CAS Journal
May 2002
Volume 4, No. 5 (Series II)

To Our Readers

This issue should represent a "watershed" of sorts for acoustical scientists and string enthusiasts who enjoy reading authoritative articles about string instrument acoustics, guitars,and violin making. The issue is dedicated to Erik V. Jansson. We congratulate him on his long, productive career in violin acoustics and related fields.

In order to celebrate Dr.Jansson's achievements, we gave honorary editor privileges to Anders Askenfelt and Johan Sundberg (present and past CAS Vice Presidents for Scandinavia). Askenfelt and Sundberg asked six "senior statesmen" of CAS to summarize the current state of knowledge and to offer their personal perspectives on physical modeling, optical studies,guitar acoustics, violin making, sound radiation, and violin modes. These invited articles make good reading because these authors graciously lay many important findings right at our feet. The articles include reviews of experimental and theoretical advances through the years, and exciting new findings based on empirical studies. These should be benchmark papers for years to come.

In addition, players should take interest in Knut Guettler's perceptive and inventive article on playing harmonics, also known as "flageolet tones." Finally, Mark French offers a clever analytical function for drawing instrument outlines.

Good reading!

Jeffrey S. Loen

Table of Contents with Abstracts

2 - Authors

3 - Passings

4 - Comments on a Paper Entitled "The Essential Musical Properties of Musical Instrument Wood" by Daniel W. Haines

From the Contributing Editors

5 - On Playing "Harmonics" ((Flageolet Tones) by Knut Guettler

Technical Note

8 - Instrument Body Description Using Polar Coordinates by Mark French

Special Feature - Erik V. Jansson - 60 Years

11 - Introduction by Anders Askenfelt and Johan Sundberg

12 - Numerical Simulations of Stringed Instruments — Today’s Situation and Trends for the Future by Antoine Chaigne

21 - Visualizing Instrument Vibrations and Sound Fields — The State of the Art by Nils-Erik Molin

A review is given of recent applications of modern optical techniques to visualize structural vibrations and sound fields in musical instruments. The advantage of optical techniques in this context is that they give an image of the measured quantity without disturbing the measurements. The techniques considered are usually referred to as TV holography (also called Digital or Electronic Speckle Pattern Interferometry, abbreviated ESPI or DSPI), phase modulated TV holography, pulsed TV holography (pulsed holographic interferometry) and scanning Laser Doppler Vibrometry (LDV).

30 - Simple Models as a Basis for Guitar Design by Bernard E. Richardson

37 - Sound Radiation from the Violin - As We Know It Today by Gabriel Weinreich

43 - Body Vibration of the Violin — What Can a Maker Expect to Control? by Jim Woodhouse

50 - Empirical Tools in Contemporary Violin Making: Part I. Analysis of Design, Materials, Varnish, and Normal Modes by Martin Schleske

The perfection of the violin by the famed old masters is attributed to a long history of passionate innovative empirical work that has been replaced in modern times by a devotion to traditional prototypes. Improvements in violin design and performance during the 17th and 18th Centuries can be correlated with the development of progressively more demanding playing styles by composers, including Monteverdi, Corelli, and Torelli. The successful empirical approach of the old masters can be applied today using careful measurements, recordings, and documentation that allow us to relate specific changes in design to specific change in sound.

Our work has documented the major aspects of instrument design (arching, thickness graduation pattern,a nd body outline shape) and modal characteristics of about 90 fine reference instruments, including many old Italians. We have also measured the materials in old Italian instruments, which generally are similar to modern materials. For example, the density of an entire top plate from a Stradivari cello is 0.39 g/cm3, which is not unusual. Further, our measurements indicate that the damping properties and modal characteristics of old and contemporary fine instruments are of comparable magnitude.

Tools available to the violin maker include selection of design, materials, varnish treatments, sound analysis, and modal analysis. Successive varnish layers can enhance or denigrate material quality. Making "tonal copies" using modal analysis at many steps of the working process allows the maker to change the geometry of the copy to compensate for material differences between the reference instrument and the copy.

Interesting Articles in Other Journals

62 -

In the Next Issue of CAS Journal

66 -

ISMA 2001

67 -

A Call for Papers

68 - A Special Issue of the Catgut Acoustical Society Journal - May, 2003

Acoustics of Early String Instruments

Meeting Announcements

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