FRIDAY MORNING, 20 MAY 2005 REGENCY E, 8:30 A.M. TO 12:00 ...

FRIDAY MORNING, 20 MAY 2005
BALMORAL, 8:15 A.M. TO 12:00 NOON
Session 5aMU
Musical Acoustics: String Instrument Design and Construction
Thomas D. Rossing, Cochair
Physics Dept., Northern Illinois Univ., De Kalb, IL 60115
Christopher E. Waltham, Cochair
Dept. of Physics and Astronomy, Univ. of British Columbia, 6224 Agricultural Rd., Vancouver, BC V6T 1Z1, Canada
Invited Papers
8:15
5aMU1. Acoustical considerations in the design—and re-design—of the violin. Joseph Curtin Joseph Curtin Studios, 3493 W.
Delhi, Ann Arbor, MI 48103, violins@josephcurtinstudios.com
The violin is a highly evolved instrument which has long resisted significant changes to its design and construction. Still,
acoustical research over the past several decades has shed sufficient light on the workings of the violin that makers can now consider
non-traditional approaches to their craft in order to optimize the sound, playability, and consistency of their instruments. The work of
researchers such as Duennwald, Haines, Hutchins, and Weinreich will be considered in terms of its usefulness as a guide to building
better violins.
8:40
5aMU2. The violin octet and bowed string instrument design. George Bissinger Phys. Dept., East Carolina Univ., Greenville,
NC 27858
Modal analyses were combined with room-averaged acoustic measurements of a complete octet to assess Schellengs fundamental
scaling design assumptions: similarity of shape and flat plate scaling. The scaling employed only the two lowest strongly radiating
violin resonances, the main air A0 and main wood comprised of the first corpus bending modes B1 and B1 . A0 fell below the
desired pitch placement (1.5 lowest string pitch, while the B1 complex generally straddled the desired placement at 2.25.
Difficulties in properly scaling A0 derived partly from an unreliable theory that failed to incorporate A0 coupling to A1 first
length-wise cavity mode, and partly from inability to incorporate cavity wall compliance. Wall compliance dropped A1 into main
wood region even though larger instruments were designed successively shorter; the A1/A0 frequency ratio rose from 1.5 to 2.0
smallest to largest. Modern models sensitive to cavity shape predict A0 and A1 within 10% over the octet, ranging over 4.5:1
in length, 10:1 in f -hole area, 3:1 in top plate thickness, and 128:1 in volume. A0 radiates strongly over the octet, while
surprisingly A1 is the dominant radiator in the main wood region for the large bass even though A1 was never included in the scaling.
9:05
5aMU3. The acoustics of hammered dulcimers. David R. Peterson Dept. of Mathematics, Univ. of Central Arkansas, Conway,
AR 72035, DavidP@uca.edu
The hammered dulcimer, a stringed instrument played with two wooden hammers, probably originated in the Middle East, but it
has become part of the musical culture of many countries. In the U. S., the folk revivial in the 1970’s sparked renewed interest in the
hammered dulcimer as a concert instrument. Today, despite some consolidation in the retail market, there are still hundreds of
builders, mostly amateurs, who experiment with the basic design. The most important design parameters will be discussed from a
practical and acoustical point of view: soundboard size, shape, and composition, internal bracing, bridge shape, string arrangement and
composition, hardness of bridge caps, hammer weight and stiffness, instrument resonances due to the unique string splitting and
stiffness of the body, and soundboard modes.
9:30
5aMU4. Classical guitar construction: The acoustician’s tale. Bernard E. Richardson School of Phys. and Astron., Cardiff Univ.,
5 The Parade, Cardiff CF24 3YB, UK, RichardsonBE@cardiff.ac.uk
The vast majority of guitars produced today are built according to general principles laid down in the nineteenth century.
Nevertheless, the devil is in the detail, and innovative makers constantly reappraise the design and construction of instruments in their
endeavors to control quality or to seek ‘‘improvement.’’ The maker’s approach, necessarily, tends to be pragmatic, but it is one which
can be greatly informed by the application of relatively simple acoustical models. This paper will examine various important design
aspects—for example choice of materials, body size, strutting, soundboard thickness—introducing the basis for making informed
decisions.
5a FRI. AM
2589 J. Acoust. Soc. Am., Vol. 117, No. 4, Pt. 2, April 2005 149th Meeting: Acoustical Society of America 2589