Catgut Acoustical Society, Inc

CATGUT ACOUSTICAL SOCIETY, INC.

J NEWSLETTER

Number 40, published semiannually November 1, 1983

Since our last Newsletter members of tbe CAS have participated in conferences and concerts all the way from lowa to Paris and Stockholm with Cincinnati in between. The conference in lowa was organized by William Savage - the Fourth conference and workshop on "Acoustics and the Physics of Sound and Music." This included not only invited papers by Gabriel Weinreich and Carleen Hutchins, but a concert demonstration and lecture on the VIOLIN OCTET which featured several pieces written for the top six instruments. The two big ones were not shipped out because they were being finished for something exciting in the Fall. Closely following the lowa conference was the 105th Acoustical Society of America meeting in Cincinnati. In addition to the technical sessions, the meeting included a buffet supper and CAS meeting hosted by Bob and Marge Fryxell in their lovely home in the suburbs? Mem- bers and guests were invited and all had a wonderful time with informal discussions as well as playing of music. In conjunction with their meeting, Carleen Hutchins spoke to the Cincinnati Community Orchestra following a buffet supper hosted by Ruth and Fran Rosevear. After the ASA meeting, CMH lectured to the Acoustical Consultants of America. Leo Beranek was in the group and contributed some interesting anecdotes of his early experiences as one of Professor Saunders graduate students during the time when Heifetz came to play his violins to compare the tone qualities of various instruments.

Later in May, Carolyn Field, who has been working with us in the shop for several years and playing some of the new instruments, particularly the Alto, was invited to give a talk at the Detroit meeting of the American Association for the Advancement of Science. Her paper - "The Hutchins Violin Octet: Past and Present" was well received. Since then the Australian Radio has done a broadcast on the VIOLIN OCTET and their musical potential including an inter- view with Carolyn.

The "Sound and the Fiddle" was the theme of a lecture-demonstration presented by CMH at the Bloomfield, N.J. library. She was assisted by Alan Scott, playing several selections on the Alto Violin as well as demonstrating the Tenor and Baritone. Also, Eileen Ivers played several of the small instruments (Mezzo, Soprano and Treble) as well as conventional violins. Much to the delight of the audience, Mrs. Ivers played some of the Irish dance music for which she is famous all over the world. It was a rewarding occasion.

Mary Lee Esty was invited by the Violin Society of America to lecture on the "History of Violin Acoustics" since CMH was unable to do it. This included a review of the early develop- ments which have been published in the paper referred to elsewhere on the History of Violin Research published in the Journal of the Acoustical Society. There have been many fine comments on the job which Mary Lee did. The Violin Society of America is holding their 11th Annual Convention at the Parker House, Tremont & School Streets, Boston, on November 11,12,13,1983.

At the end of May the complete VIOLIN OCTET was crated up at 112 Essex with the help of Tom Coleman and sent out to San Diego, California, in care of Bertram Turetzky of the Music Depart- ment of the University of Southern California in La Jolla. This is in anticipation of a concert demonstration of the OCTET which is being featured at the Acoustical Society of America meeting in San Diego. The concert will take place Wednesday, November 9th at 4:15 P.M. at the Town and Country Hotel, Town and Country Room, 500 Hotel Circle N., San Diego. Turetzky reports that the instruments arrived safely and they are excited to be working with them. Turetzky had worked earlier with Henry Brant, who is now in California and who will participate in this conference and concert where they will be playing some of his music.

The International Congress on Acoustics in Paris brought together members of the CAS from various countries around the world: Australia, China, India, Japan, USA, U.K. and many of the countries of Europe. There were many papers on the acoustics of stringed instruments as well as other instruments. Particularly interesting is the work that Dr. Heinrich Dunnwald is doing. He is a young violin maker and researcher who is combining the construction of instruments under varying conditions with the effects on their acoustics. His work should give us a good deal of further information in the next few years. A session at IRCAM (Institut de Recherche et Coordination Acoustique/Musique) , which is the Pierre Boulez center for musical research, was most interesting and the group had a chance to see the wonderful facilities con- structed underground near the new Georges-Porapidou centre in Paris. The meeting there was hosted by Pierre Boulez with discussions of the work they are doing by several of his staff

*Those present were: Eric Arnold, Joseph Bein, Arthur and Virginia Benade, Jacques Chamuel, R.O.Cook, Edith Corliss, William Doolittle, Robert and Marjorie Fryxell, Adrian Houtsma, Carleen Hutchins, Robert and Sue Latta, Raymond Lewkowicz and wife, lan Lindevald ,Max Mathews, Herman and Eileen Medwin, Dale Rogers, Thomas Rossing, William Savage, Arnold Tubis, Gabriel Weinreich, Earl Williams, Ellery Wilson plus several others.

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A of 112 Essex 07042 meeting the Officers and Trustees was held April 10,1983 at CAS headquarters. Present were: Carolyn Field, George Foy, President Daniel Haines, Carleen Hutchins, Morton Hutchins, Dugald McGilvray, Robert Scanlan Elizabeth McGilvray, Richard Menzel, Robert M. Meyer, Oliver Rodgers, 34 Burning Tree Lane Richard Robert N.J. 08648 and Beth Scanlan. Vice-President The following slate was submitted by the nominating committee, Morton Hutchins Ethel Piggins, and 112 Essex Avenue chairman, accepted. N.J. 07042 Trustees : Vice-President Maurice Hancock George Foy elect 2 year term White Salisbury Road Richard E. Menzel re-elect 2 year term Farnborough, Hants Daniel W. Haines England 2 year term Carolyn Field 2 year term Vice-President Robert E. Fryxell 3 term McLennan year John George Bissinger 3 year term 28 Highland Close " N.5.W.2290 Robert Meyer elect 3 term Australia Oliver Rodgers " 3 year term 3 Vice-President Richard Sacksteder year term Helmut Muller " Miiller-BBM GmbH Officers : Robert-Koch Str.ll 8033 Planegg b. Munchen Morton Hutchins Vice President, USA elect- 3 year term West Germany Maurice Hancock U.K. Vice-President John McLennan ii Australia !1 Johan Sundberg Helmut Muller ii Europe Royal Inst. Technology 10044, Stockholm 70

Treasurer Warren Creel 456 Hamilton Albany, N.Y. 12203 Rex Thompson, 10 Rothesay Avenue, Hazelwood Park, South Australia 5066, will accept dues from Australian Secretary members before March 1, 1984 only. Bills will be sent out in Hutchins January. 112 Essex Avenue Hannan, N.J. 07 042 Norman E. 18 Lake Rise, Essex RMI 4DY, England, will also accept dues payments from U.K.members. Details Financial Secretary in January dues mailing. Dugald McGilvray 12 Clalridge Court N.J. 07042 ************** Editor NECROLOGY Robert Fryxell 8430 Hickory Drive Robert Ohio 45243 Bishop,Newark, Nottinghamshire,England John W. San Diego, California * .11 general mail should be addressed t ffice address. Newsletter material to *************

members. CMH had some very interesting discussions with Voichita Bucur on further possibilities for testing wood for violins both as to the age of the wood and its micro structure as well as information that can be gotten from ultra sonic tests. This should prove fruitful and particularly interesting for those who wish more information on what happens to wood for violins and why it seems so critical under certain conditions.

After the busy and exciting ten days of the ICA in Paris, CAS members went on to the Stockholm SMAC (Stockholm Musical Acoustical Conference 1983) where Johan Sundberg, Erik Jansson and Anders Askenfelt had organized a very fruitful and rewarding conference. Details of this will be written up i. a later Newsletter, but suffice to say it was a rare opportunity for all of us to exchange ideas and to find many new conceptions and challenges as we talked to each other and listened to the papers that were given. A high spot of this conference was not only the CAS meeting discussion which we had one but also the very fine concert which was given under the auspices of the Royal Academy of Music at the Swedish Musik- museet. This concert was the culmination of the composer contest for the VIOLIN OCTET instruments and three winning compositions were played with two of the composers present. The musicians were assembled and trained by Semmy Lazaroff who did a beautiful job. The conductor was Miklo's Maros.

Before going to the ICA Hutchins visited with several violin makers in Italy. She was met at the Rome airport by Beate Kienitz, a young lady violin maker working in Rome, who drove her around Italy for visits which included several days with David Fix and his wife, Rene, in their lovely home in Cetona where David is working on an analysis of the Condax varnish papers. Then a visit to Cremona where Hutchins had a very cordial reception with Francesco Bisolotti as well as Bruce Carlson who is doing some very fine repair work on the old instruments in his shop in Cremona. The Cremona school was closed but Bisolotti served as guide to several places of interest related to the work of Stradivari and hosted a very lovely luncheon. He was much interested in the work of the CAS and we will keep in touch as time goes on. The visit in Cremona also included staying with two of the young men who are working at the violin making school - Renard Neumann from Canada and Francesco Moroni of Rome who produced some very fine Italian food. Most impressive of this visit in Cremona, in addi-

CAS

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tion to seeing the instruments of was the fine work that Bisolotti and his sons are doing in their shop - not only on violins, but violas, cellos and basses. It is a chal- lenge to the work of all of us.

CAS members who have stopped by 112 Essex include George Bissinger, working and research- ing; Oliver Rodgers, who is getting together blueprints for the Baritone and other instruments; Raphael Bernstein, Alan Carruth, Carolyn Field and Tom Knatt, who are working on instruments of the VIOLIN OCTET David Walter gave a Double Bass Recital at the Manhattan School of Music #" Congratulations to Frank Lewin, who has been made a full Professor at Yale University also to Robert W. Pyle, Jr. who received his 25 year award from the Acoustical Society of America to the Violin and Guitar Makers Association of Arizona on their Silver Anniversary which was celebrated at a convention in Tucson in October tr-irti The TV show 3-2-1 Contact, filmed at 112 Essex earlier this year, is scheduled for viewing on Public Network (Channel 13 in the Metropolitan area) November 24 at 5:30 P.M. ************** A special CAS meeting was held Sunday July 31, as part of the SMAC-CAS conference. Those attending: Anders Alexander Bell, Eric Boons, George Brock-Nannestad, Voichita Bucur, Michele Castellengo, Rend Sylvaine Ove lan Firth, Colin Gough, Maurice Hancock, Birgit Hansen, Carlo Hansen, Carleen Hutchins, Erik Jansson, Cary Karp, Max Mathews, Jesus Alonso Moral, James Parrott, Michael Rafferty, Bernard Richardson, Thomas Rossing, Charles Taylor, Dag Thunquist, Jon Tro. Due to scheduling problems five other members missed the session (Jurgen Meyer, Helmut Muller, Elizabeth and Dugald McGilvray and Johan Sundberg) All were very enthusiastic about the work of the CAS and its helping to coordinate research in musical acoustics around the world. CM. Hutchins gave a brief historical review of the founding and development of the CAS from the original four (R . E .Fryxell , C .M . Hutchins , F .A. Saunders and J.C. Schelleng) - to the official founding in 1963 with 20 members to the present 800 + in 27 countries today. James Parrott reported on the status of his Citation Index and indicated coopera- tion with the CAS information center at Stevens Institute of Technology, particularly in devel- oping a set of key words for use in information retrieval. The subject of our Newsletter title was discussed. Librarians usually cannot offer subscrip- tions to Newsletters, but can to JOURNALS. The group voted unanimously to recommend a change in masthead to "JOURNAL OF CATGUT ACOUSTICAL SOCIETY" - also each year (2 volumes) page numbered 1 2 and a table of contents.

The meeting was followed by a continuation of the poster session so all could hear and dis cuss the various instruments involved. *********** NEWS FROM CLEVELAND: Things have been very busy and productive here in Cleveland in the past few months, with my own recovery from surgery a year ago being neat and uneventful. Karl Washburn this spring completed a very beautiful senior project "The One-microphone Method of Determining Acoustic Intensity Vector Fields" based on the work of 0. Kr. 0. Pettersen of Trondheim, Norway. Karl, who has gone on for graduate study in acoustics at Perm State, and I had planned to write a little essay on this work for the CAS readership to call everyone's attention to a powerful and elegant technique that calls for a minimum of equipment. Now it turns out that Pettersen himself is providing the introduction. Anyone who wishes to see Washburn's 31 page report is welcome to write me for a copy. Peter Hoekje and I (with strong help from George Jameson of Milwaukee) have managed to get firm hold of the way a wind instrument player's own windway resonances couple with those of his horn to enhance or to disrupt the musical regimes of oscillation. The musical and acoustical implications are large, and already fruitful. A5O page report on this will appear in the Proceedings of the lowa City Conference on Physiology and Biophysics of Voice (May 1983). It will probably also appear in the Proceedings of the musical acoustics conference held this September in Kraslice, Czechoslovakia. Peter and I are working hard on a more detailed account to appear in JASA. Lan Lindevald and I are getting well into the psychoacoustics business of musical hearing in rooms. I will be presenting some of our thinking along these lines at the October meeting of the Audio Engineering Society. The manuscript for this paper has been sent for publication in the Journal of the AES. My newly designed NX clarinet and its cousin, a "baroque flavored" Boehm flute from some years ago continue to attract favorable attention, and some are in process for eventual sale. Among the many visitors I will mention only two: Yoshinori Ando of the Kyushu Institute of Design and Carl Hanson. The latter is a flute and recorder maker from England who is here for several weeks. We hope to produce an orderly account of diagnosis and adjustment procedures for these instruments in the service of the serious craftsman. It is worth mentioning that George Jameson and I are (more slowly) working on something analogous for today's woodwinds. Last but not least I want to mention that some of my little experiments on the modification of a violin for improved articulation, less scratch, and fuller tone were given a very interesting checkup by Joe Bein during the ASA Meeting in Cincinnati in May. The chance to get Carleen Hutchins 1 reactions, and her (enormously successful) recutting of my somewhat unconventional bridge, plus to talk about many things concerning this fiddle with Earl Williams were also very valuable to me. Violin physics has always had a way of "sucking me in", so that my head was buzzing with new possibilities during the home- ward trip. This is dangerous ... too many things are going on here already.' Arthur Benade

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The Newsletter has, over the years , acquired ity of the Newsletter and setting criteria a very respectable technical stature. This for acceptability of future articles. Chief fact has, in the opinion of the undersigned, among these criteria should not necessarily merited a certain reappraisal of the general be scientific complexity or sophistication quality of future articles accepted for the per se, but rather simply the furtherance of Newsletter . the quality of stringed instruments through insights that bear directly on the problems Highly respectable technical journals have, at hand. This may well narrow the scope of as a matter of general practice, established the Newsletter but can, if properly directed, editorial boards that screen submitted arti- lead to an increase in its value to the string cles. This has become indispensable to the community . continuing quality of those journals. Period- Sincerely ically, the call goes out to increase the dis- , crimination and vigilance exercised over the Robert admission of articles for publication. H. Scanlan Professor of Civil Eng University I would like to suggest here that the Catgut Princeton Newsletter further emphasize action in an analogous direction. A number of past articles appearing Newsletter have borne only rath- in the The above comments by Professor Scanlan are indeed er remote connections to the improved under- thought provoking. One cannot disagree with any change or ame- standing of stringed instruments to the such as a tighter reviewing policy which will enhance lioration of the thereof. have quality the stature of our Newsletter. merely recounted information only tenuously re- already well-respected The question of scope is another matter. Is our lated to the real of instru- problems stringed charter solely "furtherance of the quality of stringed ments. It would now be highly desirable if a instruments"? (as he states it). Taken literally, decision were made in favor of a sharpened ed- this includes itorial focus to be exercised in the future, considerably restricting articles of too lit- -acoustics research, materials research tle or too remote pertinence. but less obvious would be the relevance of such Even a very conscientious author may oc- subjects as casionally be overly persuaded of the cogency -room acoustics, psychoacoustics and applicability of his own article. A third -improved tools and techniques for makers party or editorial board may view it different- -history of strings, instruments and bows. ly. Authors are frequently on private voyages of discovery which, though fruitful, may not The question becomes one of definition. Which of the automatically produce results that are publish- above subject areas are supportive of our charter as able under more rigorous criteria. Prof. Scanlan states it, either in a reasonably direct way or by osmosis? Or is this charter too I would therefore like to see the articles restrictive and should it include broader aspects in the Newsletter pass through a more severe of total musical experience? Readers are urped editorial filter. I believe that the Catgut to offer comments as the Newsletter enters its Society ought now to give serious considera- third decade. tion to the establishment of a set of guide- EDITOR lines aimed at further tightening up the qual- ************ ************ Thanks to the Luthiers! and night stand, all made of cherry wood in a modern Shaker style. As a result of growing up with violins, and seeing their beautiful designs, workmanship In the near future I will retire and if all and finishing, I have developed a serious hob- goes according to plan will have an occupation by--cabinetmaking. There is no question that that is both enjoyable and productive. the subconscious appreciation of fine wood, its potential for attractive grain patterns and In all this activity I still stand in awe of color, developed in me because of daily expo- the fine joinery of the great Luthiers. Their sure to string instruments. I still teach mu- use of the aesthetic principles of similarity sic at a midwestern university, but most of my and contrast in the juxtaposition of wood in a free time is spent at a well-equipped cabinet string instrument is a constant source of in- shop, located on a farm a short distance from spiration. One of the lessons we learn from my apartment. them is the concept of the instrument as a composition, an artistic whole, despite the variety The woods I have worked with have been of elements which are involved. This principle largely hardwoods: oak, cherry, walnut, ma- can and should be applied in designing and mak- hogany, birch, maple and beech. There have ing furniture. The violin also gives us the been softwoods, too: pine, poplar, redwood and ideal of combining the aesthetic with the func- cedar. tional . It has been a broadening experience to work The arching of the instrument typifies this with people in a non-academic and non-musical principle, as do the shape and function of the setting. The variety of products we have made sound-holes. The varnish is both a protective seems endless and some of them were unusual preservative and a great source of beauty. and challenging. A piano mover ordered two "dollies" (skids), one for moving uprights and Had I begun woodcrafting at a younger age I one for grand pianos. A man stricken with mul- would probably have taken up violin-making. In tiple sclerosis ordered a platform and ramp to the meantime I salute the Luthiers with their get his wheel-chair out of the house and down great craft and artistry. They will alwayshave to the driveway. A voice teacher ordered a my respect and gratitude. large four-poster bed (with canopy), a dresser Joseph Bein

CAS EDITOR

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clear, but it is limited by being removed from a broader AUDITION PREFERENCES OF TRAINED AND UNTRAINED musical context. However, the intervals presented EARS ON HEARING MELODIC AND HARMONIC INTERVALS were in their two basic patterns, successive and simultaneous, WHEN TUNED IN JUST INTONATION OR PYTHAGOREAN are materials. RATIOS. and two patterns basic musical (Tapes for Supplements 1 and 2 available for consulta- The complete data are presented in five tables. Table tion at the University of Texas at Austin Library) . I is analyzed in detail because it concerns the "tonally simple" intervals: thirds, sixths, augmented and Howell Pierre Branning whole tone. The hypothesis tends to be substantiated by The University of Texas the data of Table I. This study is concerned both with the problems of in- The conclusions of the study are as follows: (1) The tervallic hearing and with audition preferences. The hy- pretest tape showed that the simple phenomenon of 'beats" is that Man hears musical intervals in their pothesis me- was recognized by a surprisingly small of lodic or harmonic and desires two different tun- percentage contexts prospective subjects. This acoustical phenomenon and ing systems according to these varying contexts. its relevance to music theory should be presented to students at an early age. This be done in the class- The first purpose of this study was to discuss the in- can herent problems involved in intervallic tuning. Four ba- room, as another study has shown. (2) A preference for sic problems have been defined: (1) discrimination (dis- just intonation was shown in harmonic intervals where the tinguishing differences by discernment); (2) tolerance intervals were the less complicated ones. (3) Melodic in- are more (the acceptance of deviations from a given standard) (3) tervals difficult to distinguish than harmonic presentation "detuning" (the demand of the ear for deviations from true intervals. (4) In the of two intervals of theoretical values); (4) tuning preferences (choosing or different types, one melodic and one harmonic, the me- esteeming one thing above another) These issues have lodic interval will always be preferred if the harmonic . (5) been confused in much of the literature, and it one interval produces beats causing a harsh dissonance. was "tonally goal of this study to make these problems clear. The The complicated" intervals are even more difficult the tuning differences second purpose of this investigation was to open the way to understand; are were for further research in intervallic preferences and to still harder to distinguish. (6) The subjects present data of tuning preferences as given by subjects exposed to those intervals in their two different musical first would un- of six groups selected from 1,100 persons tested by a pre- contexts for the time. Training results, as a test tape. These data have been analyzed in some detail doubtedly influence the related study has shown. Because of the above conclusions and the fact in regard to some of the intervals: the major third and sixth, the minor third and sixth, the augmented that flexible tuning occurs in the performance of music fixed and the major whole tone. in all media except keyboard instruments with pitch, intervallic training in these two basic, dis- The form of the questions asked the subjects was lim- tinct systems should become part of the music curriculum. ited, so that a simple preference answer could be re- Reprinted from DISSERTATION ABSTRACTS, V01.XXV111, quired. This limitation made it necessary that the questions be removed from a broad musical context and placed A microfilm or xerographic copy of the complete manuscript on form. tape in simple Each question consisted of two is available from the publisher,University Microfilms ,Inc. required a preference intervals and choice. This manner Ann Arbor, Michigan. Microfilm $3.00; Xerography of presentation has the advantage of being simple and 112 pages.

Polish musicians are very interested in the POLISH VIOLIN MAKERS ARTISTS ASSOCIATION OF creation of Polish violin makers. Musicians of chamber orchestras play polish modern in- The tradition of Polish violin making goes many struments (Wilanow Quartet, Polish Chamber Or- back to XVI century when the Cracov School for chestra under the conductor J .Maksymiuk) violin making, represented by such violin mak- . ers as M. Groblicz, M. Dobrucki, B. Dankwart The members of the Association (ZPAL) make was founded. In 1954 the Association of Polish all types of modern and historical stringed in- Violin Makers Artists was created and in a short struments (Viols, lutes and the like). Polish time it assembled the most gifted violin makers; modern instruments have been bought by Sweden, the Association has undertaken the crisp activ- Norway, Yugoslavia, West Germany, USA, ities for intensive development of present art Netherlands, France, Mexico, Belgium and Italy. of violin making. ARS POLANA ENTERPRISE Since 1957 in Poland the H. Wieniawski Inter- FOREIGN TRADE national Competitions for violin makers have been Krakowskie Przedmiescie 7 organized - the greatest performance in the world 00-068 Warszawa, Poland devoted to violins only. ¥¥¥¥¥¥¥¥¥¥¥¥¥ Dr. John W. a long time member of the Catgut are two secondary schools in Poland for There Acoustical Society died April 30, 1983. A native of violin (Poznan, Zakopane) and the best making Montclair, New Jersey, he obtained his A.B. degree from graduates from these schools have studied at the Rutgers University, studied at the University of Chicago Academy of Music in Poznan. before entering Rush Medical College where he earned his post Mayo The position which the Polish violin makers M.D. degree. His graduate years were spent at Clinic , Minnesota in radiology. joined occupy is due to artistic triumphs of individual Rochester, He the medical department of the creators as the proof there are numerous U.S.Navy during World War - II and served the South Pacific. After the war prizes (first also) and gold and silver medals in he returned to San Diego where he was associated with the that have been awarded at the International Com- Medical head of and Exhibitions: Exhibition of Viola Radiology Group; radiology department petitions of Mercy Hospital; member of American and California in Ascoli Piceno, The Elizabeth Competi- Medical Association; San Medical and a tion for String in Liege, The H. Diego Society Quartet Diplomate of the American Board of Wieniawski Internationale Competition for violin Radiology. His hobby makers. Polish violin makers have been invited of violin making developed upon retirment and he was an active member of very often to Japan to take part in Exhibitions. the Southern California Associa- tion Violin Makers. To all those who knew him there is a deep sense of loss.

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Queen RECENT PUBLICATIONS 6 NL Nov.

Jont B. Allen "Magnitude and phase-frequency response to single tones in the auditory nerve," JASA Vol. 73 (6), June 1983, pp. 2071-2092. A.H. Benade, W.Bruce Richards, "Oboe normal mode adjustment via reed and staple proportioning," JASA V01.73 (5), May 1983, pp. 1794-1803. Alan "Hammer Dulcimer," Guild of American Luthiers, Data sheet 233. Ove "The response of played guitars at middle frequencies," J.Guitar Ac,May 1983,pp. 49-60. R.E.Davis, A. Tubis, "Vibrations of Timpani Membrance 11. Theory and observations of air loading and T.D. Rossing, effect of varying kettle volume," PACS numbers 43,75 Hi, 43.40 At. Edith L.R.Corliss, W.B.Penzes, "Low noise broadbend modulated preamplifiers for a variety of transducers," Applied Acoustics, Vol. 16, N.l, Jan. 1983, pp. 67-74. Diana Deutsch, Reply to "comments on 'ear dominance and sequential interactions' by E.W.Yund. JASA Vol. 73 (5), May 1983, pp. 1865-1867. " Carleen M. Hutchins, "A History of Violin Research," JASA Vol: 73 (5), May 1983, pp. 1421-1440. Carleen M. Hutchins, "Violin Acoustics," by I. Nakamura and Y. Nagai. J.Acoust. Soc.Japan, Vol. 39 (3), 1983. (Japanese) pp. 204-213. Carleen M. Hutchins "Musical Instruments," (pp. 300-303). McGraw-Hill Yearbook of Science & Technology, 1984. (Updating supplement to the McGraw-Hill Encyclopedia of Science & Technology, Fifth edition. McGraw-Hill Book C0.,1221 Avenue of the Americas,New York N.Y 10020 ISBN 0-07-045492-2 S, Koshigoe, Arnold Tubis, "Frequency-domain investigations of cochlear stability in the presence of active elements," JASA Vol. 73 (4), April 1983, pp. 1244-1248. S. Koshigoe, Wai-Kwong Kwok, "Effects of perilymph viscosity on low-frequency Intrachochlear pressures and the Arnold Tubis, cochlear input impedance of the cat," JASA Vol. 74' (2), August 1983, pp. 486-492. Bo Lawergren, "Harmonics of S motion on bowed strings," JASA Vol. 73 (6), June 1983, pp. 2174-2179. A.R.Lee, M.P.Rafferty, "Longitudinal vibrations in violin strings," JASA Vol. 73 (4), April 1983,pp. 1361-1365. Roger Mather, "The Art of Playing the Flute," a series of workbooks-Vol. l,Breath Control,Vol.ll, Embouchure. Romney Press, Box 2570, lowa City, lowa 52244. "Influence of Tube Material and Thickness on Flute Tone Quality," Woodwind World, September 1974. "Flute Tube Material and Thickness," Woodwind World, April 1974. "Is your Flute Vibrating Properly," Woodwind - Holiday 1974. "The Flute Sound of George Laurent ."Woodwind World-Brass & Percussion, March-May 1976. Joanne L. Miller, Thomas Baer, "Some effects of speaking rate on the production of /b/ and JASA, Vol. 73 (5), May 1983, pp. 1751-1755. J.L.Miller,CM.Connine, T.M. "A possible auditory basis for internal structure of phonetic categories," Shermer, K.R.Kluender, JASA, Vol. 73 (6), June 1983, pp. 2124-2133. Norman Pickering, "Anomalies in the frequency-length functions in violin strings," J.Audio Eng. Soc, Vol. 31, N0. 3, March 1983, pp. 145-150. H.F. Pollard, E.V. Jansson, "A tristimulus method for the specification of musical timbre," Acustica, V01.51,N0. 3 J.982. "Analysis and assessment of musical starting transients," Acustica, V01.51, N0. 5* 1982. Royal Swedish Academy of Music, "Function, construction and quality of the guitar." Papers given at a seminar organized by the Committee for the Acoustics of Music,, Ed. Eric Jansson. "Acoustics for the Guitar Player," Eric Jansson "Acoustics for the Guitar Maker," Eric Jansson "The Function of the guitar body and its dependence upon constructional details Jurgen Meyer ' " H.J. Sathoff, Thomas D. Rossing, "Scaling of Handbells," JASA, Vol. 73 (6), June 1983, pp. 2225-2226. Theodore Steinway, "If Rivers Talk," J.Guitar Acoustics, Vol. 2, No. 3, May 1983. Tarnoczy, T. Is it possible to measure annoyances by sound-pressure measurement," Kep es Hang Technika 1982, Dec. XXVIII. EVF. 161-192 old. N.H.Fletcher, "Acoustic admittance of organ pipe jets," JASA, Vol. 74 (2) August 1983,pp. 400-408. T.White, Mary-Margaret Wallsworth, "God's Luthiery," J.Guitar Acoustics, Vol. 2, No. 3, May 1983.. Earl G. Williams, expansion "A series expansion of the acoustic power radiatedraMai-^A fromfr planar"i sources," JASA Vol. 73 (5), May 1983, pp. 1520-1524. "Numerical evaluation of the radiation from finite plates using the FFT " JASA, Vol. 74 (1), July 1983, pp. 343-347. The Journal of the Acoustical Society of America, Supplement 2, Vol. 73, August 1983, contains a reference to con- temporary papers on acoustics. Papers listed by CAS members: Editorials-Surveys and Tutorial paper5 ...43 .10: H.F.Pollard; Architectural acoustics ...43 .55 Y. Ando; Psychological acoustics. . .43.66 E. Jansson, H.F.Pollard, T. Tarnoczy; Speech Communication. . .43.7o: A E.V.Jansson, J.E.Miller, J.Sundberg, T. Tarnoczy, E.Terdhardt; Music and Musical Instruments.. 43.75: M.J.Alonso, N.Fletcher, E.V.Jansson, B.Lawergren, M.E.Mclntyre, J.Meyer, I.Nakamura, H.F.Pollard, T.D. Rossing, T.Tarnoczy, J. Woodhouse; Acoustical measurements and instrumentation.. .43.Bs: T.D.Rossing. Sangeet Research Academy (A trust created by ITC Ltd.) publishes a Journal dealing with Indian classical music and musical instruments, as well as other research in acoustics. Those Interested may contact Smt. Dipali Nag, 1 Netaji Subhas Ch. Bose Road, Calcutta 700-040.

CAS #40, 19?

Carruth, Christensen, R.S.Christian, C.A.Anderson,

Trans,

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S.Thwaites,

of nnwr nm ,=*.

unbaffled,

Askenfelt,

R.T.Schumacher, NL #40, Nov. 1983 7

For our Scandinavian readers, we list below several publications of interest which may be ordered from Ake Ekwall, Hantv. g. 9, 77700 Smedjebacken, Sweden. (Prices are in Swedish crowns). GEOMETRI I FIOLEN ay Ake Ekwall Popular delredovisning ay forfattarens stora undersokning betr de gamla mastarfiolernas formgivning. Duplikat ay artikelserie i SLOJD OCH TON 1970 - 1975. - Pris kr 110: - PLATTAVSTAMNING FOR FIOLBYGGARE ay Carleen Hutchins. Knacktoner, vrid - och bojprov, nodmonster, partikelmetoden - allt beskrivs sakligt och lattforstaeligt sa att lasaren sjalv kan tillampa de nya kunskaperna. Rikt illustrerad. - Pris kr 65: - PARTIKELMETODEN ay Ake Ekwall och Erik Jansson. Sammandrag ay tidigare U.S.A. litteratur om Carleen Hutchins plattavstamningsmetod fram till ar 1976. Bl a beskrivs i detalj avstamning- ay basbjalke. Duplikat ay artikelserie i SLOJD OCH TON 1977-78. Pris kr 65: - SYSTEM VIOLIN NR 15 ay Ake Ekwall. Detalj erad fiolritning mcd tre valvningsvarianter for lock och tre for botten. Forfattaren har forsokt ge en mattsatt formbeskrivning for den fiolmodell Carleen Hutchins hanvisar till i ovanstaende tva verk, d v s Sacconi bokens Stradivari fran 1715. Mcd salunda definierade och matbara former bor fiolbyggaren kunna undvika en del onodiga, slumpartade foreteelser, som eljest latt kan stora kontinuiteten i en metodisk inlarnine ay fiolbygge. - Pris kr 95: - SYSTEM VIOLIN NR 16 ay Ake Ekwall. Detali erad fiolritning. Samma fiolmodell som foregaende Nr 15. men mcd valvning inspirerad ay Josef Kantuschers valvningsprincip. Endast en valvningsvariant for lock och en for botten. - Pris kr 65: - PARTIKLAR for avstamning enligt partikelmetoden. Ay svartfargad aluminium, 0.9 x 0.9 x 0.1 mm. - Pris pr 10 kr 20 ANTECKNINGSBLAD VID Ake Ekwallsmodell. Far garna kopieras och spridas. - Pris pr 50 st kr 30: FORSALJNINGSVILLKOR: Vid leverans medsandes rakning och inbetalningskort for betalning mom 2 veckor. Pa sa satt far Dv se varan innan betalning sker och sa sparar Dv in postforskottsavgiften. Moms ingar i angivna priser men porto tillkommer.

CORRECTION In "The Dynamics of Isolated Musical Strings" which appeared in Newsletter #38, author Maurice Hancock has pointed out an error in Figure 6: The numbers on the horizontal scale for the sth harmonic curves should be 1325, 1326, 1327 instead of 2209, 2210, 2211 as shown.

Sound radiation from a double bass visualized by intensity vectors J. Tro, 0.Kr.0. Pettersen, U.K. Kristiansen ELAB, N-7034 Trondheim - NTH, Norway The purpose of this letter is to show how Two successive measurements are taken at maps of intensity vectors can give a good phy- points 1 and 2, respectively related to -a sical insight to the energy flow in acoustic stationary reference signal. -For a single fre- fields. Combined with subjective measurements quency the phase difference determines the in- this may form a useful tool for the evaluation tensity direction while the complex pressure of the sound radiation from musical instru- moduli in the two points contribute only to ments. For studio production visualized sound the intensity magnitude . radiation from the instrument might be useful to avoid bad microphone positions in nearfield The measuring positions in the actual acous- sound recordings. tic field are described by equally spaced points in a two-dimensional lattice. The com- Experimental Methods plex pressure data at each lattice point is fed into a computer and stored. Grouping this data For stationary sound field, a single micro- in gives two intensity components in phone, together with a signal reference, might each direction. Averaging the components in be used to sample an area for complex acoustic the same direction and vectorially summing, pressure values. This "one-microphone the total two-dimensional intensity vector is 1 2 method" is described in and . The instrumentation referred to the midpoint in each lat- involves use of ordinary acoustical measuring tice cell . equipment only. (See fig. 1). The measured intensity results are presented as arrows from the midpoint of the lattice cells . The arrow length represents the intensity magnitude in decibels and the direction of the arrows describes the direction of acoustical power flow.

Calculations based on the same principle as described above are presented by Kristiansen 2 . Results

Musical instruments are interesting and com- Fig. 1: The one-microphone Intensity measuring plicated sound sources. Several reports de- equipment (from *) . scribe sound production and sound radiation from musical instruments , among others 3 and *

CAS

gram PLATTAVSTAMNING,

fours,

found, 8 NL Nov. 1983

The present Illustrations show examples of the steady state power flow around a double bass, measured in three different two-dimensional planes. (See Fig. 2)

Fig 2: Measuring planes: 88, SP, B BB: Vertical plane on the bass bar side

SP: Vertical plane on the sound post side

B: Horizontal plane through the bridge.

Fig. 3: Power flow in the B plane at 98 Hz. The instrument was excited steadily at 98Hz Solid lines show i so phase contours. and 230Hz by a B & X Minishaker connected to the middle of the G-string. The two-dimensional arrow maps (intensity vectors) give informa- v v-.\v\\s\\\\ti;i/////// tion about the local sources of radiation, the \\\\v\ \ \ \\\ of radiation and the direction of the magnitude \V\\V\\\\\\\ f power flow. At low frequency excitation the NNN\VN\\\\ \ I bass acts like a monopole, shown In fig. 3. As \ I t t- / S -» . NNV\\N\\\\ 1 A **>*. . seen, the f-hole originates the longest arrows, t t■ f ' . V S N S \ S \ \ \ f / S f — i.e. at this the f-hole is the main frequency VVVVNN\\\\ t / A . — . source of radiation. ! y . . VVV-^VVVNN \ f —^^ '—-^-^-^ -^ ~^ - At higher frequency several phenomena occur, like the power rotation in fig. 4. Such a S | S>» steady circulation of acoustic energy in closed ------'^jJIJXJ^-' 5 loops has been shown in reference The fig- "s — . ~T I S \ .K. "\ ure also shows a typical non-symmetric radia- :''' 'U : :\ \ / a --- tion in the near field area at higher frequen- , l\ A \t I . . _ cies. At this frequency (230 Hz) a region of *■ the back plate is an important source. This ** " V** v ->.\-»-~-- -"■ " --*■---■«-- -/ S —— — back plate radiation seems to contribute also < *■ s / / ; | >*-n.--» to the side way and frontal power flow in the *" * bass bar half plane. Fig. 4: Power flow in the B plane at 230 Hz. Acknowledgement

Part of this study was supported by the Norwegian Research Council for Science and the Humanities.

References 3. Tro, J., "Onset transients in music." ELAB report STF44 F78027, 1978, Trondheim. (Norwegian). 1. 0.Kr.0., "Sound intensity measurements for describing acoustic power flow." 4. Tro, J., "The influence of the surroundings on Applied Acoustics 14, 1981, 387-397. double bass sound recordings." Thesis, Norwegian Institute of Technology, Trondheim, 1973. (Norwegian). 2. Kristiansen, U.R., "A numerical study of the a- coustic intensity distribution close to a vibrat- 5. Smith Jr., P.W. et al: "Intensity measurement in ing membrane." Journ. Sound and Vib. ,1981,76(2) near fields and reverberant spaces. BBN Inc. 305-309. Report No. 1135. 1964.

CAS #40,

\ \ ft tftffsff S\\\V\\\\\\V\ tl/f/fSSS/ !t///SSSS^ \ t/SSS^^^S-** VNN\V\\\\\

S \ \ *» \ \ \ / /

/ \

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-v.S^^^- \N\

Pettersen, NL #40, Nov. 1983

Fig. sa,b: Power flow in the SP plane, 230 Hz.

Fig. 5 and 6 show radiation in the two vertical planes. It is seen that parts of the surface of the instrument radiate while other parts receive a- Fig. 6 a,b: Power flow in the BB plane, 230 coustic energy. Hz.

CUTTING GAUGE THREADED Louis R.Supek 1/4x20 2809 Alda Parkway Brunswick Ohio 44212 Cutting lining strips from a 1/8 inch sheet of bulk wood with a band saw or table saw can waste a lot of wood. If the saw blade is 1/32 of an inch wide or more only 32 passes are needed to convert one inch of wood into sawdust. The wasted wood could be made into a few more lining strips. The cutting gauge is easy to construct and is inex- pensive. It is made from material found in your workshop and consists of five items as follows: 1-hardwood block, 3/4 inch thick, 2-3/4 inches square 1_ 5/8 inch dowel rod, 7 inches long 1-^sx2o brass bolt XH. inches long. A threaded brass rod can be used. (super markets, hardware stores, etc have plumber's float rods which are ideal) 1-brass or aluminum strip, 1/16 inch thick, 1/4 inch wide, 1-1/4 Inch long 1-steel strip, 1/16 inch thick, 5/16 inch wide, 1-1/4 Inch long, for cutting blade

1) Drill a 5/8 inch hole through the center of the block. Insert the 5/8 inch dowel rod, sand smooth for a nice sliding fit. 2) With a N0. 7 drill, make a hole through the middle of the top of the block at right angles to the grain. 5) About inch from one end of the dowel rod, and Drill through to the top section of the 5/8 inch hole, 1/2 at right angles to the grain, drill a inch hole thread this hole with a *sx2o tap. 1/8 all the way through. 3) File or cut out a keyway across the top of the strip dowel rod hole, about 1/16 inch deep for insertion of 6) The cutting blade is formed from the steel 1 the brass or aluminum strip. Bend the strip into a grinding down both sides evenly about 3/4 inch from you of an a square "U" shape. The inner dimension should be the the top. The shape will remind arrow tip. width of the block, 3/4 inch. The tang is slightly over 1/8 inch so a tight fit cai be had when inserted into the 1/8 inch hole. The 4) The 1-1/4 inch brass rod is slotted at the top for lower end of the blade can be shaped pointed or a screwdriver fit. Thread the bolt or rod into the rounded. Grind and hone to a keen edge. threaded hole. The brass or aluminum strip prevents the bolt or rod from digging into the dowel rod when 7) Mix epoxy glue and cement blade into the 1/8 mcl making gauge adjustments. hole.

CAS 9

HOLE

CUTTING EDGE 10 CAS NL #40, Nov. 1983

THE MUSIC MUSEUM PERFORMERS : Sibyllegatan 2, Stockholm Friday, July 29, 1983 at 20:00 Thomas Lundblad Treble Violin Jan Isaksson Soprano Violin CONCERT WITH THE NEW VIOLIN OCTET Semmy Lazaroff Mezzo Violin Christina Wirdegren Alto Violin arranged in connection with the Stockholm Music Elisabeth Hahn Tenor Violin Acoustics July 28-August 1, 1983, Staffan Bergstrom Baritone Violin including the first performance of the winning Ingalill Hillerud Small Bass Violin pieces in the SMAC 83 Composition Contest for Eskil Henriksson Contrabass Violin the NEW VIOLIN OCTET INSTRUCTOR and CONDUCTOR: Miklos Maros PROGRAM JURY FOR THE COMPOSITION CONTEST Henry Purcell (1659-1695) Sven-Erik Back composer Final Scene from "Dido and Aeneas" (arr.L.Rackley) Sven-David Sandstrom composer Per Norgard composer Vladimir Kovar (1947- ) This concert and the composition The Canto and the Epilogue from the Triptyk for the contest was supportedby New Violin Octet (1982) The Royal Swedish Academy of Music (Prize-winner, first performance) The Irma and Albert Henneberg Foundation The Catgut Acoustical Society, Inc. Presentation of the New Violin Octet by the maker of the instruments - Carleen M. Hutchins T. Hauta-aho Octoballade (1982) (Prize-winner, first performance)

Lars-Ove Borjesson (1953 - ) Figuroj op. 35 (1982) (Treble, Mezzo, Tenor and Small Bass) (Prize-winner, first performance)

Erik Satie (1866-1925) Gymnopedia nr 2 (arr. L. Rackley)

Carleen Hutchins and Vladimir Kovar

Conference,

Contrabass NL #40, Nov. 1983 11

Exhibition Violinmaking A. Method credit (Associazione Cremonese Liutai Artigiani Professionisti) Ezio i, (A.C.L.A.P. Genova 1982) Italia Bicentennary of birth of Niccolo Paganini,Oct. 1982

Bjßrn Hagerman, Johan Sundberg, James Parrott, Michael Rafferty, Bernard Richardson Anders Lennart Nord Voichita Bucur (seated) (SMAC Banquet aboard the Gustavsberg VII)

CAS

Quires Cremona,

Askenfelt, 12 NL #40, Nov. 1983

Mrs. Muller,Helmut Muller,CM.Hutchins,Voichita Bucur, Erik Jansson and Max Mathews SMAC 1983

Blate Kienitz, CM.Hutchins,David Fix Cetona, 1983

Tom Rossing, Carleen Hutchins, Rene Causee, Gabriel Weinreich ICA, Paris, 1983

Erik Jansson, Jesus Alonzo Moral, Michelle Castellengo, Sylvanie Chaintreuil Maurice Hancock, Elizabeth and Dugald McGilvray

CAS NL #40, Nov. 1983 13

THE OF STRUTTING THE TOP-PLATE MODES A GUITAR

Bernard E. Richardson Department of Physics, University College, Cardiff U.K

1 Introduction along the grain and then across the grain. The struts were planed down in 1 mm steps from 5 mm to nothing, and at each This paper describes some experiments which stage I measured the frequencies, Q-values and shapes of a demonstrate the influence of struts on the mode frequencies series of free-plate modes. of guitar top plates. The strutting systems of classical guitars essentially consist of two types of struts, with one Modes were identified by means of Chladni patterns. set glued along the grain and the other across the grain of Rather than use the usual loudspeaker arrangement to excite the top plate. Many guitar makers believe that the tone the plate, I attached small electro-magnetic drivers to the quality of a guitar is critically affected by the type of plate and stimulated it directly. The mass of each driver strutting system employed. The greatest variation in design was very small (< 0.5 g). Using this form of excitation, it is in the arrangement of the fan struts; these are small is easier to isolate single modes, because the point of struts, most which are glued along the grain. excitation can be carefully controlled. When necessary, two the results presented here indicate that it is the height or more drivers, either in or out of phase with each other, and placement of the cross-grain struts which have the can be used to de-couple closely-spaced combining modes (for greatest influence on the mode frequencies of the plate, and an explanation of these techniques see Stetson and Taylor that the bridge might be the most important 'strut' of all. 1971). The plate was supported at nodes on triangular foam blocks so that it was essentially freely supported. Once a mode had been isolated, a microphone was placed near an 2 Free-Free Modes of a Square Strutted Plate antinodal region of the plate. The frequency of excitation was then varied about the resonant frequency of the mode so Before dealing with a complex shape such as the that the resonant frequency and -3 dB points could be guitar top plate, let us examine the modes of a plate of accurately determined from the detected sound pressure more simple geometry. The modes of rectangular plates are level. The were then calculated from the formula well documented (e.g. Waller 1961). They form a logical where f is the resonant frequency and df is the hierarchy of modes with nodal lines 'which are nearly always frequency separation of the -3 dB points. parallel to the sides of the plate. I therefore thought that it would be useful to study the modes of a square Figure 1 shows the results from the two experiments. spruce plate on which struts had been glued along and across The modes of the unstrutted plate formed a similar series to the grain to see what effect struts have on the mode the modes of a rectangular isotropic plate of a frequencies. length-to-width ratio of about two to one. The mode shapes varied very little when the struts were added. I did not A 250 mm square plate, 2.6 mm thick, was cut from a try to identify all the modes in the frequency shown, high-quality, quarter-sawn spruce board of the type sold for but rather concentrated on the lower-order bending modes. guitar making. Two sets of three struts were made from a single piece of quarter-sawn spruce. Initially, the struts As expected, adding struts had the greatest effect on were made smm high by 3mm wide. They were glued to the the frequencies of the simple 'beam' i.e. the (0,2), plate at quarter, half and three-quarter intervals, first (0,3), (2,0) and (3fo) but only when the struts were

Figure 1. Experimentally-observedmode frequencies of a strutted plate plotted against strut height. The plate was freely supported. Modes have been categorised as (m,n) by counting the number of nodal lines along (m) and across (n) the grain.

CAS

INFLUENCE -ON OF

Wales,

of However,

Q-values Q=f/df,

range

modes, modes, 14 NL Nov. 1983

orientated in the direction of the bending. Modes which the plate with 5 mm high cross-grain involved twisting - struts), and the (0,2) as well as bending were less influenced by and (0,3) modes exhibited the highest Q-values the presence of the struts. Adding The over 100 struts across the grain other modes took intermediate values in the range to produced the largest perturbation ' 80, depending on 15 in mode frequencies. the amount of bending of the mode alone or The across the grain. resonant frequencies, of 'beam' modes are proportional square to the root of the flexural rigidity Plat 3 Free-Free Modes of a Guitar Top Plate y«,L !', the atter being equal to the Product the Young modulus (E) and the moment of inertia of the plate Let us iip>. When the struts are glued along the now consider the modes of vibration of a grain, Ip is freely-supported guitar increased by an additional contribution due plate. I recorded Chladni patterns to the moment of of the inertia of the struts (Is). For these modest-sized free-free modes of a guitar top plate at the IP is greater struts, following stages of than Is and the perturbation in frequency is its construction: in its unstrutted 8 state; after cutting the 311 th Ugh the cont^ b"tion of is increases soundhole; after adding seven fan rapidly-i^rwithl^ increasing? ° strut height (h) struts 'along' the grain; after adding three ' because Is behaves cross fully-shaped as a cUbiC polynomial in h. In principle, struts and two struts 'across' the grain; and possible it should be after shaping to calculate the frequencies all nine of the fan struts to complete resonant of the 'beam' plate. Experimental the modes, but calculated values of procedures were the same as described Is for eccentric struts are in previous always too high because they assume the section. The plate was made of high-quality that the middle surface spruce and had a lan inextensional surface about which Ip constant thickness 2.9 mm. Measured calculated) and Is are material properties were E||=922s lies in the centre of the plate (Kirk 1970). MPa, Ej_=9oo MPa and p=l»2o When the Kg ma. The strutting pattern is shown in Figure struts are glued across the grain, the situation is 2c. quite different. Because of the anisotropic nature of Cutting the soundhole had very little effect on Es may be a factor any of 15 or 20 times greater than (the of the modes investigated. the mode frequencies Young modulus of the plate and shapes across the grain). The flexural shown in Figure 2a, which shows the first 12 3 th m 5 * e1 is then much greater than modes of the unstrutted plate including the soundhole, are SS nlLf^ rigldityt

e 2 and Fv^ - Patterns frequencies of the modes of (a) an unstrutted guitar plate, and (b) the same plate Tk hladni VattSTnS WeTe made on the Figure 2d which shows the f strutted plate except for fTJ^M Ti^/S"^(0,3) mode of thei strutted plate. Sketched mode shapes and frequencies in brackets shZn were obtainedfrom finite element analysis. The strutting system is shown in Figure 2c

CAS #40,

/„x of

fan

wood, R, Therefore,

liCh

of i6S fan "«

*v, of

for NL #40, Nov. 1983 15

(a) 37 Hz Hz Hz 120 Hz 146 Hz (b) 40 Hz Hz -v-67 Hz 130 Hz 159 Hz

:") 225 Hz (251 Hz) 243 Hz 293 Hz (306 Hz b) 255 Hz (307 Hz) 264 Hz 365 Hz (331 Hz

Figure 3. Free-free modes of a strutted guitar plate. Mode shapes were computed by means of finite element analysis. The figures show the first ten modes of the finished plate. The mode frequencies shown were determined experimentally except shown brackets, (a) for those in Mode frequencies in the finished plate, (b) Mode frequencies in the same plate before cutting the fan struts to their finished shapes. these modes are related to the earlier set. Rather than Helmholtz air resonance (Dickens 1981). Other show Chladni patterns of the modes, reproduced I have experimentally-observed coupled modes are discussed by results from some finite element analysis which was carried Richardson and Roberts (1983). out in a successful attempt to model the normal modes of the plate described here (see Richardson and Roberts 1983). Fixed-plate modes are not easily studied by means of These results are more useful than simple Chladni patterns Chladni patterns because the plate is more difficult to because they not only indicate the positions of the nodal excite than when in its free state. Therefore, I have used lines but also the bending of the plate. Experimental speckle interferometry and holographic interferometry (see results of mode frequencies are given below the figures for Vest 1979) to make the following measurements on a guitar the finished plate (Figure 3a) and for the plate with top plate after it had been glued to a set of back and rectangular fan struts (Figure 3b). sides. The results shown in this section were, unfortunately, not made on the same guitar plate as The cross struts allowed twisting to occur in the described previously. However, these results are typical of upper bout, but they did not allow bending across the grain. the changes in mode frequencies and shapes which occurred in The prevented pure cross-grain struts the formation of that plate during the remainder of its construction. We may "beam' modes because the flexural rigidity of the composite briefly summarise these changes as follows. After the plate plate was very high and bending across the struts would not has been back sides, the edges the (above Hz). fixed to the and of have occurred until much higher frequencies 400 plates are rebated and the purflings and bindings glued in Cutting the (14 cross-struts from their rectangular form mm place. The fret board is then glued to the neck and upper by 6 mm) to finished form on their had practically no effect bout. Neither of these steps causes appreciable any of these 'low-frequency' modes. HoweveV", the sizes of perturbations in the frequencies or shapes of the modes. the are completed cross struts important in the instrument. However, when the bridge is added, many modes are affected The strutting system was essentially a Torrers pattern as described below. Adding the strings and polishing the instrument produce only minimal changes the modes of with seven fan struts 'along' the grain and two fan struts to 'across' the grain (Figure 2c). These two different classes vibration. of 3truts can be used to control the frequencies of modes The acoustical Importance of the bridge is often which involve either bending along or bending across the overlooked. It is clear that the addition of a stiff grain as discussed in the previous section. However, I was element across the grain must necessarily modify the modes surprised to find that the frequency of the (0,3) mode (the of the plate. Figure 4 shows interferograms of T(n,l)-type sixth mode of the strutted plate) could be adjusted by modes before and after the bridge was glued in place. Modes removing wood from either type of strut. We must presume of the fixed plate have been categorised as T(m,n) by that the cross-grain struts create regions increased counting half-waves across the grain (m) and half-waves areas. along (n) stiffnessi which force nodal lines to form in, these the grain over the entire top plate, though any Removing wood causes a change in both the frequency and the activity in the upper bout is often ignored. The addition shape of the mode. of the bridge increased the frequencies of the T(n,l)-type modes, for n>2, by about Bending' of the plate tended 4 Modes of a Fixed 50?. Guitar Plate to occur at preferred points, at the intersections of the bridge tie block and bridge wings and the Intersections plate When the is fixed to the back and sides the new of the bridge wings and plate. The maker could tune modes boundary condition generates a completely different set of relative to one another by modifying the dimensions of the plate modes. Furthermore, we also introduce coupling different parts of the bridge. The addition of the bridge between the top plate and the back, sides and internal air did not have a substantial effect on the frequencies the cavity. The most important manifestation of this coupling air mode (A0) or the T(1,1) or T(2,1) modes, which implies is a resonance triplet the occurrence of in the that the bridge added comparable amounts of 'mass' and low-frequency response of the generated as a guitar, result 'stiffness' to these modes. Figure 5 shows a selection of of coupling between the top plate plate, the back and the T(n,2)-type modes; the frequencies of these modes did not vary very much when the bridge was added because the bridge was glued along an existing nodal line for these modes.

CAS

%66

e.g.

of 16 NL #40, Nov 19!

Figure 4.

Time-averaged holographic interferograms of top- plate modes of a guitar (Guitar BR9) before and after adding the bridge. The accompanying graphs show the bending of the plate across a line drawn along the bridge saddle. Mode frequencies are shown on the graphs.

These interferograms show most of the top-plate modes splitting its resonant frequency. Observations made on in the frequency range 90 Hz to 1200 Hz. The most notable other guitars show that like all T(n,2)-type modes, the omission is the T(1,2) mode (see Jansson 1971). This mode frequency of the T(1,2) mode is little affected by the generally has a nodal line running across the grain in the addition of the bridge. region the bridge and an antinodal area over the lower cross strut. My results for this mode were ambiguous The back and sides the guitar produce an because the 'plate' mode coupled to an internal air mode essentially fixed boundary for nearly all the top-plate

CAS

of of CAS NL #40, Nov. 1983 17 should note that small variations in the material properties of the plate are likely to have a greater influence than moderate changes in the design of the fan-strutting system. It is interesting to consider the relationships between the modes of free and fixed guitar plates. To my knowledge, guitar makers have no tradition of tap toning, though there have been some recent experiments to assess the value of tuning certain free-plate modes of the guitar (Dickens 1976). There must surely be relationships between the modes of free and fixed plates, but they may be so complex that they are of no practical use. Even so, a maker might be able to establish empirical rules for free-plate tuning so as to produce instruments of a consistent quality. However, these rules are unlikely to be universal and they would probably only relate to one shape of plate. Even factors such as the widths of the linings might be important. I have not had much opportunity to test plates under both free and fixed boundary conditions, but In the limited tests which I have carried out I had come to the 1066 Hz 1183 Hz conclusion that the frequency the (0,3) mode of the free plate (Mode 6 Figure 3) was a good predictor Figure 5. Time-averaged holographic of of the interferograms of T(1,1) mode of the completed This free-plate T(n,2)-type modes a guitar top (BB9). instrument. of plate mode is the one on which Dickens concentrated in his experiments; the can join modes. Therefore, two lower nodal lines be made to the frequencies of the modes are largely into a ring and produce his 'ring-and-a-half mode. unaffected by way guitar the in which the is held, assuming However, the results presented in this paper contradict this that clamps are not applied to top plate the The conclusion. We note from Figures 2 and 3 that adding the major exception is the middle resonance of the low-frequency cross struts reduced the frequency of the (0,3) free-plate resonance triplet. " This mode has nodal lines which are mode, but in the fixed plate an increase in the height inset on the top and the plates. back Both plates vibrate the struts Increases the frequency of the T(1,1) mode. To in the same linear direction and induce considerable motion obtain accurate predictions about the modes of the fixed of the sides. The activities the plates at the middle plate, the maker would probably have to use higher resonance are usually greater than at the upper resonance free-plate modes which involve bending across , the cross (shown here as T(1,1) guitar the mode), but in this the struts as well as the struts. Unfortunately, higher situation was reversed and the upper resonance was the modes increasingly more to isolate and strongest; become difficult this effect was a consequence of the relative excite. On a final positive note, there is one very good tuning of the plates. An interferogram of the mode is not use for the free-plate modes: the 'beam' modes of the shown. It had a frequency of 218 Hz in the freely-supported unstrutted plate can be used to obtain surprisingly accurate instrument and like the other two members the estimates of Em and If the density of the plate is frequency triplet, Ej_. low- resonance its frequency was not known, can Alternatively, tap substantially absolute values be obtained. by the addition of the bridge. toning can be used for comparative tests between plates. 5 Discussion 6 Acknowledgements We have discussed the effects of adding struts along The finite element modelling described in this paper and across the grain on a square spruce plate and on guitar was carried out by Mr Gareth Roberts, and am grateful plates. The greatest changes frequencies are I most in mode for his help in this work. Musical acoustics research brought about by adding struts across the grain, and we must at University College, Cardiff is supported by grants conclude, therefore, that are from the the cross struts and bridge Science and Engineering important strutting Research Council of Great Britain the most elements of the system of a and Royal Society. guitar top plate. the

The above conclusions are supported by our recent experiments with finite element modelling of guitar plates. and ROSSING, T. D. (1983) Ring These experiments have shown that modifying the height of X-modes and Poisson coupling. Catgut Acoust. the fan struts is the least effective way of tuning modes; Newslett. 39, pp. 12-14 small percentage changes in the thickness of the plate DICKENS, F. T. (1976) Tuning of guitar plates. Catgut produce more rapid changes in the mode frequencies of the Acoust. Soc. Newslett. 26, pp. 19-20 fixed plate. By far the most effective way to tune T(l,n)-type modes is by reducing the height of the cross DICKENS, F. T. (1981) Analysis of the and second struts. Finally, we note from the previous section that the vibration modes in a guitar using an equivalent electrical T(n,l)-type modes, for n>2, can be tuned by altering the circuit. Catgut Acoust. Soc. Newslett. 35, pp. 18-21 dimensions of the bridge. JANSSON, E. V. (1971) A study of acoustical and hologram There are, however, other factors which affect the Interferomet.ric measurements of the top plate vibrations of mode frequencies the fixed plate. Our finite element a guitar. Acustica 25, pp. 95-100 modelling has shown that the size the of bottom block is (1970) frequencies of stiffened important. For example, if the bottom block L. Natural is made wider, rectangular plates. Sound and Vib. 13(4), pp. 375-388 the length of the vibrating plate is reduced and the J. frequencies of T(l,n)-type modes increase rapidly. STETSON, K. A. and TAYLOR, P. A. (1971) The use of Presumably, the maker could produce similar effects by normal mode theory in holographic vibration analysis with shifting the position of the lower cross strut. The length application to an asymmetrical circular disc. J. Sci. and width the lower bout are clearly important Instru. (J. Phys. E) 4, pp. 1009-1015 dimensions, which can be used frequencies to control the of (1983) mode 3. RICHARDSON, B. E. and ROBERTS, W. The adjustment mode frequencies in guitars: a study by means I consider that the exact design of the strutting of holographic interferometry and finite element analysis. is less important than the positions of the cross struts or Paper presented at the SMAC '83 conference at KTH, dimensions bridge. At frequencies (below the the low 700 August 1983. To be published in the proceedings. Hz) the fan struts merely add to the overall stiffness of the plate. At higher frequencies, nodes or antinodes often VEST, M. (1979) Holographic Interferometry, John Wiley fall directly over struts suggesting that the maker might be and specific changes frequencies by able to induce in mode (1961) Chladni Figures. A Study in modifying the distribution of the fan struts. to M. D. Symmetry, Ltd. put the usefulness this method into perspective, we Bell and Sons

very

itself.

fan

affected

References

CALDERSMITH, G. modes, Soc.

first

KIRK, C.

G. of fan

of Stockholm, C. Sons

However, WALLER, of 18 NL #40, Nov. 1983

FURTHER EVIDENCE FOR COUPLING BETWEEN PLATE AND ENCLOSED AIR VIBRATIONS IN STRING INSTRUMENTS

G. Bissinger East Carolina University Greenville, NC 27834 USA and C. M. Hutchins 112 Essex Avenue Montclair, NJ 07042 USA ABSTRACT microphone or accelerometer outputs that arise from interior air in four different The string the large numbers of peaks in the spectra. (standard instruments violin, long-pattern In the original work by Jansson [2], Stradivarius model violin, mezzo-violin and 16 identifying the interior air modes, the string viola) 0„ was interchanged with C and instrument was encased in plaster to the F eliminate CCI ? to examine the coupling of plate influence of plate vibrations on the interior air by vibrations to interior gas oscillations shifting oscillations. Here we have no such simplification the frequency of these oscillations. The lowest and we observe that the probe microphone gives frequency air Al and 2, could be modes, A significant outputs when the plate oscillations are identified reliably by correlating results for the strong. We have also observed in general, interior oscillations that, all gases. These gas also when there is strong coupling between air and plate showed significant plate coupling as evidenced by vibrations the accelerometer output and probe accelerometer measurements at three points on the microphone output are large. When the coupling is top plate. very weak the outputs are characterized by large INTRODUCTION dissimilarities in magnitudes, with the ratio depending on the character of the resonance, i.e. plate producing In a recent work we reported on an experiment resonances very low microphone outputs air to determine significance and resonances producing weak plate the of "enclosed vibrations. air-plate" coupling by interchanging the air inside In some cases we have had difficulty in identification of resonance peaks due to the a violin with CO gas The fundamental idea large HJ. number of peaks in of this work was to or not interior occurring certain frequency show whether the regions, iri particular gas oscillations significant plate above about 700 Hz. This could force made vibrations. Using an acoustic driver slipped thru identification of the A2mode difficult for the air and C0 spectra, but for the F„ an f-hole into the lower bout a probe 2 CC1 2 spectra the A2peak was below the microphone slipped through the other f-hole into the "clutter" (probably due to various rib and opposite side of the lower bout and an accelerometer plate, "body" resonances ) and was easily identified. An positioned at three points on the top instrument's additional aid in the identification of the plate, we were able to monitor interior air type mode in the spectra was the relative accelerometer oscillations and plate vibrations. Our results readings at peaks in the plate response curves that clearly showed that the lowest air modes frequency appeared to be associated with interior gas 12], A0and Al , did indeed produce strong plate oscillations. Using the nodal-antinodal patterns vibrations that tracked the downward shift in for the interior gas oscillations from Ref. 2, we resonant frequency associated with the substitution observed that the accelerometer readings for the A of CO for air. We now extended these 0 and Al modes always showed strong plate motion in measurements to include gas interchange with a much the antinodal region and relatively weaker response gas, CCI_F , which will drop heavier the air in the nodal regions. For the A2mode clear resonant frequencies even and introduced a correlations were noted only when the A2mode broader cross section of string instruments to dropped to frequencies below 600 Hz, i.e., only for examine the generality of this coupling for other the spectra. It was then a string instruments. We felt that a quick look at straightforward task to work from the these new results would be useful for those with an spectra back to the air and C0„ spectra. During though interest in this subject, even many of the this identification procedure it was noted that details will have to be filled in later. generally the peak in the probe microphone output associated with the A2mode appeared, relatively RESULTS AND DISCUSSION speaking, to grow weaker as the resonance frequency increased (the mezzo-violin, SUS #159 was the only Since the apparatus and techniques were so exception) . similar to those used, and discussed, previously In this work we are going to restrict ourselves [I], the reader should consult that work for the to "air-plate" coupling fot just the AO, Al and A 2 experimental details. Here we will discuss only the modes, which are primarily a volume mode, a length matters of interest new to this experiment. Since mode and a width mode (lower bout only), the velocity of sound in a gas varies inversely as respectively [2]. In the interest of brevity we will the square root of the molecular weight for that present our results in the Table below for these air gas, for C0„ the velocity of sound is only 0.812 modes in all the instruments. Those interested in a that for air (same temperature and pressure) and for graphical presentation of the air and plate mode CCI-F- the ratio is 0.492. When the air in frequency and response variations under the an instrument is replaced with a heavier gas, the interchange of air and Co_ are referred to our "transit" time for the wave to go from boundary to previous work for the standard violin, SUS #180 [I], boundary inside the instrument is increased. This or the more recent results obtained with extends the period of the wave and so the CCI F for this same instrument [3]. oscillation frequency drops. If the interior gas Referring to Table 1 below we see that the oscillations couple strongly to the instrument frequencies for the AO, Al , and A2modes for the plates, then the frequencies of the plate vibrations various instruments usually fall close to the will drop also. While this seems straightforward, frequencies calculated from Ref. 2, which were for a there are serious difficulties in determining the "standard" violin encased in plaster; the exception exact character of the resonance peaks in the probe was the mezzo-violin. We have normalized the

CAS

AO,

off-center,

have,

further,

CCI„F CCI„F„ NL #40, Nov. 1983 19

TABLE I "ENCLOSED AIR PLATE" COUPLING FREQUENCIES (AO, Al and - ONLi)- A2MODES - All frequencies shown are for air nodes; plate vibrations generally within a Hz pf these The results of this work show clearly that for frequencies . frequencies below 600 Hz, strong plate motions are associated with interior INSTRUMENT MODE AIS C0 gas oscillations, and will 2 2 "track" decreases in interior gas (SUS ■"*) oscillation This Work ?red. This Work ?red. This Work ?red.~ frequencies, i.e., the plate acts very much as a loudspeaker does. What is not clear at present is 180 AO 23 6 264 223 210 350 130 how much of a contribution this coupling makes to 'standard 465 455 33 3 369 229 2 23 the overall instrument. violin ) A2 1047 002 304 SCS 490 380 acoustic output of the Our earlier work indicated significant downward 230 AO 27 6 277 236 225 154 ! 36 for vs. air, in the AO-associated peak (long Ai 37G 47 7 383 333 230 225 tern Strad) A3 1070 1030 33 5 -S3 frequency of the Fourier-analyzed acoustic output of b standard violins; we have seen this same shift for 159 AO 235 251* 236 204 103 we aezzo- Al 433 433 352 352 222 213 mezzo-violins and violas also. Unfortunately do violin ) A3 755 944 767 363 not have any such measurements for CCI„F„ interchange. We also see that the mezzo-violin has 111 AO 234 237 201 192 138 (16" Al 413 308 335 331 201 201 considerably different frequencies for the Al and A2 viola) 33 335 330 0-63 723 413 338 modes, relative to than the violins or violas. If higher air modes are an audible contributor to the acoustic output of the violin, then, on this basis alone, the mezzo-violin will sound different than a standard violin. The interplay between air * - From the work of Jansson [2] with encased normalized to and "plate" modes is still not a question in AQ and Al settled a - evidence for three peaks at Hz. terms of the acoustic output of the instrument, what b evidence thr"ee peaks at Hz. is settled is the matter of coupling between + - predictions based on Al mode only - interior air oscillations and plate motion.

frequencies of Jansson to the A0and Al mode frequencies for all instruments except the 1) Bissinger and M. SUS where only the middle mode G. C. Hutchins, mezzo-violin, (1983) Al was used for normalization. These normalized CASNL 22 , 7 frequencies were then multiplied by 0.812 for 2) E. V. Jansson, CASNL j_9 ,13 U973;; CO and 0.492 for CCl_F_ for comparison Acust. 37 , 211 U977). with these gas-interchanged cases. Again it should be noted that the A0mode always lay above the 3) G. Bissinger and C. M. Proc. predicted for 0„ CC1 F„ Hutchins, values the C and 2 Conf., July, 1983 cases. This effect probably was due to the Stockholm Mus. Ac. (to be published). intermixing of the air and interior gas at the f-holes in this so-called "breathing mode".

##**"*#**"*■*##**#■*###■*"####"#■#

Dear which reflect plate tuning practice, and that would be a vital I believe Jim Woodhouse's article in the Newsletter #39 connection in violin research. But the useful discussion violin Recognising Violins: Starting Transients and the Precedence quality hinges on the relationship between these distinctive indicates an important direction in our understanding violin diagnoses and the violinist's experience of the violin. sound generation and its perception, and I would like to respond to it in two I must dispute Jim's statement that "the steady state spectrum the note cannot possibly such signature First, if we compare two violins using sp'rcato, or independent of the note played - a moment's thought about the violin bowing technique that produces a series string transients without frequency response curves tells us that". I believe that a substantial long steady notes to "wash out" the starting impressions one gains part the violin literature disagrees with that statement, including useful audible signatures distinguishing the violins. More dramatic the Long Time Average Spectra Miller and Matthews work on appear distinctions between violas and violins. electronic and particularly Hacklinger's and Reinicke's work on bridge effects. has only to hear the audible effects to The problem arises when we try to associate violin quality with all notes of the violin when the mute is or even when these distinctive starting impressions. When the violinist proceeds to bridges are changed. If we appreciate that at frequencies above the explore the instrument with hard bowing high on the and D lower body resonances, the resonance peaks occur more closely in strings etc., words like "evenness", "sonority", "ease response" frequency and begin to merge in to a "resonance continuum", which are bandied and they represent him and the listener is likely as much characteristic plate tuning practice (as well as important qualities that he senses or fails to sense in the violin. But wood types, violin pattern and varnish) as the lower resonances, we these expressions of quality can be no more directly related to the may also appreciate that steady notes excite the violin body to starting sounds ("Woodhouse clonks") than to any other diagnositc resonate and radiate a frequency spectrum which the average such as frequency response, long time average spectra or even the profile represents the character the particularly when that eigenmodes of the free plates. That is to say, until we are able to radiated spectrum is averaged by room find out what a good violin is doing right, and a bad violin is doing wrong when the violinist bows the strings, then we cannot talk Without any attempt at a proper discussion of the violin meaningfully about violin behaviour and violin quality. At this frequency response I conclude what I it is stage by presenting consider hard enough to get consensus among violinists about whether a two frequency response measurements, in which the certain violin is "good" (rather than mediocre) although "bad" violins onset of a resonance continuum is evident around 2 KHz. The are fairly uniformly labelled. sound level response profile is commensurate with the driving point response profile, implying that the sound output is a I am not saying that the "Woodhouse clonks" are unimportant simple the energy input, at least at one bridge features the violin sound in the perception process may position. Averaging of the sound level is justified in the very they pressure well serve as vital overtures- to the steady note following. comparison of several sound pressure taken at even They responses equidistantly may be direct features of the lower frequency body resonances various positions around the test violin.

CAS

fell few

CCI,F

shifts, CO„ pat-

158/166 718/740 418/429

AO,

violin, nodes, 262/276/290 for 276/285/303

REFERENCES

#159,

Editor,

C.A.S. of "On any of Effect" of

ways. Second, of convey any martele, any of of studies, simulation, One attached,

scales, G few of about, for of

of of violin, reflection.

here, useful formats for

average average function of foot of 20 NL #40, Nov. 1983

Comparison responses made with two violins at both bridge I hope this sort of discussion is progressive positions (which be regarded as the principle points strings to body via bridge) are Yours sincerely, 48 Den diagnostics distinguishing violins. These measurements LATHAM. 2615 are essentially similar to Jansson and Morals' violin responses taken with a different system and show the several prominent resonance peaks below 800 Hz which are probably important in the "Woodhouse

CAS

of foot may of transfer from energy useful ny Street, for different Graham Caldersmith A.C.T. AUSTRALIA.

Clonks" CAS NL Nov. 1983 21

ANALYSIS OF SOUND SPECTRA FROM BOWED' VIOLINS AND VIOLAS

P.Barnes, P.J. Chandler, S.Fredin, G. Hammel, P.D.Townsend, H.J.Whitlow and L.Wilzen

School of Mathematical and Physical Sciences, University of Sussex, Brighton, Sussex, BNI 9QH, U.K. INTRODUCTION

In any quantitative study of the performance the effects linked to the asymmetry of the vio- of an instrument one requires a reproducible lin. (In the framework the bow stroke is hor- method of generating the sound as normal play- izontal and the instrument is inclined). ing by a performer is inadequate for repetitive or controlled measurements . For the violin The main advantage of the computer graphics family the most realistic method of excitation is that a great wealth of data may be presented is with a bow since this generates all the as isometric plots of three variables (e.g.in- forces and spectrum of notes which result from tensity, harmonic content, fingering position) the sawtooth-like action of a string pulled or as contour plots of the isometric views. and released by the rosined hairs. Alternative As will become apparent the isometric projec- methods using mechanical excitation with a tions are visually interesting and one can di- transducer pushing on the instrument or an e- rectly sense the major such as the lectromagnetic coupling to the strings are con- difference between up and down bowing, but venient for response measurement of simple sine this is not useful for quantitative analysis wave excitation 1-3 . However the violin is a- and one must use the views to select simpler symmetric and probably non-linear in some of two-variable graphs. its responses, therefore a simple excitation by a pure sine wave may not reveal the full com- AIMS OF THE PROJECT plexity of the performance of the instrument. The present paper demonstrates this asymmetry At this stage of the project we are still to bowing by noting that the response to up comparing the effects of very simple changes and have followed and down strokes differ.

EXPERIMENTAL SYSTEM I) intensity versus bow speed at constant pressure , To preserve a semblance of normal playing II) intensity versus pressure at constant we have developed a mechanically bowed system bow speed, suitable for violins and violas in which we III) harmonic content as a function pres- have control over the bowing speed, bow pres- of and bow sure, position of the bow and the note fin- sure distance from the bridge, gered on the string. The apparatus is con- IV) harmonic content with a mute, tained in a small room with foam and carpet V) sound level curves (total power) for covered walls (but not anechoic) and the sig- notes on each string, nal is taken from a microphone some 4 feet a- bove the bridge on the G string side of the VI) effects of damping air resonances, violin. Sound intensities were originally an- VII) isometric presentation of harmonic con- alyzed point by point with a tuned amplifier tent for a range of but rapid analysis is now made with a Hewlett VIII) some differences between up and down Packard (HP) spectrum analyzer. This gives a bowing complete harmonic analysis for each bow stroke. . The sweep is triggered after an adjustable de- The data in these initial surveys have main- lay to register the same part of the bow stroke ly been used to establish the experimental and ensure the uniformity of the signal. For technique and obtain reproducibility and we convenience the HP signal is fed to a multi- have only worked with 2 violins, 2 violas and channel analyzer and signal averaging is pro- a large viola. Brief comments on these early duced by making several bow strokes. This in results are however instructive. turn is read by a Superbrain microcomputer and linked to a VAX computer for graphics presenta- BOW SPEED, PRESSURE AND POSITION tion. No room or frame resonances were noted. I) At normal bowing pressures and speeds we The sound level curves (i.e. the total pow- found the total intensity was proportional to er from all frequencies) can be read from a bow velocity for a fixed bow pressure. flat response amplifier or by integration of the HP spectrum. The two methods are in good II) and III) Both bow pressure and bow po- agreement. One notes in the results presented sition change the harmonic content of the notes here the instruments were not bowed for maxi- played. Increasing pressure does not uniform- mum power. When maximum loudness was tried ly increase the power in all the harmonics and there was a change in the harmonic content instead the total intensity increase Is achieved which suggested such a measurement is unrepre- with changes in the relative strengths of the sentative of normal violin playing. components. For many combinations of position and bow speed the intensity reached a plateau The response of the cham- characteristics which is not very sensitive bow ber influence the signal but to additional by leaving the pressure. The total intensity of position up and down microphone unchanged one can readily bows can differ by a few dB for make comparative studies. the same bow A refinement is to position and pressure. In some cases analyze only up or down bow strokes as two increas- the ing pressure produces a fall in total intensity, directions do not produce identical harmonic but this was not of great practical as spectra. The interest difference is due to the instru- it was accompanied by a very unmusical sound. ment, not the bow, as reversal of the bow gives

#40,

L.Cooke,

effects,

fundamentals, 22 NL #40, Nov. 1983

THE EFFECT OF A MUTE and 317 Hz for wood in the case of damped IV) The addition of a mute reduces loudness strings. We found that the detailed sound lev- and produces a softer tone quality which is el curves for the various strings gave simi- caused by suppression of higher harmonics. This lar resonances although the relative intensi- was confirmed in the present apparatus and fig- ties differ from one string to the next. ure 1 shows a bar diagram for the open A string of a violin with, and without, a mute. The to- Note that the ear is not a flat response tal power level is reduced by 50% but one notes detector and is biased towards harmonics near the first two harmonics are little changed. 1000 Hz. Thus although the total intensity Therefore the perceived intensity change is curve gives a weak maximum near 317 Hz one can based on an auditory signal integration rather understand the increased apparent importance than a conscious response to the fundamental. of this fundamental when one notes that for it the analyzed harmonics were strongest near 1 950 Hz.

With sound level data from the mechanically bowed instrument the air peak is placed near 225 Hz, in reasonable agreement with the maker's value and in the range of other viola air resonances . The bowing method show maxima near 276 and 305 Hz but these seem low in frequency for a wood resonance and stronger features are detected near 370 and 393 Hz In line with other published values. (One should remember that a peak in the total intensity curve does not guarantee a resonance at that frequen- j 2 3 4 5 6 7 Harmonics cy, as will be documented in VII). Figure : content for a 1 The harmonic violin A string AIR AND WOOD RESONANCES with (open) and without (hatched) a mute. The total power is reduced by 50% VI) Separation of air and wood resonances has previously been attempted by changing the MEASUREMENTS OF THE SOUND LEVEL gas within the instrument body since a change V) Initially, sound level curves were re- in sound velocity will alter the resonance fre- quency5 In the present series of corded at semi-tone intervals but it was noted . experiments a method of the that many of the resonances detected were so filling f holes with strips of soft foam was well defined In frequency that closer spaced tried. The results are not sim- as does measurements are needed. ple to interpret not only the foam reduce the sound level curve near the Helmholtz Figure 2 shows a set of intensity curves air resonance but significant reductions occur for one of the standard size violas (viola L) in sound level across the entire range of notes made for this experiment by Mr. D. Mills. The being played. For one violin strong resonances instrument has a good tone' ' and the plates near 270 Hz (the classical Helmholtz air reso- gave eigenmodes 2 and 5 at 109 and 230 Hz for nance), 740 and 900 Hz were suppressed whilst the front and 88 and 231 Hz for the back be- others were only reduced. fore assembly. The air and wood resonances assessed by the maker by blowing across the f In another standard size viola, Mills (D), holes or listening for pain threshold with a the air resonance is placed near 225 Hz. Foam stethoscope (!) were 215 Hz for the air and 2i287 filling of the f holes removed this peak in I I I I the sound level curve. Elsewhere the sound C 3 Gj DA A 4 level curve was generally suppressed by from r^ (^ h^ FIRTH 10 to 20 dB. Many of the sound level maxima still but their relative inten- --■*- are apparent I AIR I I sities preclude an immediate association with 10 - |*| - cavity resonances. The coupling between different resonances is complex as for the D " I^D string the 500 Hz intensity maximum increased 12 dB for the foam filled f holes, whilst that at 380 Hz dropped 23 dB.

5 uj i 1 l We differ from Caldwell in attributing gf II ||| '^-A higher frequency dips in the sound level curve to sympathetic string excitation rather than to some type of air cavity mode (see section VII). Figure 3 gives an example for a Mills super^size viola (20 inch) made to the C.A.S. model. The air resonance is normally near the frequency of the G string and one may la- | bel resonances air, wood and wood prime as in- 0 I I I I I I I L_ dicated. the f holes the 100 200 500 400 500 600 700 800 900 1000 Blocking suppresses Hz Helmholtz resonance but additionally reduces Figure 2: A sound level curve for a standard size Mills other features of the sound level curve and viola (L) . Similar features are noted on small frequency shifts are noted. each string. The lowest notes on the D and A string produce more power (dashed lines) (+) It was placed first for tone in Facta than equivalent notes played on the G and D Brlttania . strings. For comparison typical resonances labelled as air, wood and wood prime are indicated (see text) .

CAS

MILLS

STRING

STRING NL Nov. 1983 23

Unfortunately these data emphasize the complexity of the problem rather than ex- plaining the changes but they do indicate the need for harmonic analysis rather than the simple sound level measurement.

HARMONIC ANALYSIS

VII) The major weakness in interpreting sound level curves is that a strong signal does not imply a resonance at the frequency of the excitation. Conversely a reduction in signal does not give evidence for a reduction in the fundamental intensity. The Figure 3: example In Sound level curves for the C and G strings of part IV for the of a mute showed that the large (20 inch) Mills viola are shown. effects the integrated intensity of all the Air resonances were suppressed with foam in harmonics bore little relation to the effect of the the f holes and the reduced curves are shown change in the fundamental. Indeed for the as dashed lines. The air resonance G near 3 2nd harmonic at 880 Hz there was a 10% in- dominates the loudness signal near 200 Hz. crease in signal whilst the total Note unassembled were intensity plate resonances mea- dropped 50%. sured at 110 and 193 Hz for the back and 108, 173 and 214 Hz for the front. The simplicity of sound level curves must therefore be viewed in conjunction with de- In more detailed harmonic analysis of the tails of the harmonic content of each note 20 inch viola we found that the strongest har- that is being played. This is most appropri- monic of the C string was the 2nd harmonic al- ate for a bowed violin as the act of bowing though there a is reasonable component from provides a waveform in the string which con- the fundamental. This is in contrast with tains a mixture of many harmonics. For ex- measurements of standard size violas which ample if the string undergoes an idealized give negligible emission at the C string fun- sawtooth vibration the power damental . fed into the harmonics is in the ratios 1:1/4:1/9:1/16, etc. The interpretation A more realistic string motion, togeth- is not simple as the har- er with coupling between monic pattern is not determined simply by the resonance modes in the instrument, can readily change violin/viola body but by the entire instrument. the excitation pattern. The mode This is shown quite dramatically in figure coupling problem re- 4 mains even if sound level are where the harmonic pattern for the open curves attempt- four ed by a sine strings of the 20 Inch viola are contoured. simple wave excitation. The harmonic content is particularly sensitive to The original A string was weak compared changes in efficiency as only some 1% of the with the other strings and as shown by figure mechanical energy is emitted as sound. To pre- 4a, there is negligible emission at the A string sent the data we have used isometric projections, fundamental. Changing to a heavier gut A as in figure 5, or contour maps of the intensi- string produced emission at 440 Hz as expect- ties, as in figure 6. ed. However the change in the type of A string has had a profound effect on the har- Figure 5 gives the visual description of the monics of the C string (fig. 4b) with en- harmonics and their intensity variations for a hancement of the third and fourth har- series of notes on the C string of the standard monics. The seventh harmonic of the G is al- size Mills (L) viola. clearly the same so increased.

1 1 1 I I L I 1 I I L J_ I J J I M String f ll> ')» A( steel)

-) 1 1 1 1 1 1— i 1 1 1 1 I—i1 —i r—i—i .0 .2 .4 .G .9 1.0 1.2 1 .4 I.G ..;'" Figure 4:4 : Open string contocontour maps for a 20 inch viola with (a) a metal A string and (b) a gut A string. Note changescha in the C string harmonic intensities as well as for the A string

CAS #40,

first, Quite 24 NL #40, Nov. 1983

Figure 5 sities of a series of notes played on 5 «- string of the standard size Mills viola (L) . pattern of harmonics is not preserved for all the fundamentals although most of the power is OPEN STRING HARMONICS generated within the first four or five harmonics. The instrument produces little power from A the C string in the range 2000 to 3000 Hz but are some stronger high harmonics above the D there I 1 1 10th. Figure 6 gives a partial contour plot of sequence of har- G the isometric picture and the 1111 I I I monics curving across the graph is visible. The curvature is because the fundamentals were chosen in steps of equal length along the string On the figure the sound level curve is plotted (as in figure 2) which is the same form as the integrated signal of each spectrum. In figure 6 a smaller range of frequency is plotted. sig- A detailed analysis of the sound level for nal of figure 6 reveals further surprises, example: (a) The- signal from the open C string contains a trace of the fundamental at 131 Hz but most of the power is appearing at non-harmonic peaks near 280 and 415 Hz. These two peaks produce a very strong sound level signal for an apparent fundamental of 138 Hz. The strong 280 Hz resonance was detected by Mills and is claimed by him to be the main wood resonance. Previous interpretation of sound level curves would place the wood resonance higher in frequency near the 370 to 400 Hz sound level maxima I*.1*. The origin of the 415 Hz signal is not obvious . Figure 6: A contour map of the intensities of harmonics for the data of figure 5. Sketched on the figure is the sound level curve for this viola (as in fig. 2). The position of the harmonics of open strings is shown. Low points in the contour plots reflect power absorption by harmonic coupling to the open strings (e.g. at 588 or 1176 Hz). Note the fundamental does not contribute significant- ly to the intensity curve for notes below A 3 .

CAS NL #40, Nov. 1983 25

second harmonic of the open G string. Whilst (b) For many of the lower C string notes for playing the same frequency range on the G string up down bow strokes a both and resonance near the dip is less pronounced (see fig. 2) and the Hz is which is unrelated to the 150 stimulated strong resonance of 370 Hz is one third that of fundamental but is strongest when the Hz 415 the same feature on the D string. For bowing resonance is weak. in the frequency range 350-400 Hz, the power (c) The fundamental is of, negligible impor- is dominated by emission of the fundamental which is a basic resonance of the instrument. tance below about 210 Hz ( A 3 ) which is the Helmholtz resonance of the air cavity. How- Power absorption by undamped strings is like- ever the sound level curve at the 225 Hz point ly if harmonics of the string and the played coincide of loss reflects both a powerful fundamental and a ba- note and, course, greater sic resonance. The 225 Hz resonance is accom- occurs if two string harmonics coincide. Such panied by a strong 900 Hz signal. minima are visible in fig. 6 near 587, 784, 908 and 1174 Hz. In each case the appropriate (d) The presence of the powerful air reso- harmonic is suppressed. Hence in the summa- nance pulls the signal and at an attempted fun- tion or signal level measurement the total in- damental of 222, strong features appear, fig- tensity is relatively weak and could account ure 7, at 200 and 236 Hz as well as at 222 Hz. for the power drop for fundamentals near 196 A second example occurs for the D string play- and 380 Hz. Close to C+ (261.6 Hz) the 2nd, ing 376 Hz which gives a broad 'fundamental' 3rd, 4th and sth harmonics are all weakened as with a peak pulled to 400 Hz and a second'har- they match other string harmonics. monic' at 765 Hz whereas higher harmonics are as expected. In a more detailed study of the power transfer from notes on a viola A string we obtained, figure 8, a contour map with 'missing' frequencies at 588, 1176, 1960 and 2352 Hz. As seen from Table I these are precisely the regions expected for power transfer from the A string to the three open strings. To test this model we have wrapped foam around the open strings to stop them radiating power directly into the air. The new contour map looks very similar to that of figure 8 but on closer inspection the signals near the 'dip' frequencies are found to be even weaker. This gives a consistent model of the process in which, for the normal condition, power is transferred via harmonics to open strings and a fraction of this energy is subsequently re-emitted by the open string. On damping the open string this secondary energy is lost so the dips are even lower .

u o 500 1000 1500 2000 Hz igure 7: An example of frequency pulling by strong resonances. The viola (L) was played at 222 Hz but strong emission is noted at both 200 and 236 Hz in the 'fundamental' with corres- ponding features in the higher harmonics. The air resonance is centered in this frequen cy region. (c) Power transfer can take place between strings if the harmonics of the note being played match the harmonic frequencies of the other (open) strings. Such power transfer can reduce the intensity of the played note as the energy may not be re-emitted from the open string. Such an effect for damped and undamped strings has already been reported "

In the present data of figure 2 there is a notch in the intensity curve between the closely spaced peaks at 185 and 197 Hz. These data are recorded whilst playing the viola C string and it is suggested that the double "resonance" feature is an artefact of power absorption by the open G string. In principle the Instru- ment has a powerful 'wood prime' resonance ex- tending across this range. Figure 8: Contour plots of the viola (L) played with up bow strokes on the A string. Power loss to Where two strings couple to the system can undamped strings is noted as, for example at the dips even more pronounced. exam- are For 588 and 1176 Hz, there can be with a resonance ple there is deep valley in the loudness harmonics to 2 or 3 open strings (see Table 1). curve at 380 Hz (near Gi+) when the D string is being played. However, this frequency closely matches the 3rd harmonic of the open C and the

CAS NL #40, Nov. 1983

Figure 9: Isometric plot of the harmonic content of notes from viola (L) A string. A difference between up and down bow strokes is apparent. TABLE 1

Coincident open string harmonics of the viola strings Note that interaction of the open strings (e.g.C,D,G) CONCLUSION interfere most strongly with notes bowed on the other this preliminary study has em- strings (e.g. A) when several harmonics In conclusion coincide. Fre- phasized the need to measure the harmonic con- quencies in Hz have been taken from a tempered scale. tent of a bowed note, rather than just the sound level. Power absorption to undamped strings is C string G string D string A string surprisingly effective in removing power from appropriate resonances and some differences in (131) (196) (294) (440) bow direction were noted which are perhaps not 393 392 unexpected for an asymmetric instrument. For 588 588 was a strong contribu- 786 784 the viola C string there tion from non-harmonic resonances. 882 880 1178 1176 1176 The additional information in the present a- 1568 1568 nalysis is at first sight overwhelming but an in- 1764 1764 1760 telligent pattern is now emerging for a wider 1961 1960 frequency range as the effects of high harmonics 2358 2352 2352 are included and power losses as well as reso- 2640 2640 nances are considered. OF BOW DIRECTION REFERENCES VIII) As a further example of an isometric 1 J.Audio Soc. 1973 plot of the response of the viola, figure 9 CM.Hutchins, Eng. 2J, 563, shows the pattern generated on string the A of I.P.Beldie, 22, 13, 1974 the Mills (L) viola. Up and down bowings are 2: CASN visibly different in the production of harmon- 3 C.Gough, CASN 35, 22, 1981. ic content. The contour plot of the up bow strokes, shows power absportion open to strings, 3 I.Firth, Phys. Educ. 9, 479, 1974 and non-harmonic signals near 236 Hz (i.c.from the air resonance?) Note the open A string 5 C.L.Caldwell, JASA, 36, 1025, 1964 power comes from the second harmonic. Down bow strokes generate similar features. ACKNOWLEDGEMENTS The 236 Hz resonance strongly perturbs the We are most grateful to Mr. D. Mills for the excel- emission pattern of the lower notes of the C and G strings. The C string also picks out a lent violas that he has made for this work. His con- resonance at 200 Hz. As shown in figure 7, tributions to the physics are also appreciated. mode pulling to both 200 and 236 Hz occurs and a signal at 360 is visible, and the sth and Bth harmonics have some structure.

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EFFECT NL #40, Nov. 1983 27

BOWING EIGENMODES ON FREE PLATES only needs a method of supporting the free plate on four points coinciding with the nodes Emery Julian of the particular mode one wishes to excite. shire, Corsley, Nr. Warminster, Wilt U.K. Four erasors of the kind that push on to the end of a pencil make very convenient low damp- For the past nine years I have been tuning ing supports when applied to dowels which can the plates of violins, violas and cellos us- be pushed into a base board in various posi- an oscillator to drive the modes in the ing tions. The plate should be sufficiently sta- manner recommended in numerous articles in ble to enable a heavily rosined bass bow to be the Newsletter. During the course of apply- drawn across the edge while a finger is placed ing these techniques, I have found it useful on a node of the mode to resist the bowing to assess the modal behavior a sim- using very pressure. The bowing positions for modes one not any ple method which does require electron- and two occur at the same points at which the ic apparatus. If one is not too concerned a- modes are normally driven by the speaker. With keeping records of frequencies bout precise it a little practice one can learn the best angle is quite possible to apply to this method the of attack and pressure to apply. One will hear of tuning as advocat- general principles plate the note of the frequency of the mode one is ed by Hutchins. one familiar Carleen Once is looking for. It is a good idea to listen to with the of modes and nature one, two it the tap tone first so that you know the fre-

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five, NL Nov. 1983

quency to listen for. When this is obtained, it helps just to mark the bowing and touching positions. Then after a few practice strokes to get the feel of the bow, one needs only to lightly sprinkle glitter or fine tea leaves before repeating the bowing procedure until the modal shape is clearly visible. The ring mode on the front is usually found more easily than it is on the back. But if bowing proves difficult one can use a glass rod which is placed on the centre of the plate and vibrated by a wet finger and thumb. From this brief description it should be clear to anyone familiar with Carleen Hutchins plate tuning methods that the assessment of plate behavior by studying the shapes and frequencies of eigenmodes is not a technique which is solely dependent on the technology of today.

STROBE VIEWING OF MODES

It is rather interesting to observe the nature of a plate's bending while it is being excited electronically. This is possible by di- recting the light from a tuneable stroboscope on to the active plate and adjusting the frequency of the strobe so that it is a few Hz removed from the mode frequency. Modes one and two present a very dramatic effect as the plate twists and flexes. Five can be observed bending to a lesser degree. It could be that this is a technique which would enable one to locate the actual bending areas of a particular plate and this would facilitate the selective thin- ning of these areas when applying the procedures referred to in "PLATE TUNING FOR THE VIO- LIN MAKER" (Newsletter No. 39, May, 1983).

PHYSICAL MEASUREMENTS ON SAMPLING OF EUROPEAN SPRUCE AND MAPLE FOR VIOLIN TOP AND BACK PLATES

Morton A. Hutchins*

Background for the work of this paper goes of this to in back to studies made on the mechanical proper- to use the results testing help and for the con- ties of wood starting with those of Barducci the selection of spruce maple and Pasqualini published in 1948. * Data from struction of other instruments. this study was charted by J C Schelleng in . . Rectangular strips of both spruce and maple 1963 2 to show the relationship of other woods to determine the following prop- to the Norway spruce and maple, conventionally were measured used in the making of musical instruments of erties: family. recently Daniel Haines 3 the violin More Density Kg/m 3 studies of woods selected P has made extensive Vibrational damping Reciprocal of damping for the primary components of musical instru- Young's Modulus E Mega Pascals In 4 we reported on the testing ments. 1981 Velocity of sound C Meters/second and of 9 different kinds of wood comparisons Radiation of ratio R C/p which were built into the back plates of 9 inch violas 1 6 . Our test methods were those described previously. 4 All test strips had a cross section The work here has consisted of test- reported closely approximating 1.25 cm x 0.400 cm. Length ing and determining the parameters of wood se- varied according to size of wood samples avail- lected from one shipment of commercially available able European spruce and maple used in the top . and back plates of 10 violins which are cur- Three measurements were taken of the funda- rently under construction. When these violins mental frequency of vibration: the frequency are completed we intend to relate the date ob- at resonance (fo), the frequency below reso- tained from the tests to the characteristics nance at which amplitude is half-power (3 dec- of the instruments. It may also be possible ibels down from peak) (fL ) and frequency above resonance at which amplitude is also 3 dB be- This paper was presented at the Catgut Acoustical Society low peak (fh) " *International Conference on Musical Acoustics held at Northern Illinois University, DeKalb, 111.,April 23-26,1982

CAS #40,

Q NL Nov. 1983 29

AND MAPLE - 1979 - E YOUNG'S /El - Spruce Kilograms Mega Pascals ' Ell Maple 3 Meters/sec. . per E - meter Q R = c/p '*- #260 p 11 I 1 II 1 II 1 Spruce 414 12800 1020 5580 1560 175 63 13.5 3.8 12.5 Maple 585 13500 1695 4710 1740 137 50 8.1 3.0 7.9 1.58 (1) #262 A

Spruce 437 13600 880 5680 1390 187 60 13.0 3.2 15.5 Maple 563 11800 1960 4630 1840 131 51 8.2 3.3 6.0 2.58 m #263

Spruce 441 15800 708 5950 1270 189 62 13.5 2.9 22.3 Maple 59k 9750 1570 4060 1620 100 46 6.8 2.7 6.2 3.60 (3) #264

Spruce 15100 937 5880 1480 190 65 13.7 3.5 16.1 Maple 570 12700 1780 4720 1750 151 57 8.2 3.0 7.1 2.27 (4) #265

Spruce 477 17800 1000 6040 1460 208 52 12.6 3.1 17.8 Maple 601 7900 2060 3650 1840 91 51 6.1 3.1 3.8 4.68 (5) #266

Spruce 414 10350 977 5110 1500 170 66 12.4 3.6 10.6 Maple 605 11300 1510 4330 1570 131 56 7.1 2.6 7.5 1.41 (6) #276 B

Spruce 417 14300 1170 5770 1690 176 60 13.8 4.0 12.2 Maple 582 13700 1810 4850 1750 156 52 8.3 3.0 7.5 1.63 (7) #268

Spruce 494 17300 1130 5920 1510 187 58 12.0 3.1 15.3 Maple 623 11050 2016 4230 1795 125 58 6.8 2.9 5.5 2.78 (8) #270 E

Spruce 414 14100 913 5820 1490 186 69 14.1 3.6 15.4 Maple 583 12800 1900 4720 1780 136 62 8.1 3.1 6.7 2.30 (9) #271 F Spruce 490 14650 1140 5570 1500 166 64 11.4 3.0 12.9 Maple 667 15500 2190 4790 1825 110 A 9 7.1 2.7 7.1 1.82 (10)

Formulas for calculating properties from vi- Vibrational damping at the frequency of the bration measurments are: fundamental resonance is given in the table as the or = __£° reciprocal of damping, "Q". Values for both spruce and maple are higher than those pre 'H - fL viously reported as typical. 0.946pf 2 lt E L calculated as Young's Modulus, E, - p and the of sound in the velocity specimens, C, appear to fall within the normal range of val- c / = v e7p~ ues for both longitudinal and transverse di- R = c/p rections . In Young's addition, the ratio of Modulus in Radiation ratio, R, was found to the longitudinal be slightly direction to that in the trans- higher than normal for the longitudinal grain verse, or cross grain, direction, E IU, , was . maple samples. This may be due to the lower also calculated for each sample. — density of these samples. Results for the properties of each sample Figures 1 and 2 show graphs of recipro- are summarized in the tabulation. In this tab- cal of damping (horizontal axis) plotted a- ulation samples are listed by the number of the gainst Radiation Ratio, p , (vertical axis ) for violin in which the wood represented by the sam- c/ spruce and maple samples, respectively. Points ple was used. The pattern of the is instrument are numbered in the order in which samples are also listed along with the number. listed in the tabulation of data. In the plots of grain DISCUSSION the longitudinal samples the points represented by[®|are the values for Norway spruce and Wood tested in this work was imported European Norway maple taken from the Barducci/ Pasqualini spruce and maple purchased from Andreas Gleissner tables and charted by Schelleng. As we have pointed out, points representing the Samples were from a single shipment and rep- wood from the Gleissner shipment all show high- resent the variation within that shipment. er values of Q.

Density of the spruce ranged from 414 to 494 Relation of stiffness along the grain to kilograms per cubic meter. For the maple* range stiffness across the grain of wood in top and was from 563 to 667. In the case of the maple back plates of violins is extremely importantto this was slightly lower than the values of 590 the proper tuning of the plates and for that to 750 reported in the work of Daniel Haines . 3

CAS #40,

EUROPEANSPRUCE GLEISSNER ACOUSTICALPARAMETERS

VELOCITY RECIPROCAL RADIATION Ell,-. SAMPLE DENSITY MODULUS OF SOUND DAMPING RATIO /F C Guam.D

Guam.

Guarn.B

Guam.C

Guarn.F

Strad.A

Strad.

Strad. C

Strad.

Q Stiffness,

Q, 30 NL #40, Nov. 1983 was found reason close attention was given to the values It that the relative distances between these connected of the ratio In the spruce which we points rather closely ap- Ej|/g| . proximate the tested this ratio~*varied from 11:1 to 22:1, spruce-to-maple ratios of the values. while in the maple variation was from 3.8:1 to Ell /e1 7.9:1. Considerable time was spent examining FUTURE WORK these ratios as they related the spruce to the maple in the plates of each instrument. It was Wood being a natural material subject to wide found that a second ratio of Ey for the /gi variations, it is difficult to draw firm con- spruce of the top plate to of the maple E||/eJ_ clusions from a few tests. For that reason of the back a number which we plate gave appears intend to keep up the testing, as much as time to be representative of the degree of differ- permits, of any wood which appears to be of in- ence of the woods of these two plates. terest for making instruments of the violin family. Figures 3 and 4 show graphs on which Ell (horizontal axis) against El (vertical axis) Regarding the measurements reported here, we are plotted for each of the woods which were shall follow the construction of the instruments measured. Dashed lines connect the points for being made from these woods and report at a lat- the spruce and maple used in each instrument. er date on how our results relate to problems en- countered in the tuning of the plates. EUROPrAM SPPUCE REFERENCES

1 I.Barducci and G.Pasqualini, II Nuovo Cimento _5 (5) 416-466 (1948). English translation in Musical Acoustics Part I,Ed. Carleen Hutchins,Dowden,Hutchinson & Ross, Inc. (1975) pp. 410-423.

3 J.C. Schelleng, J .Acous. Soc .America 35 (3) 326-338(1963).

3 D.W.Haines, Catgut Acous.Soc.Newsletter N0.31, May 1979. 4 M.A.Hutchins, Catgut Acous. Soc.Newsletter N0.36, Nov. 1981, pp. 29-31.

EUROPEAN MAPLE. ' fit* U q fl I I I I I l i -i-'*..--] MfcGA PAfftAi.l ♦ — Figure 3 t K-5f Sample Eh/EL spß*>ts No, to J —' x ,w * * * SPRUCE h I.ON6ITWOINAI, CPAitf - , - *j A 7 » *f /*, /.n At \ 'N. t *s, * 7®' C*©*S «RA|A/ I / \ 6' ID *©* 3' / ', » 9 a El *»

-^1= ■ i. i* I t.L i J i i i i i lz to to —no yso iso llr— — a Oh MtCA PASCALS Figure 2 ** —* Figure 4

CAS

v. Farewell—l've stopped him once forall, found in STRINGS: THE FIDDLER'S MAGAZINE He's met his destinie ; August 1894 I knew his time would not be long, And now no more scrapes he. So rantingly, so wantonly, So damnably scraped he ; He scraped till madness seized my soul, Zbe jft&Mer's (3bost: But now no more scrapes he ! (Sn Sfloriß tn Jilmc jFjQtteg.) VI. Not a sigh was heard, nor a BY sorrowful word, THE LAUREATE-ELECT. As his corpse to the garden I hurried, {WITH APOLOGIES MANY DEAD AND OTHERWISE.) And strange to relate, though I carried a corpse, I didn't feel anywayflurried ! I. I buried him darkly at dead ofnight, CRAPE, scrape, scrape, The sods with my shovel turning, On thy wretched fiddle, O beast ! There wasn't a moon so it couldn't give light, How I wish that my fist could reach thee, And the lantern —wasn't a-burning. My eyes on thy corpse should feast. Quickly and gladly I laid him down, O well for the fortunate man, And his fiddle I broke up for firewood. That he lives on a far shore, Who'd venture to say that he'd fiddle again ? Where the horror of hearing thy scraping Why certainly none but a liar would ! Never fosters a thirst for thy I

And the days and the weeks roll by, VII. And his fiddle keepson like a mill ; They told me gently he was dead, But oh ! if I had but a knife m a gun I wept but not with sorrow ; I'd jolly soon make him lie still ! But mybit —of conscience softly said Scrape, scrape, scrape, "Hill scrape again to-morrow /"— He'll never be quiel, I see ! And the grace and the peace of a day that is dead VIII. Will never come back to me. Fill high the bowl with gingerwine At one-and-three—why cherish sorrow? n. The deed is done, the fiddler's dead, fiddler 1 oh, scraper I His book of scraping toil is read, If you die a sudden death you'll only have yourselfto blame, His fiddle's burnt from tail to head j Oh, scraper I oh, fiddler ! Hurrah ! But still my conscience said How d'ye fancy " murdered" for your gravestone name ? " Old—boy—he'll scrape again to-morrow— t "

ill EI The scraper still went scraping on; Ah, distinctly I remember ; it was in the bleak December And through a chink my eyes of flame When I drank that wine at one-and-three—oh, how the fire did roar ! Gazed on him. In that hour, alone, And I sat and cracked the walnuts, with my back towards the door, I swore I'd stop his little game ! And my feet upon the and I chuckled more and more— For could I dance upon his grave, " He shallfiddle—Nevermore I" scraping His could not make me rave. And I sat, and still sat thinking, wine at one-and-three still drinking, And my Fill high the bowl with "shilling grape ! eyelids gently blinking as I poured out one glass more " But I My garden lies beneath the shade; turned with horror gaping, as I heard that fatal scraping, Ft that No more this howlingfiend shall scrape fiddler satand jabbered,as hefiddled near door— I'll buy a gun I have a spade. "Iwill leave thee—Nevermore I" Why my—eye Fiddler ! shrieked should the tear-drop lave ? " " I, ".thing of evil—scraper still, if man or devil I fit shoot him then dig his graveI "By the clatter howling round me—byAhe deed we both deplore, "Tell me, in that distant haven, on that oft-sung silent shore, " Shall I find a quiet corner where the scraper scrapes no more? IV. Quoth the scraper "Nevermore/"" So the stock ofmy gun to my shoulder I shaped, — And the for business shaping, in my easy chair is scraping, And I looked in the face of the fiend he as scraped j In my easy chair of leather, where he's often scraped before I tookaim, pulled the trigger—away flew the pill, And his eyes haveall the seeming ofa scraper's wildly dreaming, And his heart but once beat, and for ever grew still I And the sulphurround him gleaming casts his shadow on the floor— When's he going?—Nevermore./

(The end— o/ thePoem, not ofthe Scraper.)

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TO POETS,

away

gore

Oh,

fender,

;

first,

fiend, ;