Posted on July 31, 2019May 23, 2025 by S Mc Herr Helmholtz’ Tube Herr Helmholtz’ Tube by Mike Doolin previously published in American Lutherie #91, 2007 See also, “There’s a Hole in the Bucket” by Cyndy Burton “Sideways” by John Monteleone “Three Holes are Better than One” by Robert Ruck Design innovator Mike Doolin tried an interesting experiment. Mike’s guitars have the distinctive double-cutaway feature and they don’t lend themselves to a port up in the neck/cutaway region for reasons of underlying structure. So Mike put one in the lower bout and very unexpectedly found his Helmholtz resonance had raised something like a major third. He felt that compromised the responses of the guitar. His solution was to “tube it.” The side was ported before I assembled the guitar. After gluing the back on, I realized the change in the Helmholtz when I tapped on the guitar with the port open. It seemed obvious that a shift of a major third up was going to radically change the sound of the guitar, probably killing most of the bass response. I knew that ports in bass reflex speakers are often tubes, where the longer the tube the lower the resonant frequency. I also knew that the tube could be either inside or outside the box. So I initially held a roll of toilet paper against the port, letting the cardboard core of the roll form a tube that extended the port. That dropped the main air resonance back down, showing me that I was on the right track. Then I turned a tube of wood on my lathe to fit the hole and experimented with the length until the air resonance moved less than a half-step with the port closed or open. I recall the port being 1 1/4" in diameter and the tube being about 2 1/4" long, but that’s just from memory. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on June 26, 2019May 23, 2025 by Dale Phillips The Colombian Andean Bandola The Colombian Andean Bandola by Luis Alberto Paredes Rodríguez and Manuel Bernal Martínez previously published in American Lutherie #96, 2008 The Colombian Andean bandola is a transcultural product similar to plectrum-played antecedents from Asia and Europe. It is a 12-string, 6-course soprano instrument with “flat” top and back, and is the solo melodic instrument in the Colombian Andean quartet, which consists of two bandolas, a tiple (see Big Red Book Volume Seven, previously published in AL#82), and a classical guitar. The name “bandola” comes from the old Persian-Arabic word pandura. Derived from the name of the European lute, the word refers to a great variety of instruments of medium and high register with melodic functions. The direct ancestor of the bandola is the guitar through the Spanish bandurria and the soprano guitars, and which after taking its form in Colombia during the 19th and 20th centuries, continues to undergo transformations in its morphology and usage. The Colombian Andean bandola has two developmental lineages: on one hand, the denomination line which makes reference to its name, and on the other, the construction line which makes reference to its morphological features (Bernal, 2003). The name of the bandola comes from the pandura (known since the 10th century) following the European lute, and one of its families known as the “mandoras family.” These 4- to 6-course instruments with thin bodies had a variety of pitches (a mixture of perfect fourths and fifths) and scale lengths ranging between 37CM and 42CM. By the year 1700, the mandolines emerged in Italy when the size of the mandola was reduced, prevailing and persisting in Italy in two different models: the Milanese mandoline with a thin, slightly arched body, and six courses of either gut or metal strings tuned in perfect fourths; and the Neapolitan mandolin with a bowl back body, a cranked (bent) soundboard just where the bridge is placed, four courses of metal strings tuned like a violin, and strings fastened to the end of the body by way of a tailpiece. The scale for both models is about 32CM to 34CM. In the 18th century, mandolins began to be manufactured with flat or slightly arched sides and back, especially in France, Germany, and Portugal. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on January 13, 2010May 27, 2025 by Dale Phillips Letter: Circles in Classical Violin Design Letter: Circles in Classical Violin Design by Jim Blilie Originally published in American Lutherie #89, 2007 Hi Tim, I’m sure Michael Darnton has infinitely more experience with violin design and a much more sensitive eye for the form of violins than I do (See The Power of Circles). That being said, I was really bothered by his article. Mr. Darnton writes that his theory of circles in the design of classic Cremonese violins seems to be the only one that will produce aesthetically pleasing shapes. I have no doubt that circles were used extensively in the design of violins, since they are much easier to draw than parabolic, hyperbolic, or elliptical curves. But he goes on to say that essentially all the extant violins of the height of the Cremonese school do not follow his plan. He posits various reasons for this, but in engineering, if the data don’t match your theory, you go back to the drawing board and find a new theory! Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on January 11, 2010May 27, 2025 by Dale Phillips Review: Acoustics of Wood by Voichita Buchur Review: Acoustics of Wood by Voichita Buchur reviewed by Nicholas Von Robison Originally published in American Lutherie #57, 1999 and Big Red Book of American Lutherie Volume Five, 2008 Acoustics of Wood Voichita Buchur CRC Press, 1995 ISBN 0849348013 Voichita Buchur’s book Acoustics of Wood is a synthesis of over fifty years of work by the scientific community into the physics of how this complex material responds to vibrational wave stimuli. With almost 800 references into the literature and about ten years from inception to its being published in 1995, it is a tremendous resource for the luthier’s understanding of his/her main material. I don’t get the feel from the text that the author is a maker herself, even though she is a member of the Catgut Acoustical Society. The book is heavily weighted towards violin family instruments, but this doesn’t make the book any less valuable to guitar makers. After a short, well written, general discussion on the anatomical structure of wood (macro, micro, and molecular), a brief outline is presented dividing the book into three major sections. Part One explores the physical phenomena associated with the effects of acoustic waves in forests (windbreaks to attenuate noise) and architectural acoustics (concert halls, office buildings, restaurants) with wood being used as a construction material and insulator in conjunction with other nonwood materials. A survey of six European concert halls and their geometrical, acoustical, and construction data is pretty interesting. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on January 11, 2010May 28, 2025 by Dale Phillips Review: Research Papers in Violin Acoustics 1975–1993 Review: Research Papers in Violin Acoustics, 1975-1993 edited by Carleen Hutchins and Virginia Benade Reviewed by David Hurd Originally published in American Lutherie #59, 1999 and Big Red Book of American Lutherie Volume Five, 2008 Research Papers in Violin Acoustics 1975–1993 Carleen Maley Hutchins, Editor Virginia Benade, Associate Editor Acoustical Society of America, ISBN 1563966093 It is with some trepidation that I pen this, my first book review for American Lutherie. As I noted to Tim Olsen, “But I’ve never made or even played a violin. How can I review such books and do them justice?” “Well,” he replied, “most of our readers are in the same position. And, having written the review, you can keep the books.” So began several months of fascinated reading of this two-volume set of violin research papers. A little over half of the papers in this collection are from the Journal of the Catgut Acoustical Society, Series 1 or 2 and the Society Newsletter. Both the Society and the journal are still alive, well, and active in mostly violin family instrument research. The remainder of the articles come from such technical journals as: Journal of the Acoustical Society of America, Acustica, Journal of the Acoustical Society of Japan, Journal of Audio Engineering, Journal of the Violin Society of America, Scientific American, Wood Science and Technology, Acoustics Australia, Acta Metallica, Music Perception, American Journal of Physics, Interdisciplinary Science Review, Strad, and Physics Today. Papers from the proceedings of several conferences on acoustics and modal analysis are also represented. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
