1610, suggests:’ ...when you set them on the instrument they will sticke (and rise by starts) in the nut, and there breake, even in the tuning: the best remedy when the strings sticke so, is tu rub the little nickes of the nut (in which the strings slide) with a little oyle, waxe, or black lead’.
20) I checked the diameter of a gut string a noticed that it sometimes is slightly different from that declared on the string envelope: is the string faulty?
No, gut is an extremely hygroscopic material and the amount of humidity absorbed can slightly alter the string diameter. on humid days a string will probably present a slightly thicker diameter, on dry days a slightly thinner one.
Practical tests show that a .82mm string on a humid day can measure .84, or .80 on a particularly dry day.
The diameters shown on our string envelopes refer to a standard condition of 20°C and 60% relative humidity.
Such variations influence the string working tension only minimally.
21) How should I store my strings?
The main enemy of gut strings is humidity: keep them in plastic envelopes or in air tight boxes. A carefully stored string will keep its quality for many decades.
22) How do I take care of buzzing in historical wound-on-gut strings?
Historical wound strings, lacking a damper betweeen core and wound wire, in particularly dry climate may present this problem.
Tutors of the past (e.g. Friedrich Dotzauer's ‘Méthode de violoncelle', Paris c. 1830) suggest lightly wetting the whole string with a few drops of olive or almond oil in order to have the gut core swell lightly and make full contact with the winding again.
Never use water!
23) How should I prepare a lute to be strung with gut?
Making sure there are no sharp edges anywhere where they may cause a cutting effect (nut, bridge, string holder - see faq 20).
The length of string winding on the peg shold be as short as possible, avoiding any overlapping spires (which affect the tuning stability) and squashing and jamming the string against the pegbox side (see Thos. Mace's Musick's monument, London 1676). Lutes: we suggest you to visit this very interesting work made by the luthier Jiri Cepelak: http://lute.cepelak.cz/care.pdf
24) What is the Working Index of a string?
The ‘Working Index’ is the product of string legth (in mt.) multiplied by treble pitch (in Hz) and indicates whether the chosen string length is right for the intended tuning.
In other words (see faq 14) whether we risk breaking the treble (when the string length is too long) or a poor sound quality (too short strings produce a duller sound). On lutes and violins it is advisable to keep the Breaking Index in the 230-240 Hz x mt bracket, with the treble working close to its breaking point and granting the best possible sound in the bass register.
25) What is Nylgut and why is it white?
Nylgut is a synthetic material we discovered and copyrighted in 1997: it has the same mean specific weight as gut and a low degree of humidity absorption - ony 10% that of nylon.
We could even call it 'synthetic gut'.
In theory a gut string and a Nylgut one should have the same diameter.
But since nylgut is quite 'stretchy' we advise using a slightly thicker diameter.
Pull carefully but resolutely and repeatedly the string with your fingers while tuning it for the first time (see faq 31).
Concerning the 'cutting effect' follow the suggestions given for gut strings at faq 19. The white colour is simply a commercial choice, an image.
Because of its particular colour the strings catch immediately the eye both in concert and on CD covers, magazines, websites or TV. And that is good for business.
Unfortunately, because of the bow 'slips' on it, Nnylgut cannot be used on bowed instruments.
26) What were typical string quartet stringings in the 18th and 19th centuries?
This is a fairly vast topic and we suggest this further reading.
In a nut shell:
-Violin: gut for the three top strings, wire wound on gut for the fourth.
A wound third is historically incorrect.
Although in the 18th century and exclusively in France an open wound D string was used, which in the 19th century was substituted with plain gut.
-Viola: gut top two strings, wound third and fourth.
-Cello: until ca. 1730: gut top three strings, wound fourth; wound third and fourth afterwards. -Three string Doublebass: gut top two strings, third either plain gut or wound. -Four string Doublebass: as above, wound fourth.
Here we must point out how modern wound strings (flat metal winding on a rather stiff gut core; silk padding between gut core and metal winding; different, metal biased, gut core to winding ratio from that of historical strings) heavily change the real expressive qualities of historic stringings.
27) What are the technological differences between modern and historical would strings?
Historical wound strings present the following general features:
- low or high twist gut core.
- round metal wire winding.
- no silk 'padding' between core and metal winding.
- metal wire of silver, silvered copper, plain copper or its alloys (brass).
- different gut/wire ratio than the modern wound strings.
Pieces of wound strings from the18th century
Modern wound strings:
- flat metal winding.
- stiff, low twist core.
- silk 'padding' between core and metal winding.
- employment of modern alloys like tungsten, nickel, &c.
- metal-biased gut/wire ratio.
Hence the acoustical differences are quite noticeable and interest both dynamic and timbric aspects.
28) What sort of wound strings were in use in the 17th to 19th centuries?
- Close wound: the single wire spires are tightly wound touching one another. It is the still commonly used sort.
- Double wound: a second close wound layer is laid over the first one. Because of the large quantity of metal wound on the gut core they were employed on instruments with a short string length but requiring a low tuning, e.g. violoncello da spalla, 5th double bass string &c.
- Open wound: the single wire was wound so that the spires would not touch one another but with a space in between equal or slightly wider than the wire diameter (see F. le Cocq, Paris 1724); these strings were in use exclusively in the in 18th century as transition between plain gut mid-register and close wound basses, e.g. Bass viol 4th, violin 3rd &c.
29) Why can't we consider equal tension stringing a historical option?
The concept of equal tension as expressed in equal number of kg is modern one, probably making its first appearance about 1860 (Maugin-Magne, ‘Nouveau manuel complet du luthier’). Up to the mid-18th century the tension of a string was exclusively understood in terms of feeling of stiffness to the touch, which is something different from the way we understand it today. While the amount of tension is solely expressed in kg, a feeling is conditioned by a number of parameters, such as string length (this is why theorbo- diapasons, if tuned with exactly the same tension, feel so much more slack than the fretted strings), type of string and diameter.
In a set where all the strings are calculated with the same tension in mind will feel quite different to the touch: this contradicts the criteria of the 16th and 17th centuries, which require that all strings present a homogeneous feeling under the fingers.
In conclusion, the string type being equal, a set of string, in order to present a feeling of equal tension, must actually have an scaled tensions.
Click here for further details.
30) What should I do when I put a new string on?
Once checked that all points of contact are smooth and free from sharp edges, when tuning a string for the first time, pull it with your fingers until it stays in tune: moderately the trebles and wound strings but with a bit more energy the thicker ones.
This applies to both gut and synthetic strings, especially to Nylgut.
31) What should I do when I am not going to play for some time?
Follow Thos. Robinson's advice (begin of the 17th century) and tune the treble a bit lower, thus reducing string-stress.
32) What is the difference between historical and modern stringing praxis (violin, viol, cello)?
Quite a substantial one: research on historical sources and observation of surviving pieces of original strings point to the use of not only thicker than commonly in use today, but also hand polished (hence not perfectly smooth) strings. Now, choosing to use historical string diameters can sometimes lead to a readjustment of the instrument's set up - especially concerning the angle of the strings on the bridge - which sometimes the instrument itself does not accept very willingly.
This is why beside a historical stringing (which we always find desirable) we also propose a modern one (in light, medium and heavy grading).
33) How do I work out the right working tension?
Finding the right working tension for each instrument is basically an empirical process, depending on tipe of instrument, type of string and personal musical attitude.
In other words, there are no specific mathematical furmulae for it. What we do suggest is: put a 2nd or 3rd string on the instrument of a diameter you consider adequate (bowed or plucked, the process is the same).
Tune the string to the wanted pitch and check whether it feels too slack or too taut according to your own perception.
Lower or raise the pitch by as many semitones as necessary to bring it to the right tension, that is to the point where it feels right to you, neither too slack not too taut.
Now apply the following indications:
-The string was originally too taut: multiply its diameter by .944 by the number of semitones by which you decreased the starting pitch (.944 reduces a given diameter by a semitone).
-The string was originally too slack: multiply its diameter by 1.059 by the number of semitones by which you raised the starting pitch (1.059 increases a given pitch by a semitone)
Example: I put an .82 third string on my lute (or any bowed instrument) and it feels too slack.
Solution: starting from the string tuned at the wanted pitch, raise it semitone by semitone until the tension feels subjectively right. Let us suppose you raised it by two semitones: multiply 82 by 1.059 twice: the diameter you want is 91.9(6) mm, i.e. a 91 available as standard on the market.
34) Why do my strings 'whistle' under the bow?
There can be several causes, sometimes more than one at once.
A very common one are oil leftovers from manufacturing: clean them carefully with a rag damped with ‘white spirit’.
35) Why did the string break as soon as I put it on the instrument?
There are three possible reasons:
- The string is faulty.
- The string length is too long (exceeding the Breaking Index).
- Some point of contact between string and nut, bridge or string holder has a sharp edge or is lacking appropriate lubrication (i.e. pencil-graphite etc.).
- Faulty string: generally it does not break cleanly but through progressive fraying, usually announced by little hairs raising along its length.
- Excessive string length: check whether the product string length by frequency is in excess of 240, regardless of type of instrument: lute, baroque guitar, fiddles and medieval instruments in general.
- The cutting effect of sharp edges usually results in a sudden and clean break. It can also be caused by nicks in the string, as consequence of careless.
Notice: the string breaks under tension: if the damage took place at the nut edge, for instance, the breakage will seem to correspond to, say, the second or third fret, since the string is no more under stress. likewise, if the damage took place at the bridge, it will seem to have broken somewhere between it an the string holder.
36) I used a Venice string as treble: why did it break immediately?
Venice strings possess a high degree of elasticity, noticeably more that a high twist string.
But being elasticity and resistance to stress inversely proportional this type of string should not be used where the Working Index (i.e. the product of string length by frequency) exceeds 140Hz x mt (which generally is the working index of treble strings).
37) I put DE type wound basses on my lute but they seem to be a bit dull compared with other wound strings. Why is that?
DE wound strings were conceived with the purpose of filling in a gap in the area of bass strings for short extention archlutes and swan-neck baroque lutes.
The ratio nylgut core / metal winding is core biased, in order to counterbalance the typical sound of regular wound string, characterized by a very long sustain, rich in overtones and poor in fundamental. in other words a bit too guitar-like. On the other hand DE wound strings on fretted courses are quite fundamental-heavy and require the use of octaves. Like in the old times, in fact. The core bias is aimed to recreating the sound of our loaded gut basses.
38) I put on my instrument a Venice type string of the same diameter as the previous high twist plain gut and it feels much slacker: why is that?
According to the string formula two strings of the same material and same gauge, string length and pitch being equal, will also have the same working tension provided the diameter remains the same also under stress.
But in practice this happens only if the strings are also manufactured in the same, identical manner.
In other words they must stretch by same amount under the same stress, thus reducing their diameter by the same amount (empirically proven by the same amount of peg turns needed to tune them).
Because of its nature a Venice string stretches noticeably more than a regular high twist string, which leads, under equal stress, to a somewhat thinner diameter.
Hence the necessity to use a thicker starting diameter: under working stress it will settle to a diameter similar to that of a regular string's and will eventually lead to the same working tension.
In practice the correct diameter of an equivalent Venice string is obtained by multiplying the plain high twist string diameter by 1.07.
39) Is it true that in the 19th century wound on gut core strings were used on the Guitar?
No, historical evidence has proven that both six course (in late 18th and early 19th centuries Spain) and six string guitars were only strung with wound on silk basses. silk was used until nylon multifilament was introduced about 1950s.
40) Is true that the Guitar in the 19th century was noticeably lighter strung than today?
No, presently available evidence (with particular reference to the tutors of Sor, Carulli and Aguado) shows that the same diameters were used as on the violin; string tensions are practically comparable to those of the modern classical guitar.
The one exception is the 19th century neapolitan guitar (Fabricatore, for example): some documents point to tensions slightly lighter than on the violin.
Besides, the tension profile was less scaled than commercially available guitars sets suggest today.
We advise to always carefully check whether the bridge is soundly glued in place before stringing an original guitar with a modern string set.
41) I tried some Venice type as bass strings on my Bass viol, but I am not satisfied since they sound very dull (especially the sixth does): why is that?
This is a fairly frequent problem and is generally not to be blamed on the strings. the main cause is that the instrument's string length is too short for the required pitch if you intend to string your instrument entirely with gut.
Before the adoption of wound strings - which made their first appearance in the second half of the 17th century - the Gamba family had noticeably longer string lengths than those commonly in use today. From Mersenne's tables was calculated that the bass viol had a string length of c. 85 cm against the 68-70cm commonly in use today.
Likewise modern tenor viols have 55-56cm against the 58-62 which were common in the late 16th / early 17th centuries.
Historical instruments were designed with a longer string length in order to have the trebles work close to their breaking point (Working index not lower than 220 Hz x m - see faq 14).
This was the only way to grant every string the minimum diameter possible, basses first of all.
In fact string length and diameter are inversely proportional.
Reducing a string's diameter (tension being equal, of course) is always beneficial to the quality of sound and bow attack. Exactly what basses, the most problematic of all strings, need.If, on the other hand, the strings length is reduced they will have to be thicker, which will negatively influence the sound quality because of the string's increased inner damping coefficient ('inharmonicity' index).
Solutions to the problem?
1) Use instruments with string lengths typical of the period preceding the appearance of wound strings, i.e. 82-85cm for the Bass, c. 61 for the Tenor and c. 41 for the Treble (see proportions in Thos. Mace's Musik's monument, London 1676).
This way gut strings will give an excellent, prompt sound.
2) If possible (i.e. if the bridge height allows), move the bridge towards the base of the 'C' cuts, thus increasing the string length and improving the acoustical performance in general (do remember to calculate the string diameters keeping this added factor in mind).
3) Employ wound strings (but only in case a more appropriate instrument is not available or you are not willing to lower the bridge position - which is a historically correct trick).
42) Is it true that a sharply bent string completely damaged?
A gut string that has been sharply bent shows a whitish 'nick' at the bending point.
This indicates a slight loss of fibre cohesion but does not mean at all that the string was damaged. The string is still perfectly intact. Signs of serious damage are:
a) the string has been indented
b) the fibres became untwisted to the point of coming apart and the string is not cylindrical anymore.
443 My instrument has a 'wolf': what can I do about it?
Try knotting the string the way the ancients did:
Unfortunately there is no exact procedure about it, you simply have to try experimentally with each string.
To be avoided with wound strings, tholugh!
44) I though that giving you the diameter of my wound string for replacement, but I heard that is useless: is that true?
Yes. Knowing the diameter is useful for strings made of only one material, like plain gut, Nylon, Nylgut or any metal.
Wound strings are composed of different materials and so they can be defined according to the following parameters:
a) 'Equivalent Solid Gut'
b) 'Metallicity Index'
Equivalent Solid Gut
since wound strings are made by coupling different materials we decided to define them in terms of equivalent solid gut: in practice we refer to the diameter of a theoretical gut string possessing the same weight per unit of length as the wound string in question. For the same pitch and string length we'll thus have the same working tension. And this is important to work out our string diameters.
How can we work out the ‘equivalent solid gut’ of a wound string we want to replace and we know nothing about?
Answer: we weigh the string on a scale reading weight in grams and we measure the length of the string. We then divide the weight in grams by the length in meters and then take the square root of the result: that will give us our equivalent in millimeters.
Example: the wound string weighs 35.5g and is 98 cm long: 35.5g/0.98 m = 36.22, whose square root is 6.05. In practical terms our wound string is equivalent to a 6mm thick plain gut string.
the same equivalent solid gut can be reached by numberless percentage relationships between gut and metal. Obviously increasing the one implies decreasing the other by the amount that is necessary for keeping the weight of the string, i.e. its equivalent solid gut, constant.
The higher the gut component, the duller will the sound tend to be, the higher the metal component the brighter the sound. So the 'correct' metal-to-gut ratio mainly depends on the particular timbric/dynamic mixture any given combination can produce and is subjectively felt as 'aesthetically pleasing'.
In other words, there is no objective formula in deciding what the right mixture is. Once decided what the gut equivalence, i.e. the correct working tension, of a string should be, the ratio metal to gut can only be worked out through experience.
The Metallicity Index is also connected with the position of the string on the instrument. The third string on a cello must clearly have a lower Metallicity Index than the fourth, which must have a higher percentage of metal in order to compensate the loss in brightness caused by the lower Acoustic Quality Index for such string position (see Q 15).
Two strings of the same gut equivalent value can possess a completely different Metallicity Index.
Let us take, for example, the third string of both a viola da braccio and a cello.
On the viola da braccio C we will find a noticeably higher Metallicity Index than on the cello G. And this is why we cannot use a cello G in place of a viol C: the working tension might even turn out to be correct, but the acoustical result will be completely unsatisfactory.
Mimmo Peruffo 2007
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