November 1 9 1965 NEWSLETTER MO. 4 THE CATCHUP ACOUSTICAL SOCIETY As announced in the last issue,, a concert was «ivan at thn vw vm« in New York City on.. May 20,1965 at. whi* the S/vioJin "~" all eight members was presented toj public^ r,"*>"tfa^iD%««-_-, "Consort the The for True Violins",,— compose d^anf^^ed by The music gave each of the instruments a real, HenlHr^t their work-out, cSISL musical potential in various combinations of parts a^d fSfm^from solo, duo, and trio to a thick texture of the entiri oatet? B 00t f lhe"fffS? ne'w^^iSfeed^?!!.^:^ -" ° **«»"« %&£*£*£ Leopold Stokowski was in the large audience, and was del igbtS'd He told Louis Condax that he would never forget the sound of thf viola in
The New York Times' Howard Klein quoted Maestro Stokowski ?s "We need to revise all. the orchestral instruments. The strings have needed this treatment for a long time. Now the woodwinds nS! -1 Z _LXi^ o motIL- In his review of May 21 „ 1.Q65,. Mr. Klein went on to say- "The produced wonderful and rumblings, the sonorities of. the Mgher viol fes re m high registers. The resonance of the c.foodTh p .food middle rln^e lis M lnst ent3 > whe paying their lowest notes, soundfd tiLT or¥?J£&nasal, so "there is workf to be done. But a the major step toward rwSvat'n* strings for the first time in 200 years has been tLen?!f aSi bravo^ msiola 8 who Vl^* «» new weref * __ instruments in their premiere concert Max Pollikoff Treble vjolin Lrnestine Briemeister Soprano violin Lllla Ealman — Mezzo violin lll^L^yf —- (vertical viola) Peter Rosenfeld TenorA"?.^?violinl^ Joseph Tekula Baritone violin David Walter Bass violin Stuart Sankey G ontrabass viol in Many members of the Catgut Acoustical Sooiaty, who shared m the have actually work of developing these instruments over the past sev-n years, were in the audience. Interested musicians came from far and near One violinist, Marie Bond Riggenbach, flew all the way m from her home Monte Vista,^Colorado,^especially for the concert. We have received a great deal of other publicity as up-to-date well . To brino- what was reported in the last Newsletter % (1) Carleen Hutchins spoke to the Acoustical Society of America at its June meeting in Washington, B.C. This included a presentation new family of the of eight instruments. These were judged of particular inter- est to this group because they represent the first time in history t*at a consistent theory of acoustics has been successfully applied to a whole family of musical instruments,,
ha-^, 2 (2) Publication in the American String Teacher of* (a) "The Catgut Acoustical Society Involved in Improving Stringed Instruments", Spring 19.65, John Schelleng (bj "The New Violin Family", Spring 1965,, Carleen Hutchins (c) "Three Firsts for the New Violin Family", Summer 1965, o. Hutchins (d) "The Hazards of Weather on the Violin", Fall 1965,Robert Fryxell (3) The Princeton University Press has expressed interest in a publish- ing program which would include (a) the original writings of Savart with translations by Donald Fletcher (as discussed in Newsletter N0.2) (b) Frederick Saunders published papers, and (c) other research, papers in this field. In addition they are interested in a book on violin research which would encompass all of the efforts of our Society members. John Schelleng and Carleen Hutchins are already involved in a start on this project. (4) Heinrich Roth, of Scherl Roth in Cleveland,, has already arranged to have six vertical violas made from Maxwell Kimball's drawings in the Roth shops in Germany. These are to be finished except for plate tuning, which will be done by Carleen Hutchins. As this is being written, she has just received the first instrument from. Mr. Roth. With all of this expanding activity and publicity, it is clear that we, as the Catgut Acoustical Society, both individually and collectively, are making our mark on the musical world. This brings with it an increasing responsibility which 'requires added efforts on the part of all of us, both in time and in financial, resources. As one example, previous Newsletters have been published in quantities of 150, nearly three times the number needed to satisfy our current membership; yet almost all copies have been sent out to others who have expressed interest and who are in a position to aid in furthering our objectives. The present issue will be published in a quantity of 250 in anticipation of the increasing number of interested musicians and scientists. Since we are "getting known",, your Executive Committee has drawn up the following "Requirements for Membership" with no intent to destroy our informal nature, but merely to codify what we believe is a reason- able minimum of regulations a sort of thing which any organization must have as it grows. This —statement, together with "Aims of the Catgut Acoustical Society" published in the last Newsletter, constitute our charter and is the information which will, be sent out to any who express interest in our activities. REQUIREMENTS FOR MEMBERSHIP To be eligible for membership in the Catgut Acoustical Society, a candidate must subscribe to the aims of the Society, as set forth in Newsletter N0.3, and express tangible interest therein. Suitable expression of such active interest may be either direct aid in carrying out musical and technical projects or a monetary contribution towards defraying expenses of printing, postage,, etc. Although both types of support are equally valued, and although there are no official dues,, it is hoped that members will find it possible to share in the latter way, if only modestly. Names will be removed from the membership list after three years of complete inactivity. This requirement goes into effect with this issue of the Newsletter and is not retroactive. Any member may sponsor a candidate for membership by sending name, address and qualifications to the Secretary: Carleen Hutchins, 112 Essex Avenue, Montclair, New Jersey. A list of proposed members will be y within six months of publication! ln good ate^i*S 8 he b< e ~ newsletterNewsletter are y1 «£^ ? T S li7t7d~"in the" last" b^« hereby elected to membership. They are- 11 Road Dr'Earll ?"£SJ» iVS"* New JerseyV «rpS^ , 00m Slkhart, Indiana 1 ll1 ?AMa i^" - nolia SrWT^!!" £ S Lane, Princeton, New "JerseyJersey , Dr. W. Lottermoser,' Braunschweig, Germany
N V'Y riS/f^ 8011 111 Washingtol ' ' ' ' 2"WE laH^'^S aSL^*^Stitute of Cleveland, Ohio d Si?g? SS*? K&* $£» ont 2tS°i wM^ Sanitorium;London,Ont.- W a (in I le to'carl^Hutchins)^"! Sa krison t?ef SHd*' °°*oerts""-^in (State Washington last spring and on these *""" ° of) on the eacA of t^I ed a group of pieces viola*. I demonstrated ??»?+£»,c Conference at Educators National PortllSd in f^?i Mvl,o .^sic oom (Robert Whitcomb) hM written P^er-in-re Sidence and piano which { a'bXtif^ T* 1 01 n&^gS^^Tg^lay> falls m love with this v-ini^ t d iw ! P the audience* prod^e some. iS going to I oouid sell a hundred^? thefm Th ubll teaohers see at once the value nf * t P school music ?hs = ! 0 ment, and they would ° 11 instru" l^to have fplrt orcne stras. p q „„,„„! oS^raf AsL^"soon*as* violas are availahl t 8 t0 *Starti 8 the school « " 0US a West Coast olas s for public (inst^ttoS. A o e " 01 made by a ?" 7 R.Parramon of Barcelonaa rre-strung L 7=i i R^ (vertioal viola) ?g!£« "i" SMJS" ' Ced I
T 6 fo lowin new S candidates are proposed for membership (ni} M i B rt 989 Memorial Drive, OxbridgecUUOXIa e MassJttass. On^^wContributedl^valuablef i?^»editorial assistance = » (2) Dr.Bernard 605 National Amateur. pickstein, Building, Flint I,ilChlsanMiahi«n' violinist and string instrument enthusiast
Bassist,- helping to demonstrate the new instruments (4) Miss Mar jorie.Bram, 332 Vose Avenue, South Oran-e New Ter-^v
Music", a group performing on a consort of viols V (5) and Mr. Mrs. Quincy Porter, Holderness, New Hampshire Composer, violinist, violist (6) Mr. David Schwartz, 26 Gurley Road, Stamford, Conn Violist, Yale School of Music
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■ 4 (7) ß P N Dyer II The L.C.L. C0rp., Park Interestedpr 230 Avenue, N.Y.C, !l°i ?in the new violin family; active in supporting following its progress. IIS andana (8) uthier Lodge", l46l. Rosecrans, Violinist,,Vi;i?S?3 violin San Diego 6, Cal. maker,, and president of Southeri Californiaoainornia Association of Violin Makers.
TREASURERS REPORT: Balance reported in Newsletter N0.2 as of 9/20/64. $120.10 Four contributions 150.00 #2*70.10 Expenditures: Reprints, "Physics of the Violin" $20.00 Postage 25.00 Newsletter expenses 33! 00 Photographs for Newsletter lo.'oo Bank service charge, l2 months 8.60 YMHA Concert 5/20/65 82 6$ 179.22 Balance, 9/20/65 o "We are * 0 30 happy to record the anonymous gift of $100.00 from one ent v ia t:LO a*>°ut the advancement of of stringeda i^ £ ? S research in the family instruments. It is very likely that with the increatin- interest in the new instruments costs that will also increase # the requests for Newsletters far AlsS exceeds that of the memberb! Until' such a time as a grant will provide these costs, donations are sought from our earnestly members. There are no dues. May I urse that yyou contribute to this undisputedly worthy cause." * Sincerely, Virginia Apgar, Treasurer. 30 Engle Street Tenafly, New Jersey
As promised m the last Newsletter, this issue will present contributions from members which we hope you will find and both interesting instructive. First, however,, youreditor offers a brief historical article describing the life and work of the late Fred„L. Dautrich! ic is the intent that future Newsletters will occasionally include similar items. ' 5 A CHAPTER IN THE HISTORY OF THE VIOLIN FAMILY
Lack in the 16th century, when viols were in their heyday, the need and desire for instruments with bigger tone and greater flexibility in tone color led to the gradual evolution of the violin family. We now have the violin, viola and cello as the popular instruments, and correspondingly, the viols have long since fallen into relative disuse. Hoy/ever at several times since the violin family emerged, there have been serious attempts to enlarge the violin family in order to combine the versatility of range of -uhe viols and the versatility of tone color of the violin.
The first such proposal was described by M. Praetorius in his SYNTAGMA MUSICUM: DE ORGANOGRAPHY published in 1619. Later, others including Savart and Vuillaume also addressed themselves to this problem. In recent times, Dautrich and Hutchins each successfully designed and produced an enlarged series of violin-type instruments. Of the Hutchins instruments, we are currently witnessing their introduction to the musical world, as we have reported in past newsletters. A history of these developments needs writing. It is intended that these newsletters provide the medium for recording all available information, first as a matter of interest to our readers, and second, as a basis for a subseq uent larger article for broader circulation. To start off, this issue will tell the story of Fred L. Dautrich. Your editor expresses his great appreciation to Mrs. Jean L. Dautrich for the loan of countless brochures and newspaper clippings from her family archives and for much additional personal help and information. First, the man. Fred L. Dautrich was born in Schlierbach bei ,7&chtersbach, near Frankfort am Main in Germany, the youngest of twelve children in a family of artists and artisans. At the age of twelve he ".vent to Frankfort and worked as an apprentice at cabinet making until he was seventeen. Since he was an ardent pacifist, he left Germany at this age to avoid military service. Together with a sister, he came to the United States and settled in Connecticut, where three brothers had preceded him. For. a while, he held various jobs and studied art for which he had a great talent. But after a year and a half, he had a breakdown which necessitated a complete change. He went West and thus started a series of moves and travels which. took him tomany oarts of his .adopted country. Most significant was his acq uaintance with Mrs. Delia Burnham of Orange, California, fur whom he worked as a gardener. Kfcen she discovered his talent as a painter, she insisted that he attend art school. This he did, in the art department of Colorado College in Colorado Springs until her death, and later at the School of Art and Design in Los Angeles, thus carrying out her wishes with the money she had left him. Through these years his interest in music grew, and with his ability as a cabinet maker, he became proficient in repairing and re-graduating old violins. He returned East, to Huntington, West Virginia, where he became director of a church choir. Here he married and soon the illness of his wife again took him West, to California, thence to Idaho, and eventually to Tacoma, Washington. It was here that his plan took shape for enlarging the violin family. Two new instruments were finished and "uried out here, and they received a very favorable reception. He later returned to Torrington, Connecticut, where during the 1920' s and 1930' s he continued his studies and experiments with violin-type instruments, ar. work which culminated in a family including three new
' Vilon, sizes of instruments. Two of these he called the Vilonia and which are designed to play alto and tenor parts; the third is tne Vilono which in size lies between the cello and bass viol. 's The following notes on the instruments are given in Mr . Dautrich "Bridging the Gaps m the own words, and are extracted from his brochure Violin Family" (1935) his article "Three New I and strume^"^ rNT o T Violin Family" which appeared in the October 1935 "issue of THEf^^VIOLiNIoT (pages 12-13;. Viols the perfection of the violin type of instrument, the "Before use, were the most practical form of bowed stringed instruments in bass. v 40..4 0. ranging from those smaller than a violin to the size of the . size were used Chests of these viols, usually consisting of one of each in the fourteenth and fifteenth centuries. difficulty of their peculiarities of tone and tuning and the "Because favor, and of playing caused by the many strings used, the viols lost of the instruments of the violin family increased. Ao finer the use disappeared xrom use. violins and cellos were made," the viols practically family, "The more practical tuning of the instruments of the violin strings tuned' in fifths, offered a new field for both musician using four could be written and composers. More difficult and more beautiful music played of the violin family. String quartets and on instruments instrument consisted of two violins, one viola and one cello, and these were used as the foundation of symphony orchestras. cf "Although the violin and the cello reached their present state over 200 years ago, the viola has not been so rortunate. perfection satisfactory tone it is When made large enough to produce a fairly Impossible to play It under the chin, and when made smaUei, almost very much lika. barely larger than a violin, the quality of tone is that produced on a reasonably good half -sized violin. music, string ensemble and orches bra music , the "In modern chamber leading par.. first violin, which is a soprano instrument, takes the playing the alto part, although It Next comes the second violin thereforeJ- in size and tuning with the first violin, and must identical tone of be a soprano Instrument incapable of producing a ti^_alto quality. for Its "The tenor parts are taken by the viola, under-sized even alto, and yet it is expected to play the tenor parts. tuning, which is by mo c No what the viola is given to play. It can never matter £art above tne cello. than an under-sfeid alto instrument, tuned an octave It should be made and tuned tx Where then is the tenoF"instrument? up t. place between' the viola and the cello, moving the viola taKTTEs But the viola Is .oo the alto part, in place of the second violin. take proper for its pi cm. small even for alto, and should be made the size a bass "Composers, players and conductors have long wished for tone and greater possibilities instrument having a finer tuned viol. Such an instrument should be mace and t^an the bass gap now exists between the cello the bass viol to fill the that 8 and most "THE FIRST VIOLIN takes the first part in string ensemble Much playing is done on the & orchestrations. instrument, its range shou.d be ule^^^nudeu most from an entire " _l- the ensemble, it is no*r possioit t-h« vilonia vilon, and vilono in the J^f entire range as we use no he toS the best use of its violin; instead we use a true alto instrument " second first, which is aop.snc; violin be alto when.it is tuned like the s^4^f
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■ 7 "THE VILONIA, a true alto instrument, is tuned like the ordinary viola, but it has the proper proportions for this tuning. The viola has never been so proportioned, which accounts for it peculiarities of tone. If the viola were tuned correctly for its size, it would be only one or two tones lower than the violin. Makers of other musical instruments have long ago proportioned their instruments for the tones to be produced; but of the violin family, only the violin and cello have been so proportioned. "My vilonia is played between the knees in the manner of the cello, with the cello method of fingering. Many people claim that it js av/kward to play an instrument between the knees; but where is there a violinist who does not remember his first attempts to hold the violin? Does the cellist seem handicapped by the position of his instrument? As a solo instrument, especially for ladies, the vilonia fills a long felt need. It is tuned in fifths, C,G,D,A, one octane higher than the cello. This gap of one octave is quite large, so I use a true tenor instrument. (Can the viola be tenor when it is but a few tones below the violin, the soprano, and an octave higher than the cello?),, "THE VILON, the true tenor instrument, is made to fill the gap of one octave between the vilonia and the cello. It is tuned GDAE, one octave below the violin, a fifth higher tha n the cello and is correctly proportioned .for this tuning, the tone being full and rounds The cello method of fingering is also used on this instrument, which is played between the knees. The use of the vilon will produce effects that cannot be obtained on any other instrument. "THE CELLO is the bass instrument of the string quartet and is correctly proportioned, well known to all as an ensemble, orchestra, and solo instrument. This instrument is tuned C,G,D, A^ with a full and pleasing tone of considerable power. In some forms of music, it is necessary for the cellist to play very high on the A string in an attempt to fill the large gap between the cello and the higher stringed instruments. With my Vilon in the ensemble, such gymnastics may be dispensed with. "To my ear, there is. a great difference between the tone of the cello and the bass viol. To fill this space I have made another new instrumen t4- THE VILONO is the new bass, to be used in quintet and all other forms of music where this type of tone is desired. It is tuned G,D,A,E, two octaves below the violin, one octave below the vilon, and a fourth below the cello. The cello- method of fingering is used on this instrument. The tone is much more pleasing for quintet than that of £he common "bull fiddle", having more of the smoothness and roundness of the cello. For solo work, the vilono is of course less flexible than the cello. But an able player can play solos that would be impossible on the bass viol. "THE BASS VIOL is tuned in fifths C,G,D,A, one octave below the cello instead of in fourths as done at present. This gives the bass a range eg ual to that of the other members of the violin family. A fifth string, a C string, has been added in some cases, but this seems nine ce ssary. " The above quotation from Mr. llautrich does not exjjlicitiy say so, but the series of instruments was based on the principle that all dimensions should be in strict proportion to the tonal range of the instrument. The violin -as we know it is the only instrument for which dimensions are traditionally standardized, for example, a body length of 14 inches. The viola and cello are more variable, having been subjected to a great deal more experimentation in an attempt to arrive GEOMETRICAL SQALIN& FACTORS
The outer pair of lines represents body length; the others, going inwards,, represent width of lower bout,, width, of upper bout,, width of 0 bout,, and height of ribs. at the optimum desired quality. The viola,, in particular,, has been the victim of such variability since in. addition to the matter of its acoustical worth,, there has been the need for a compromise with ease of playing,, i.e. a smaller size. Mr. Dautrich as we have seen adopted the premise that the violin and cello (of. average size) are correctly proportioned. On this basis he constructed a diagram, which we have reproduced, relating dimensions and tonal range. Note how far out of line the conventional viola is for its range. This diagram shows by interpolation the dimensions which he actually used in constructing the vilonia,.. vilon,, and vilono. We have also reproduced a
8 drawing showing these instruments, together with the violin, violoncello and bass viol. Clearly, the differences in proportions are more regular' than m trie usual series, shwn for comparison. The question of proper graduations for the tops and backs is one where we have about no information mr. Dautrich's methods. Presumably it was his skill as a maker and violin his intuition which made these instruments as successful as they turned out to be. Later acoustical research has shed light on the problems considerable of plate graduations, and this topic will he covered in a subsequent contribution to this history This story would not be complete without mention of the actual use oi these instruments. The "Fred L. Dautrich Quintet" gave a dozen or ,iore performances beginning in 1933, including appearances at the Juill School of music, Carnegie Hall (before the National ° and Orchestral Society) various music clubs in Connecticut. Reviews were invariably favorable, and it Js indeed unfortunate that limited funding and publicity caused _ these instruments to disappear from the musical scene for"a long time. Carleen H utchins in recent years acq uired a set from of these instruments the Dautrich estate and their reappearance will be described in another issue. X is a , }. Pl to present a photograph of the Quintet by n .° n f ea^re taken Karl Gall about 1933 which shows Fred L. Dautrich (standing) and the following performers: William Beach, violin Helene Halabe (Mrs. Jean L. Dautrich), vilonia Raymond Green, vilono Jean L Dautrich, cello William Khoury, vilon
Thanks are due Douglas Ogawa for his cooperation, and his skill m making such excellent copies of this photograph from an yellowed print. old
POSSIBLE EFFECTS OF SHEAR IN BRINGING VIOLIN PLATES TO OPTIMUM CONDITION — Carleen Hutchir.s As a top or back plate is thinned to final dimensions and checked at intervals in the process by the tap tone test, it is possible to watch on the oscilloscope the changes in ho.th the amplitude and frequency of the main resonances. The closer the plate comes to the standards of good violin making practice (which I have learned from. F Sacconi and Karl Berger) the greater is the amplitude of the resonances and the more numerous. (Lottermoser at the German Bureau of Standards, who is working with their violin industry, also reports this). This feature is particularly noticeable when shaping a bass bar after it is glued into the top plate. If one shaves off even a bit too much wood, there appears a sharp drop in peak amplitudes. In other words, the condition of optimum RING- or. response of each plate, so precious to violin makers, can actually be checked on the as dllo scope as a plate is brought to optimum dimensions. Eugen Skudrzyk (physicist,Perm* State) thinks that this phenomenon is directly related to shear factors in the wood. He, John Schelleng, and I plan further experimental studies in an attempt to understand this behavior.
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Q BACK AHL BELLY CLAMPS Gordon. McDonald got interested— men I first °3xlo ny first jots was the makMJg;i*/^of a »*t o~ J^oapa^ mating and others have x the £mtrihuted many good ideas* f*g*W$ i££ ßt,% which and use of this type of a* u^,Sf of years,. this revie.<*^P-w of ideas*** in L tadwds aas occasioned * ««« Soots and%ven. the spool type clamp has beezLUSsa.£c jis "J^^d- Osa Mate a e^^^ SiSliuS! rS^atg»^^^»®SSn« mlgh^ he as f0 «4 easy to apply l"cIaiPs should M small,, light, *tUk
?«J£f;>ji"J,chances oi breaking,.^rp^e^at^eoSerf^teww auco 5.Jlt^e\-*ro Should minimize ~ S he^ex^littl, open space between the pressure pads of * ?Se "fshoSf with pi a*, eagws o.btee.„ uuj.w orux screws in contact vw hPttpr 8 bolts stratus, but *""Jprobably better is not as 1lively to fftrse it^s Brass a^^*X~7^>be \oneYii ui^ao.mltaL screwsso. and the to eliminate any possible contac-c umen r accessibility for removing, excess glue. 0 TherHhous.d bo good i6. These clamps should lie easy to make. -,--„> p is shown by i c,.r* -^ txe-t-v. a,o ,c. -. *he proposed clamp to take 0.. q^i- e©r. Some comments on the or the sketches. tt -luuu and"ana a newiuw type with rough check of a spool ©lamp with**"*W^tfa ± 1 A - w rax indicated. piu«.oa-.tJ uu u.^ <* o i n ?4. a^rew. both viola aa, were |4^J 2i? pounds per >«>_» inch. Both had.wir,g. jnw*i* what felt lilca a tllhwS to reasonable ..ft wxirowow„ Thelf square inch is
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Q-fo.vre 11
10-24 screw clearance to keep pressure off edge
sufficient width to accommodate curvature of pads.
clearance hole #12 drill. Other end #28 drill and 10-24 tap A - 3/4 of thickness of edge of plate -hthickness of neoprene B - clearance -f- pad width -f- allowance for pad curvature
cross-section
lower bouts, about 2/3 of upper and vary degree of total number lower bouts. curvature of of clamps. pads, also width of blocks. for blocks used at X = overhang of plates over ribs corners, chisel off excess wood outside pads.
>BaiIkIHAKY STUDIES Otf VIOLIN &JJUi!ott PATTYS - Stewart Hegeman i nd Garleen Hutchins We have applied a loudspeaker technique to testing an instrument tsing a wide band excitation and omnidirectional piokup. Exploratory ;ests indicated that controlled procedures of this sort might gilzse ■aluable information on instrument performance. Preliminary observations show that violins and violas which were properly balanced for plate ;ap -uones were nearly omnidirectional in"radiation; while those known ;o have improper tap tone relationships were nearly unidirectional, dth radiation coming primarily from their tops.
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RESPONSE OP A PLATE IK THE REGION, OP UNRESOLVED RESONANCES, AS AFFECTED BY DAMPINGr Arthur H. Benade Consider a violin plate— as a two-dimensional wave carrying medium with defined boundary conditions. (These may be "free* or "fixed" or even "mixed",, but without too many constraints that are applied away from its bounding judges.) I£ this plate is excited at some point by means of a- rarrts^ie -fre quency constant-force driver., and if the amplitude response is observed at some other point by some sort of detector,, it. is possible to otitaiii- a frequency response which will show peaks; and dips that are controlled by the nature of the reson- ances of th© system' and b# the positions of the driver and pickup. At low frequencies- only a few widely-spaced resonances are found,, whose properties have been, extensively studied as a means for guiding the adjustment of violins. It is the intention of this note to call attention to the possibility of using; the statistical behavior of the higher-frequency resonances as a way of obtaining ani overall impression of the properties ofl' the wood used in. making the plate„ in particular the frequency dependence of the damping; of the wood. There are two motivations for proposing,- the method. First „ it can be used in a region or frequency where 'conventional resonance methods of measurement are difficult.; As a matter of fact it can work precisely because the resonances are poorly resolved 'at high frequencies,, but where it is possible' £o make statistical" statements about the average response. Second,, it appears that usefuS qualitative information can be obtained which does not depend much on the detailed shape of the plate, or (more particularly) oil the degree toward a set of proportions which are suited to the actual piece of wood, under consideration. At driving frequencies hig#i enough that the closely spaced resonance a (separated by an amount that is less tham the half-power band width g; of the individual resonances) are no longer resolved from one another,, we can write for the average response integrated over many resonances the following simple formula: Response « const, (l/d) 1 - (l/B).(g^j), ttd^p) of Eere, o> is the driving, frequencyft & is the half-power bandwidth- the resonances in the neighborhood ofa)„ and E(d,.p) is a. messy and uninter- esting, function, that depends om the particular positions of the driver and pickup. This function is irrelevant to our purposes because it merely causes fluctuations above and below the much smoother wiggliness of the true response function, the average of this being; represented by the remaining; parts of the formula. Let us now see what is the laboratory meaning; of this expression. A plot of the response measured in dedbels is expected to fall with, rising frequency at the rate of 6 dtr/octave iff the ratio {,&/<£) is constant If. (gA>)< gsows with, frequency,, then the response curve will fall more rapidly than 6 d£/octave„ the converse is true if (g/id); falls with, frequency. The point of the analysis may be put rather briefly. We have separated out the "obvious" (1/io) part of the response. This part of: the variation come 6 from the geometrical facts of life .pertaining, to any waves whatever. The remaining factor contains the interesting physics: it is the departures from (1/ij) behavior which tell about the special properties oi wood, in a manner which appears reasonably independent of the measurement technique and which requires only relative measurements. N
Thil pace dearly iltuitratea tbe Improvement* ol the new nystem over ihe
DAUTRICH
The sketch bel-ow will suggest the way in which experimental data can be plotted for convenient study.
Wiggly line due to unresolved resonances and the humpy
The presumption is that a smooth curve which is fitted to the upper frequency end of the ol*served response curve will ,serve as the "signature" particular for a kind and condition of wood. This curve would presumably re tain, its shape for any reasonable attempt at keeping the geometry the same from sample to sample. This is in marked contrast to the rigorous precautions- which must he. observed in the measurement off damping by means of isolated resonances. " The possible musical application of this result arises ffrom the fact that we 'have a way to see how the damping; of a given sample varies with frequency,, in a manner that is pretty much independent o£ other properties of the vibrating, system (wood,, driver,, pickup). If the general trend of the smoothed, line drawn through the higher-frequency part of the response curve for some particular component wood in a fiddle is characteristically steeper, less steep, or equally steep as a 6 db/octave line, then we have a possible way of quickly finding; out whether a new sample of wood is comparable and useful for making; this component. All that is required is to out a slab, of roughly the same size and shape as the original sample, and plot the response curve. One does not, have to worry about the details of the bumps in the curve, nor about their positions. It is only the overall trend that is important: is it or is it not of the same general char^cter^as that pf the original piece. It will of course take some experiment: to see whetftei: the differences between different kinds of wood ar# in fact sufficiently large for this test to be useful.
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lICROSCOPIC EXAMINATION OF WOOD Ellis Kellert Some time ago at a meeting, of several,research members of the Society, here was considerable discussion about the microscopy of the woods in Id violins. Apparently little is known, on. the subject and it was felt hat effort in this direction migfrt be fruitful. The writer agreed to nitiate an. investigation. It soon became apparent that although much had already been published n the microscopy of wood, all previous studies have been made on thin, .icrotome sections. Such techniques invariably involve chemical treatment: lxatives,., solvents,, and dehydrating agents. Feeling strongly that treat-' tent of this sort may destroy some of the features of interest, I consid- red an approach -that would obviate the use of all chemicals. In this .aimer it was hoped to reveal hitherto unknown cellular structures and ntercellular objects such as crystals that'might affect vibrations in he wood. This study began with the employment of thick cubes of wood the surfaces f which were highly polished,, cleaned and viewed in the microscope by cans of reflected light. It is quite surprising how clearly the cells nd other structures appear with magnification of lOx to lOOx; particu- ariy when a highly refractive liquid is placed on the surface under bservation. Preliminary studies indicated the practicality of the method, ittle new information has been derived as yet, but the study will be ontinued and other light sources such as ultraviolet light and fluor- scent methods will be employed. **'■'
URTHER STUDIES OF "MOISTURE BREATHING" BY WOOD — Robert Fryxell In Newsletter #2 (Nav„l964^ I discussed "moisture breathing" by wood, .nd the effect and possible consequences on a violin in terms of a shift .n the tap tone, and perhaps even a significant amount of adverse de-tuning" of the top and back plates. John Schelleng, points out that ;he total effect may be even more severe than these results indicated since the frequency measurements were only in. the with-grain direction- :ross-grain changes are known, to be considerably greater. Others have pointed out some additional consequences which may result "rom such weight changes^g^ example ,; the amplitude of a resonance peak Lay be depressed and damping, may be increased if: the weight shifts either ay from what it was when the plate was (properly) graduated. These two ;henomena are collectively known to the violin maker as "ring" and he is cry aware how sensitive the proper "ring" is to graduations. In other ■ords, it is reasonable to expect that a change in weight by moisture reathing - is detrimental in the same sense as is poor graduations.- My previous report (subsequently published in THE STRAD,Feb. I96S in n enlarged version, copy enclosed) was based on studies of small rectang- lar bars of wood. Such a shape and size made it much easier to handle arge numbers of samples, and resonance frequency measurements also were impler and more reliable than with actual plates. I have since made a cries of weight change measurements with 17/ actual plates, under con- itions ranging from dry indooj* winter heat to 100$ relative humidity ail at normal temperatures frSn 7..0-80 ft). The^gJ^gß.H. tests involved uspending the plates in a five gallon, sealed container which contained . tray of water in the bottom. Periodically the plates were removed riefly for weighing. ■ The -results can be summarized as follows: maple and spruce in the white, the difference in weights was 1. For both Moderately as high as 8# between dry indoor heat (February) and 100# R.H. humid August weather was in between, somewhat closer to the. 100^ R.H. condition. There was no significant difference between the two species nor was there any relation to age which ranged from 4 to over 100 years. 2. Three coated plates were tested alohg with the above and showed only about 3/4 the capacity fbr moisture "breathing as those in the white. rpVi q -fr ■ceorfi " (a) Carleen Hutchins spruce top, varnished 1948 hut no filler added. (b) Carleen Hutchins maple back, linseed oil applied 1953 out not. varnished. (c) Santus Serafin top* original varnish* early loth century. These three were strikingly consistent, and thus show, that agB in itself has not lessened the moisture breathing,. is a tremendous difference in the rates of' weights gain and weight 3 There from loss* for both in the white and varnished plates. When taken a very dry environment and placed, in the 100^ R.H. container* they showed very gradual weight gains and in fact were still changing slightly when the exposure was terminated after 1& weeks. On the other hand, removal from the container into ordinary room air (either dry winter heat or moderate summer wither) resulted in extremely rapid weight losses. Within a period erf say, 4to 10 hours,, the plates had arrived at the equilibrium weights for their environment. It would be instructive to relate this large difference in rates to the change in behavior of an instrument when moved from dry to htfmld surroundings and vice versa. other 4. A few of the plates were Viibla backri, in the white,, made from species of woods. Only one of each was available,, but tentatively it looks like cherry and sycamore have a lower capacity than maple for moisture breathing;, and teak and paduc still less^ dm OH. THE PHYSICAL EFFECTS OF VIOLIN VARNISH — John CU Schelleng This is a work report on a project. which has not gone very far in spite of considerable effort, but which may be of some interest because of the one significant result which has been. obtained. The aim has been, and continues to be,, to measure the physical properties of varnish which are important acoustically, and to correlate them with violin response. In his article published in the STRAD (mentioned above), R. E. Fryxell has pointedly commented on the customary neglect of these considerations with the strong emphasis placed on visual beauty. What as contrasted a most needs study is the questions Exactly what does varnishi do to violin acoustically? Aside from the indirect but important function of preservation of tone-, it is the elastic: and damping properties and the mass with which we are most concerned (some of these may prove to be negligible , of course). Excessive elastic stiffness could conceivably excessive harm the instrument by altering the tuning of wood resonances, damping by smothering the vibrations. It is difficult to see how yar- actually improve an instrument which has been optimally nishirS can unan- adjusted in the white, and as far as I know, scientific opinion is the belief that a good varnish is one that does no damage. imous in that a var- /imong violin makers also, the opinion is commonly expressed nished instrument never sounds quite as well as it did in the white, though the idea of a direct improvement often intrudes. an the violin The only measurements on varnish; that I have seen Literature are those of Meinel (Jour. Acoust. Soc. Amer. , vol. 29,r7„i9WJ "
15 He gives interesting curves showing a more or less linear increase of decrement with frequency, wood being the substrate. He found that a hard varnish gives a smaller increase of loss with rising frequency than a soft one. Not sufficient data are given to calculate Rw (see (3) below), and no mention is made of frequency change . The aim of my experiments has been to measure logarithmic decrement damping) and Young's modulus and also mass. To that end a substrate of glass has been used in the form of a strip about 16 x 1.5 x 0. 2 cm, supported non-rigidly at vibrational nodes and excited magnetically by a very small armature of soft iron glued at one end, the vibrations being picked up acoustically by a microphone close to the strip. Glass has been employed because of its mechanical stability, freedom from hygroscopic effects, and freedom from a tendency to absorb varnish. It is probable however that in the future I shall return to spruce using the cross-grain orientation. Both substrates have their advantages, of which more will be said later. Experimental result: The one measurement has used "Amber Oil Varnish" made hy E, Harris, "England, and kindly furnished by C. M. Hutchins. The conclusions are as follows. lo Damping produced by the varnish increased during the first several days after application. This increase was first noticeable at 5500 eps; the rise which occurred at 1100 eps put in its appearance a few days latei 2.Within the range from 400 to 5500 eps, the damping after a six month drying period was substantially independent of frequency. 3.0 If R is the mechanical resistance of a cube of the varnish (in the same condition as the film after six months drying), the imaginary component of Young's modulus is Rw = 2,2 x 10^ dynes per cm 2. ( w = 2nf x frequency). 4oThe real component of "Young's modulus was too small as compared with that of glass to produce a measureable change in frequency. This will probably not be true when wood is used instead of glass. soUsing5 o Using data of this sort,, it is possible to estimate roughly what the effect would be if the varnish were applied to a typical violin. In an earlier memorandum I have estimated the losses in a violin in the white which result from (a) the internal friction in spruce and maple, and (b) radiation resistance. Using the same admittedly crude method,, we may now add the effect of this particular varnish, which was assumed to have a typical thickness of 0-.005". The result is a lowering of the peaks of wood resonance by about two decibels. Averaged over valleys as v/ell as peaks 9. the loss might approximate one decibel. That this loss is not to be ignored is apparent when it is compared with the five decibels which separate un outstandingly full-tone* instrument from one which is on the verge of mediocrity (Lottermoser)., Use of an inferior varnish could easily spell mischief. And even with this reputedly good varnish, what will be the effect of long drying? Obviously we need to investigate fillers also. The foregoing estimate assumes that a good filler isolates the varnish from the substrate. It may be tjjfltt the "secret of the old Italian varnish" is rather a secret of varnishing. In the Hill book on Stradivarius, a similar remark is made without venturing, to enlighten us further. Could it be that the secret is the technique of using the least possible amount of varnish? This might include as sub-secrets a virtuosity in preparing a wood surface with the ultimate in smoothness, a varnish having a consistency which is optimal for smooth application, and a brush or other tool which gives ohe maximum effectiveness per mil of thickness,.
16 17 summarizes the results of the Further details: The following table experiment. Decremen Tone. Fre queno; in c .00454 .00154 1 413 407/- 2 -5.8 -1.4 .00300 -15- -1.3 .0026 .00423 .00163 2 1155 1140 .00481 .00167 2270 2242 --28. -1.25 . 00314- 3 -47. -1.25 -.00268 .00413 .00145 4 3753 3706 .00288 .00434 .00146 5 5602 5531 -71. -1.27 Average: -1.3 .00286 .00155 k K-l* gives ordinal number of the "tone" The second The first column the considerably Though the strip (old window glass) givls frequency. to|*P^edtheoretical. fa^he5 \„a t+~%&e^the freauencies form a series close ld glaSs was IXO0 than my old strip. (The average Increments toQ,^^^the glass). ' much of the loss may have been extraneous ° column gives frequency after varnishing The third fifth gives percentent frequency change (always a drop , while theJ^.f^' *f fourth the error and is all SoH= tm» is constant within experimental mass o? ?h?varnish. This is shown by weighing before SfS! tfthf the mass of the and^af^ffremoval of the varnish average oi that of the varnish 0.33, a change of. 2. 4*..The grams and 1.3*, is almost exactly °nlllllm five representing a frequency decrease of this increase in mass. Since frequency depends onStent with 2.4* expect the change in inversely on the squar4 root of mass, one would change of mass, that is, 1.2* provided there freaufncy to he one-half the not cause The 1.2* and 1.3* are so close together that it is ff^ntLr significant elastic effect in the varnish that $olBSJ£w accuracy. would he detected with experiments of this on glass does not This absence of an elastic effect from varnish on wood. Comparing the modulus of mmiv a similar absence for varnish spruce glased efx 1010 with a typical cross-grain modulus in of the modulus for varnish could easily o q i lOlO'cgs, itis obvious that with respect to that of glass while being considerable S; nLli«iblf with measuring Glass is therefore unsuitable in res^ft to that of wood! spruce should be elaftioity of varnish. For this purpose cross-grain acceptable, in spite of hygroscopicity. g is at hand: 6 x 10 one measurement of Young's modulus for varnish coSl°«w"«^!»SS»" nS. "a. S«. i. " thousandfold di«=oo„aa
a rubber band gave i"e?vraS a rS measurement of the modulus of varnish measurement quoted). My dynamic measure- flTio67sale'o?der Is is times greater. ment of thfimSSSr? modulus of varnish, Hw, 400 6 7>and 8 ive The varnSfr Sh .1 sS Sh , « decrements as measured lld° ' toM t0 tone though the vi?es are r::gh^ ■* < by the process of X^Xt these*^r a,tlonßI" re eh reduced subtraction which *aye the Lit ; Zt £S " I- ""* ±n Perl^S^Sfe^^"ental err *'l «I\\VSX varnxshln°MS nfS L* findependentf r of "hf^creLnt of our interest. " frequency-within the range IU6S f HW ited StoVe formuLr ° ° Utem 5) obtained by the following Rw y ~ A - A6 3ir —E s He '/nere E s is modulus of substrate, y ta thick e ss of varnish (sum H S f 2 of both sides)8J s is thickness of substrate. ' The same fonwla was used in estimating the effect of varnish on spruce
Again it is the editor's pleasure many to TthanknaaK: .+h*tne members w^osewhnqp worthywn-n+w i~Ticontributions-v ' maaeniadP this+hi« fissue possible. have
Robert E. Fryxell
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