Jan James

Practical Acoustics ofInstruments

of the Violin Family(Bridging Science and Art)

First English Edition

Henry Strobel Publisher

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Henry Strobel, Violin Maker & Publisher10878 Mill Creek Road

Aumsville, Oregon 97325 USA

www.HenryStrobel.com

First English EditionMarch 2002

ISBN 1-892210-05-3Library of Congress Control Number 2002103631

Copyright © 2002 Henry A. Strobel

All rights reserved. No part of this book may be reproduced in any formor by any means without the prior written permission of Henry Strobel.

Printed in the United States of America

This book was first published in Dutch in 1999 asAkoestiek van de Instrumenten van de Violenfamilie

by Broekmans & Van Poppel, Amsterdam.

This edition was set by Henry Strobelin Adobe Caslon using WordPerfect

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7. The Bow

7.1 A short history

A stringed instrument without a bow is almostuseless, on the other hand a bow without aninstrument is also meaningless; the two belongtogether. There are no definitive indications thatbowed instruments have always been preceded byplucked ones [67]; bowed instruments have existedlong before the violin family appeared.

It is a curious fact that it is a relatively recent notion(since c. 1950) that the bow is of major significancefor the sound quality and that there are largedifferences in character among different bows. Thiscorresponds with a major rise in bow prices. Untilthe end of the 19th century the bow was consideredto be an accessory of a certain, but secondary,significance. Nevertheless, the most distinguishedsoloists of that time (Joachim, Ysaye) played withthe best bows of Tourte and his followers. It istypical that the firm Hill & Sons, who startedmaking bows near the end of the 19th century,employed such specialized bow makers as S. Allenand W. C. Retford and that these bows werepresented (with a case for the violin) to buyers ofquality instruments. In that period around 1900there was a buyers’ market for violins, a large supplyand low prices, and certainly little interest in a newbow. The Hill firm later demanded high prices fortheir bows and the best Hill bows from the period1890-1940 are now much sought after. Themanufacture of bows by Hill and Sons graduallytailed off after 1960 and in 1992 the entirecompany ceased to exist [72].

For some reason France had become a centre ofbow making producing a number of great names;Italy has played little or no part in the developmentof the modern bow. Germany has been importantin the mass production of middle and lower gradebows, with one or two individuals making top classbows and England has had only a few excellentmakers. Because of the lowly status of bows in the17th and 18th centuries, very few have survived; a

damaged or unsatisfactory bow for various reasons,was simply thrown away. Those who manufacturedbows in this period (usually violin makers’assistants) were held in low esteem. Not until latein the 18th century did bow making become aseparate profession and the practice of stamping abow with the real maker’s name only became widelyestablished after 1800.

In contrast to the instruments of the violin family,the bow has undergone quite an extensive evolutionin the period 1700-1800, of which only a fewoutlines are given here. The bows from the 17thand early 18th century, only a few of which havesurvived including one made by Stradivari [7], hadthe hair ribbon and stick parallel. Bows withoutwardly curved sticks have been used in the vielle(the medieval precursor of the violin) and in folkmusic instruments (rebec, the Celtic crwth, and theMongolian fiddle) but it can safely be relegated tothe world of phantasy that such arched bows wereused in the Bach period to facilitate the playing ofchords.

These early bows, sometimes called Corelli bows,were mostly rather weak and had a high nut; theyare very well suited to playing fast successive noteswith a light tone, as often occurred in music of thatperiod. Due to the construction of the bow(without an inward curve or camber) the playing ofchords was easier than with later bows because thebow hairs had little tension and could be bent overthe strings. The head had a more pointed end(pike's head) than the more hammer-like shape ofthe present day bow; different types of wood(snakewood, iron wood) were used for the stick.The length was variable, for the violin between 60and 70 cm and a weight of 50 g. Boyden [7] warnsthat the bows of before 1780 should not beregarded as primitive and crude; for much musicfrom the 17th and 18th centuries they are clearlysuperior to the modern bow. Copies of these oldbows have been made by modern bow makers forsuch music.

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Fig. 7.1 The nut of a violin bow on the stick. a. Slide of mother-of-pearl with behind it b. the metal silver plate which may or may notform a whole with the heel plate at the back of the nut. Other partsare shown in fig. 7.2

Fig. 7.2 The same nut as in fig.7.1 detached from the stick toshow some parts and the adjustment mechanism. 1. Silverwrapping 2. thumb grip 3. lower part of the stick with the mortise4. nipple 5. hair ribbon 6. metal ferrule 7. ebony frog withmother-of-pearl eye 8. metal underslide which moves over the(octagonal) lower part of the stick 9. screw-eye screwed into theebony nut and which is moved in the mortice by means of thescrew ( 10) 11. button adjuster with metal rings over ebony.

In the second half of the 18th centurychanges in music practice necessitated abow which permitted the sustaining of longpowerful notes. To meet this need bowshad an inward curvature of the stick, thecamber, giving the middle part of the bowgreater stability. Bows from the periodafter 1770, with a light camber and asomewhat shorter head, called of the“transitional” type , are intermediarybetween the old Corelli type and theTourte type at the end of the 18th century.A bow much used throughout Europe inthe last quarter of the 18th century was theCramer bow, named after a Germanviolinist from around 1750 [54]. Thesebows were manufactured by anonymousworkmen: Cramer himself had nothing todo with their production. In general, bowtypes were associated with players, notmakers.

Shortly before the end of the 18th century,it was the great bowmaker François Tourte(1747-1835) who determined the presentday form of the bow and the choice ofmaterials for stick, frog and head, buildingon work of his father and othercontemporaries. Since Tourte’s day thewood of choice has become pernambuco;after being cut to the right size the bow isthen bent to the right shape by heating. Itis said that Tourte used the pernambucostaves of South American rum barrels lefton the Paris quay from which to cut hisbows, but this does not seem to be aplausible story. This tropical wood wasgenerally used in the 18th century to extractcoloured products for textile dyeing. It is anice detail that one of the earliest markedpernambuco bows carried the stamp“teinturier,” probably a pseudonym,pointing to this relation [41]. Originally,the sticks were only oiled; in the course ofthe 19th century the application of a shellacfinish was adopted.

7.2 Portrait of the present-day bow

Ignoring all details about the evolution of the nut, the headand the attachment of the hair ribbon [7, 67] the modernbow will be described here in some detail first. The figures7.1-7.3 provide a general review of the bow, its parts, and thecorresponding technical terms. The hair is retained inmortices in the head and nut with small wooden wedges; it isstretched by pulling the nut back along the stick by means ofthe screw adjuster. For this treatise, technical details aboutthe exact fixation of the ends of the ribbon in head or frogand how to rehair a bow are of no importance [16, 50, 83].

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Fig. 7.3 Head of a similar bow as in fig. 7.1 and 7.2(slightly larger than actual size). The thin ivory or silvertip-plate is clearly seen; a tiny piece of this plateextends at a right angle to it at the extreme end,shaped to protect the wood at the peak (downwardpointing arrow). Usually a thin plate of ebony isinserted between the wood and the ivory or metal ofthe plate (small arrow pointing left). The head ishollowed to hold the knot at the end of the hair and thesmall wooden plug wedges it in place. The shape ofthe head and that of the so-called throat at thebackside (large arrow) is typical of a particular makeror school so that in combination with the nut (when thisis original) and characteristics of the stick, identificationof the bow can be made by an expert.

The frog (also called nut or heel) is a fairlycomplicated construction of wood (mostly ebony,sometimes ivory or tortoiseshell), metal (gold, silveror nickel or gun-metal) and mother-of pearl, withan iron screw which fits into a screw mechanismfixed to the wood of the frog and which serves tomove the frog to and fro for the adjustment of hairtension (fig. 7.2, 9). The frog is moved over thestick via an underslide liner of metal secured by tinypins or screws to the frog (fig. 7.2, 8). The entireconstruction of the frog - although themeasurements are more or less standardized - ischaracteristic of a maker or a school, and thematerials used say something about the quality, atleast in the eyes of the maker. The bow makermounts his best work in gold, but in itself a gold-mounted bow does not mean an excellent bow; thisdepends on the standards of the maker. On theother hand a nickel mounted bow does not meanthat the bow is inferior; quite a few of the “studenttype” bows from French ateliers can be excellent.The ferrule and the button of the adjuster arealways made of the same metal, the button oftenwith metal bands sandwiched in an ebony cap. Forthe players of old music, modern bow makers makecopies of old bows of the Corelli or transitionaltype; they are however usually provided with a morecomfortable adjustment of the hair tension than the“crémaillère” of older times, in which the frog washeld in place by a series of iron indentations on thebow stick near its lower end [36].

It will be clear from the foregoing that thereplacement of a frog by a new one (e.g. because ofirreparable damage or wear) will reduce theauthenticity of a bow and consequently itsmonetary value, although its playing qualities arenot necessarily affected. To a lesser degree, this alsoholds for the button. In some cases, with a veryvaluable bow, wear and tear of the frog can beprevented by using a custom-made replacementfrog for playing, keeping the original frog separate.In bygone days when money was scarce, materialsexpensive and labour cheap, many French bowswere mounted in nickel to make them affordablefor poor musicians. These bows have sometimesbeen re-mounted in silver to mark up the price.

Nickel mounted French bows are seen less oftennow, although they were made in large numbers.

The brand on the stick does not necessarilymention the name of the maker; often such a brandis only a shop or atelier stamp put on bows boughtby the dozen from specialized bow makingworkshops. Stamps have often been faked toupgrade the value of the bow, in analogy with falselabels in instruments; an expert is usually able torecognize these. Factory bows are routinely brandedwith the names of the makers of which they arecopies. Apart from the stamp (if present, and notalways reliable) and the characteristics of the frog,the model of the head and the way it is cut is ofimportance for the recognition of a maker or aschool. The head plate (fig 7.3) is usually of ivory,sometimes of silver (especially with English bows)or of gold with bows with a gold-mounted frog.

Since 1800 most bows have been made ofpernambuco wood (Caesalpinea echinata), a verydense and strong type of wood with the necessaryresilience. It usually comes from northern Brazil,but not necessarily the Pernambuco region from

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BowType

Lengthof Stick(cm)

Weight of Bow(grams)

Lengthof Nut(cm)

FerruleWidth(cm)

Violin 74.5 60 (57-63)

4.5 1.3

Viola 74 70 (68-74)

4.8 1.4

Cello 71.5 80 (74-84)

5.1 1.5

Bass 72.5 125 (100-150)

6.8 1.8

which the name is derived. Brazilwood, a lesserand more widespread variant of the genusCaesalpinea, originating from different regions inSouth-America and South-East Asia, is used forcheaper bows. Brazilwood can be recognized by itsmuch coarser grain and more fibrous structure thanpernambuco. Whereas bow sticks made from goodpernambuco do not lose their elasticity andresilience even after 100-150 years, Brazilwoodbows get exhausted after a certain period of timeand become weak.

Bows are usually circular in cross section (orsometimes egg-shaped, slightly broader across thelower half) and decrease in diameter from thehandle towards the head. Based on the bows of F.Tourte [67], J.B. Vuillaume has calculated theoptimal decrease. It is questionable, however,whether even bows from the Vuillaume atelieralways meet these requirements exactly; bowmaking is an artistic handicraft. There will be agreat many bows which meet the criteria ofVuillaume precisely, but which are of no interest,whereas a number of great bows do not meet thesespecifications at all. At the thickest end of the bow,the so-called handle, all bows have a more or lessoctagonal cross section (fig.7.1) which enables thefrog to be fixed with its underslide on the stick sothat is laterally stable (very important for theplayer), and does not interfere with the to and fromovement of the frog for adjusting the tension ofthe hair ribbon. Many bows are octagonal over theirentire length. Planta [61] has calculated that anoctagonal stick, compared to a round stick of thesame over-all diameter, would have 15% morestiffness. Apart from the round or octagonal shape,some bows have been made which could be calledrounded octagonal or oval shaped.

Many experiments have been made with materialsother than wood. J. B. Vuillaume had some successwith hollow metal sticks. It did not become a realsuccess with players, in spite of a laudatory letterfrom Paganini stating that it would be superior toa wooden bow [47a]. They tended to bend, buckleand rust and were less durable than wooden bows.They have become museum pieces.

More recently, after years of experiments andfailures, bows have been produced with sticks madefrom synthetic materials, e.g. from polycarbonatefibres which have been made stable by resinimpregnation. In view of the difficulty in obtaininggood quality pernambuco wood, some young andadequately trained bow makers have recentlyproduced bows which in terms of weight, elasticityand resistance approach the conventional bow, buthave a stick made of such synthetic material [37].The newest development is even a device enablingthe resistance of such a stick to be regulated by ascrew mechanism. Time will tell whether this is aviable development. In the past such developmentshave first created a furore which is forgotten later(e.g. the steel bow); so far this seems a seriousnovelty. In the rather conservative world of lutheriea certain resistance can be felt to sticks of syntheticmaterial and it has happened that an enthusiast ofthe carbonate bow, when he brought it to his localshop for rehairing, was refused help.

To conclude this section on the anatomy of thebow, standard measurements of the present-daybow are shown in table 7.1. Different aspects suchas weight, balance and other properties of the bowwill be dealt with in the next sections.

Table 7.1 Standard measurements of the bow

Note: The variations in length of the bow are, especiallywith older bows, considerable, e.g. for the violin thestick length may vary from 72.8 to 75.2 cm

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Fig. 7.4 A bow hair from a ribbon played for some time, after cleaning so that the pattern of theflat scales can be observed. (electron micrograph made with a scanning electron microscope,magnification about 800x; in reality this hair measures about 0.1 mm in diameter.)

7.3 The hair ribbon

The ribbon of a violin or viola bow contains 150-180 hairs, depending on the size of the ferrule, witha weight of 3½-4 g. A cello- or bass bow containsmore hairs with a weight of 5-6 g. The hairsoriginate from the tails of horses all over the worldand sometimes from their manes too if they arelong enough. There are special dealers in horse hair,who clean it and select it on the basis of length,thickness, regularity etc.

Horsetail hairs (like the much thinner human hairsand all mammalian hairs in general) are covered onthe surface with a layer of flat keratinized cellsimbricated with their free edges all lying in thesame direction, the cuticula of the hair shaft(fig.7.4). Rosin attaches to these minuscule surface

irregularities, also by electrostatic interaction,causing the friction enabling the stick-and-slipmovement when the string is bowed and resultingin the actual vibration of the string in a standingwave (see chapter 4).

It has been known for a long time that protrusionsoccur on bow hairs but, due to unfamiliarity withthe actual aspect of the hair surface, these have beenconsidered to be a kind of barb which would beresponsible for the resistance of the hair on thestring. Following the idea that should all the barbspoint in one direction then the bow might onlygrip in this direction, it had become customary tolay new hairs in bundles of 10-15 in oppositedirections. Although one glance at fig.7.4 revealsthe obvious primitiveness of this concept, manyindustrious atelier assistants world wide still

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Fig. 7.5 Micrograph of an Anthrenus larva on bowhairs; magnification 16x (further details see James[34])

alternate the bundles of hairs. Anothermisunderstanding is that the scales of the cuticulawear off easily causing a loss of ‘bite' of the hairs.There is a certain degree of wear and tear but thisdoes not occur in the short term, say up to a fewhundred hours of playing. It is a layer of modifiedrosin overlying the cuticula scales which causes theloss of resistance. This accumulation of chemicallymodified rosin is partly due to the hightemperatures developing at the hair/string contactpoint during vigorous bowing; this can beconfirmed by an infrared camera [59]. This layermay be removed by cleaning the hairs with a 70%alcohol solution on a piece of cloth (taking care notto touch the stick), resulting in an increased ‘bite’ ofthe hairs when new rosin is applied [33]. This maybe of importance for a travelling musician, who maydistrust the abilities of the local craftsman to rehairhis valuable bow. Even under other circumstancessuch a cleaning is better than a hasty rehair at alocal shop with its risk of damage to the head. Howoften a rehair is really needed will vary; forprofessional players the average is about every sixmonths or when the bow does not seem to hold thestrings as it once did.

In spite of extensive experiments with variousmaterials, it has so far not been possible to replaceby a synthetic material the time-honoured horsehair which had been used for stringed instrumentsin the Arabic world even before the violin familycame into being. In contrast, replacement of theclassic catgut core for strings by synthetic materialshas met with more success (chapter 8).

As a natural material , bow hair is susceptible to aparticular parasite, the bow bug (museum bug,Anthrenus museorum), especially its larva. It iscalled a museum bug because the larva in questionmay eat the keratin from furs, wool and hairs aswell as the protein skeleton of entire insects in anatural history museum. If many loose fragments ofbow hair are found in all directions on opening aviolin case that has been closed for a long time,then you can be certain a bow bug has been atwork. The larvae have a preference for the dark andmay stay for years in a closed case and feed on the

keratin which forms the basic protein of the bowhairs [34]. The larva is a few millimeters long andhas bristles all over its body (fig. 7.5). It does notshow any interest in any other part of the bow butthe hairs, nor for the violin or parts thereof. Woodis the speciality of the woodworm (Anobiumpunctatum), no relative of the bow bug. Aftermetamorphosis the bow bug becomes a flying insectand feeds on the nectar of plants. Any such oldviolin case with broken hairs should be taken outinto the open and treated with an insecticide spray.

Rosin is a subject which has often been neglected;it is, however, essential for the functioning of astringed instrument. The best instrument with anexcellent bow is unable to produce any soundwithout rosin. The way in which rosin is attachedto the hairs and the stick-and-slip mechanism itcauses has been dealt with in the previousparagraph and in chapter 4; the proper use of theright kind of rosin makes a difference to the playingquality of a bow and the tone it evokes from theinstrument [67].

Rosin (called colophane in French and in GermanKolophon after the region in Asia minor where goodrosin used to be produced) is originally the residueleft when turpentine has been distilled from the sapof resinous trees. New (semi-) synthetic procedureshave since been developed to make rosin, andcertain substances are sometimes added. Thecharacteristic smell of rosin is attributable to certainvolatile etheric oils; this is the reason why it is bestto keep rosin in a closed box or envelope. The

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colour of the rosin is related to the melting point:dark rosin has a lower melting point than lightrosin. Dark rosin is soft and more tacky; lightcoloured rosin is somewhat harder, powders easilyand, especially in cold surroundings such aschurches, sometimes does not grip effectivelycausing non-response and whistling. In a hotclimate hard, mostly light rosin is to be preferred.For the cello and especially the double bass, tackyrosin (which may or may not be dark) is best.

With violin and cello, the use of light or dark rosinis also dependent on the properties of the bow: if ithas a very strong stick the chances are that lightrosin might give insufficient grip, especially withstiff strings and in cold weather. On the otherhand, with a flexible bow, a vigorous attack in asolo may be realized more easily with a hard rosin.Each player has to find out what is best for hisplaying and his equipment; it makes sense to haveboth light and dark rosin to hand, particularly inview of different atmospheric conditions. Apartfrom dark and light types, also rosin has beenproduced which contains a kind of lubricant whichworks satisfactorily for some players. Thedifferences between the various brands of light anddark rosin are not very great.

Rosin should only be applied when necessary, i.e.when there is clearly a loss of grip on the string. Itshould be applied with long even strokes; short toand fro movements generate too much heat. Forthe first application after rehairing a powderedrosin is advisable because it adheres more quickly tothe scales of the cuticula of the hairs. Excess rosinis played off quickly, but it might cake onto thestrings (thereby altering their mass) or onto thetable. This can easily be wiped off, but sometimesthe rosin on the strings is difficult to remove,causing them to sound false (because of the localmass increase). Moreover, a detrimental effect onthe tone may occur when, during bowing, rosinslides over rosin. When the rosin cannot be wipedoff easily, cleaning the strings with a minute drop of70% alcohol (or eau de cologne) on a piece of clothis indicated, taking care not to spill any alcohol onthe varnish of the table. The cleansing towelettes

provided with aircraft meals serve very well in thisregard!

7.4 The bow as a tool for the player

The attitude of players towards the bow differswidely; some are quite indifferent, others are verycritical. It has been well established that thecharacteristics and the quality of the bow are veryimportant for the ultimate tonal result, and that thebow and the instrument should also match. Thereis no such thing as the ideal bow for everything andeverybody, although good bows have much incommon.

Any player handling a good bow for the first timeis often surprised how easily all the different bowstrokes can be executed, and even an unhappy“landing” on the strings seems to be effortlesslycorrected due to an excellent response. The resultwith regard to tone production is also surprising.The experiment with a hidden player tryingdifferent quality bows on the same instrument isillustrative: the audience often thinks that differentinstruments are played. The difference betweencolourless mass-produced bows is usually inaudible.As with instruments, clear differences exist betweenvarious players who may draw entirely differentsound colours from the same bow and the sameinstrument. Players usually agree on the response ofa bow, i.e. the more or less rapid establishment ofa Helmholtz vibration in a string.

A good sounding bow and one which is easy to playdo not always run hand in hand; some bows, amongwhich real Tourtes, have a beautiful tone but maybe difficult to play for different reasons. It remainsmysterious just what determines a beautiful tone.Far fewer investigations have been made in thisrespect than with violins. The tone is a product ofresponse and damping of a bow in which the ribbontransmits certain vibration patterns to the wood ofthe stick, which plays the most important role intone formation. The diameter of the ribbondetermines the force which can be exerted on thestring, but also the damping: the broader theribbon, the more damping. The damping effects a

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selection in the harmonic spectrum of the vibratingstring. A good tone is produced when all parts of abow combine harmoniously [21a].

Instruments differ in their demands on the bow;moreover there are differences between bows forvarious members of the violin family. The fact thatviolin and viola are played in a more or lesshorizontal position and cello and bass with thestrings more upright, are of importance for theconstruction of the bow.

An important element in the adjustment of a bowis the curvature of the stick in both horizontal andvertical directions: there is no point in testing thequalities of a bow as long as these factors are not inorder. As explained in 7.2, the modern bow (sincec.1800) has a curve towards the hair ribbon, thecamber. For setting the camber the shaft is heatedthoroughly (yellow gas flame), equally and evenlyon all sides and then bent while hot, using bothhands. For mass production steam is used. Ifeverything has been done optimally, the “belly” ofthe stick touches the hair about half-way. Manyold bows have in the course of time lost somespring, causing insufficient tension on the hair andtoo weak a “feel” of the bow for the player in viewof the strength of the stick; furthermore they maybe curved laterally to the wrong side. A bow makercan easily correct this by re-springing the stick byheating as outlined above. This does not make aweak bow stronger, however, but its playingqualities can be improved. The desired result is notalways obtained; pernambuco has a will of its ownand warping may occur. The well known Londonbow maker James Tubbs always went to hisworkshop on Sundays to test the sticks he had benton the preceding Saturday, thus avoiding surpriseson Monday!

With regard to the hair tension, it should be notedthat the climate may play a confusing role. Hairsare very hygroscopic and in humid and warmsurroundings they may absorb water and stretch afew millimeters. It is known that in a humidtropical climate players sometimes cannot wind uptheir bows enough because the screw mechanism

has reached its end before there is adequate hairtension.

Taking a gun barrel view from the handle to thehead of a bow, it can be established whether thestick (apart from the camber) follows a straightcourse, and whether there are any irregularities inits thickness. In contrast to what many playersthink, this course is not always straight; some lateraldeviation to the left for a violin or viola bow and tothe right for a cello or bass bow (i.e. contrary to thedirection in which force is exerted in playing) isfavourable. Many quality bows are delivered thisway, the bending being done after setting thecamber. The lateral deviations just mentioned(when in the right direction) make the “feel” of abow somewhat stronger; there are however alsogood bows which are totally straight, apart from thecamber. A lateral deviation in the wrong directionhowever should always be corrected.

All this bending - adjustment - of bow sticks is thework of specialists and, if well performed, can havean amazing effect on the playing qualities of a bow.The suggestion of Rokos [70] to perform this athome on a rainy afternoon with a few heavy booksand a central heating radiator is not worthfollowing.

The wrapping which protects the stick from wearand tear, together with the leather thumb rest, givea more comfortable grip. Personal tastes play a rolehere: one may prefer a thinner or a thicker leather,and this may depend not only on the stick diameterbut also on the manner in which the bow is held.Old bows (especially those from French ateliers)had a wrapping of silvered thread; whalebonewrapping has also been used, especially on Englishbows, and leather. Whalebone wrapping is nolonger obtainable, but there is a quality plasticvariant of alternating yellow and black threads.Plain plastic is usually mounted on the cheaperbows. Many master bows now have a silverwrapping, which (by varying the length of thewrapping or the thickness of the wire) enables acertain adjustment of the balance of the bow (see7.5).

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In choosing a bow, many players will consider the“feel” of the bow to be an important element, andnot so much the weight, strength or balance.According to W.C. Retford, who worked for morethan half a century in the bow workshop of Hilland Sons in London [72], this is not so bad anapproach at all. In his book “Bows and bowmakers” dating from 1964 [63] he has made a fewsensible remarks about choosing a bow. Theseremarks, quoted below, remain valuable even afternearly forty years. The only remark to be made onthese lines in the present time is that the sound ofa bow has received little attention.

“When choosing a bow the selection should befrom a number varying in weight, strength, etc.Attempts by a salesman to influence judgementshould be discouraged. There may be instanceswhere it might be well to have the opinion ofanother, but beware of the crank. The rule could be:if you dislike a bow, don't buy it. Dislike entailsunhappiness, a prime factor of succes will bemissing. For one who cannot play, the choice mustbe the teacher's. For the player it should be entirelypersonal; the bow should feel a part of him, ascomfortable and unobtrusive as old clothes to anold man who is contemptuous of fashion.

“Buy the best you can afford. Do not buy forthe name. The possession of a Tourte will notprovide a passport to fame.

“Gold is a better metal than silver. Silver isbetter than cheap, low carat gold. Many goldmounts have heavy, strong and unresponsive sticksscarcely providing the ideal combination with thesensitive Cremona.

“Do not make a hurried decision. We get thefiddle out; things don't go well; we put it away. Aswith the fighter who retreats, there may be anotherday when things go better and judgement may bemore balanced.

“When buying an old bow a problem may arise.The practice, usually, is to take a gun barrel view;frequently, if the stick is not straight it will becondemned, a bargain may be lost. It may not beknown, the straight line of the stick is artificiallyproduced and skill can, without difficulty, restoreits gun barrel accuracy.” [63]

7.5 Bow, instrument and player: a triad

After the general aspects dealt with above, a moredetailed description will be given of the factorsdetermining the properties of a bow: balance,weight, strength and elasticity.

Balance

The point of balance (the place where both halvesof the complete bow have the same weight) is ofutmost importance for the playing characteristics ofa bow: if it is too close to the head, then playingnear the frog is difficult: a player who is not awareof this will call it a heavy bow (and may reject it).On the other hand, a balance point too near thefrog is also not pleasant, as such a bow has too littlemass in its upper part, comes easily off the stringand is therefore rejected as too light. One can getan impression of the balance of a bow by holding itin playing position and moving it around; it isbetter to measure this exactly. This is very simpleand can be compared to the verification of “light”and “heavy” by weighing the bow on a letter scale,see fig.7.6.

According to Wunderlich [92] the following valuesare recommended for an optimal balance point inan average situation:violin and viola: 24-25 cm from the end of thewooden shaftcello: 23-24 cm For double bass it is very variable, especially in viewof the two types with high or low nut.

Sometimes the values for the balance point aregiven in cm from the thumb grip [82], but this isless accurate because the length and position of thismay vary. It should be noted that the figures givenabove refer to a standard situation; some playersprefer a bow that is somewhat top-heavy,corresponding to a balance point of, say, 26 cm fora violin bow.

The question may be raised whether all thesedetails make sense, as one could say “good is good”and “bad is bad”. The answer is quite simple: an

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Fig. 7.6 A cello bow placed on a simple device to determine the balance point. It consists of a ruler with divisions,onto which on the place of the 0 an old violin bridge with a cut-away at the upper border is glued as a support, (anotherobject instead of a bridge will do, of course)

optimal balance obviously does not increase thequality of a bow, but brings out its potential inplaying. Many players complain about the qualityof their bow, and something indeed might bewrong with it; often its adjustment is not optimaland its hidden qualities not revealed. On the otherhand, there are thousands of well-balanced bowsbut which are totally uninteresting for the player.

One may change the balance of a bow e.g. bylengthening or reducing the silver wrapping or byusing thicker or thinner silver thread. Such anintervention obviously influences the total weight ofthe bow and sometimes one has to compromise toreach an optimal solution. If it proves impossible toobtain a satisfactory balance due to insufficientweight of the head and the bow is sufficientlystrong, it is sometimes possible to insert a smallpiece of lead in the cavity of the head if there isenough room. Some experts consider this as anunethical intervention, but nobody has difficulty inchanging the wrapping for balance adjustment.

When the tension on the hairs is increased byturning the screw button, the frog approaches thehead slightly. Even if this amounts to no more thanhalf a centimeter it will affect the balance. From1836 the versatile J.B. Vuillaume produced bows inhis atelier with a fixed hollow frog with a piece ofcopper inside to which was attached the hank ofhair. This piece was moved up and down in the slotthrough the action of a turning screw as in a normalbow [47a]. The specially-prepared hair ribbon withblocks at both ends was fixed in the head througha side opening; the other end was fixed inside thenut after taking off the pearl slide. The player couldthus rehair his own bow without the need of aviolin maker. The hanks were sold in small round

boxes in the Vuillaume violin shop. In spite of theevident advantages of this system, it has notsurvived. These so-called self-rehairing bows fromthe Vuillaume atelier were made from quality woodby the best bow makers and they have later beenconverted to conventional bows (as by filling thehole in the head and replacement of the frog) andare used as such to the present day.

Weight

The notions ‘heavy’ and ‘light’ are often usedcarelessly by players. The reason for this, asexplained before, is that the feel of the bow in thehand of a player may give a false impression ofweight because of imbalance. This discussion canbe cut short by weighing the bow: a letter scale willdo; its electronic version is not necessarily better,although it can be read more precisely. Thestandard weights and ranges are given in Table 7.1.It should be emphasized that the importance ofbow weight is often overestimated; except inextreme cases the balance is more important thanthe weight per se. Recently, there has been atendency, to use slightly heavier bows; this is probably related to an increase in the use of stringswith a core made from a synthetic material (chapter9) which have a greater stiffness and require a somewhat heavier bow for ease in initiating a stableHelmholtz vibration pattern. Many splendid bowsfrom the 19th century are now being laid aside because of insufficient mass; nothing can be doneabout this. Nor is too heavy a bow (assuming thatany excess weight of silver etc. has been removed)easy to repair either. Weight reduction throughshaving will also affect the strength of the bow.That this is a risky operation is illustrated by an event told by Wunderlich [92]. Near the end of the

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19th century the Berlin violin maker Riechers hada beautiful Tourte bow which he had given on trialto the violinist Joachim. Although Joachim admiredthe bow for its tone, it was a little too heavy in hisopinion. Riechers then worked on the shaftreducing its weight and presented it again toJoachim. To the astonishment of both, the bowappeared to have lost all its strength and elasticityand could barely be used. Such work with a knifeand file on a priceless Tourte bow would nowadaysbe unthinkable, but in the 19th century there wasless restraint in improving antique master works. Inthat period scores of violins and celli of the greatmasters have been made smaller or larger at acustomer’s request.

Strength and elasticity

Weight is, up to a point, independent of strength (=resistance to bending). A bow can be light andstrong, or vice versa, namely heavy and weak. It ispossible to measure the resistance to bending understandard weights with an instrument, but this is lesssimple than determining the weight or the balancepoint. It is best tested by feeling the flexuralstrength with two hands, with the thumbsopposing inwards; an opinion of some value canonly be given after extensive experience with varioussticks. Fear of breaking the shaft is generallyunfounded. Pressing the point of the bow on asurface to test the resistance (as is often done) is notto be recommended: in so doing the pressure isconcentrated on the foremost part of the tip of thehead plate (fig.7.3) and damage to it is far fromimaginary. In many old bows the foremost part ofthis tip has been broken off (though not necessarilyin this manner).The bowmaker can restore this,with the support of a new plate. The advantage ofsilver head plates is that they are usually strongerthan the very thin ivory plates of the classic Frenchschool.

Traditionally, strong sticks are often mounted ingold; however a strong stick is not always preferredby the player. A weak bow with low resistance cansometimes produce a beautiful tone; in certainvigorous passages more resistance is required and

then they fail. The famous English bow makerJames Tubbs produced around 1880 a number ofvery weak “whippy” sticks, which appear now andthen at auctions. They were probably made for theLondon happy few, where amateur music makingwas a favourite past-time, the whippy sticks helpingto produce a beautiful tone, difficult passages beingsimply avoided. Tubbs also produced muchstronger sticks for the professional musicians. Aweak bow, lacking in hair tension, cannot beimproved by further tightening by the screwmechanism, nor by restoration of the camber whichwould increase the amount of spring [63].

Elasticity, up to a point independent of strength,can be defined as the way a stick returns to itsoriginal state after bending. This is a property ofthe fibers in the wood [21a]. Elasticity may seema good thing but excess of elasticity can make a bowtoo nervous.

Bows should be kept in the violin case withloosened hair tension, primarily for relieving thepull on the head; this is a considerable force which -according to the strength of the stick - may varybetween 5 and 8 kilograms. Most players wind upany bow in the same way and this is often toomuch, perhaps because they once started with aweak bow. When the tension is tightened to thepoint of pulling the stick into a straight line, or “outof camber,” many strong bows perform poorly andmost bows become laterally unsteady. A generalrule is to wind up a bow until the distance betweenthe belly of the stick and the hair ribbon is aboutthe same as the thickness of the shaft in the middle[61]. A strong bow may need less tension, a weakbow more, depending on the bow strokes in thepiece to be played.