With this issue, we begin a new feature, "Recent Papers for Makers." For years, the Journal has listed papers in musical acoustics published in journals or presented in conferences around the world. We will now also review the many journals and newsletters addressed to makers and list papers that should be of interest to technically-minded makers. To help us be complete, we ask members to inform the office when they know of papers we should list.
I encourage you to read the announcement for ISMA '98: Tone and Technology in Musical Acoustics to be held near Seattle, Washington June 26 - July 1, 1998. Planning is underway, and the organizing committee would appreciate hearing from persons who want to participate or attend. The ISMA '98 home page at http://www.boystown.org/isma98 will provide up-to-date information.
As always, we appreciate your feedback about the Journal so that it can be improved and better meet the members' needs.
Good reading!
A. Thomas King
The Violin Octet celebrated its fortieth anniversary in 1997, measured from its conception in 1957 when composer Henry Brant asked for an ensemble of consistent-sounding instruments spanning the range between the double bass and something well above the standard violin. This paper reviews the history and challenges of designing and constructing the Octet.
10 - Sound Distribution from Forced Vibration Modes of a Violin Measured by Reciprocity and TV Holography by Henrik O. Saldner, N.-E. Molin, and Erik V. Jansson
How do certain vibration modes couple to the radiated sound field? The spatial sound radiation of forced vibration modes of a violin is measured using a mechanical-acoustical reciprocity technique. The violin is set into vibration by a small loudspeaker placed in front of the violin. The vibration pattern is monitored by TV holography, and the vibration velocity amplitude at one foot of the bridge for the top plate is measured using TV holography and an accelerometer. Reciprocity predicts that this velocity is proportional to the sound pressure we would measure with a microphone at the speaker position if a sinusoidal force from the string were acting at the bridge. For a forced vibration mode at a low frequency, at 534 Hz, in the "main wood" frequency range, the sound radiation was found to be close to spherical, also verified with measurements in an anechoic chamber. Acoustical "short-circuiting" is likely to reduce the multipole radiation and thus enhance the monopole radiation of this complex, the forced mode (not a simple breathing mode). At 2548 Hz, however, the sound radiation was found to be quite sensitive to direction. Measurements made in the optical laboratory with no extra acoustical treatment are in fair agreement with those performed in the anechoic laboratory.
17 - Another Look at the Swiss Cheese Violin by Oliver Rodgers
Harmonic analyses were made of the glissando sounds of the Swiss Cheese violin, Hutchins SUS 185, when the holes in the ribs were opened in eight different patterns. Rough descriptions of the nodal lines of the vibrating patterns of the first few modes of vibration which produce appreciable sound were also acquired in a separate experiment. The enormous changes in the tonal characteristics as the holes are opened up are clearly described. The most striking feature is an increase in frequency of the first air mode as greater numbers of holes are opened. Holes in the different locations have different effects on the frequency of the first air mode. The results provide some insights into the complex interactions in the violin between air and mechanical modes of vibration and raise some questions for further study.
24 - Strings and Metallurgy by Norman C. Pickering
Windings of metal wire are applied to low-pitch musical strings to increase tension at a desired pitch. Metals are selected for density, but often present difficulties in respect to ductility, corrosion resistance, and appearance. Production of high-quality strings requires close attention to alloy selection, heat treatment, and mechanical working of the many different metals used.
30 - Finite-element Analyses of "Stradivari" and "Modern" Top Plates by A. D. Lindsay and R. A. Willgoss
Although luthiers agree that differences in arch heights and plate contours have significant effects on construction and the performance of the assembled violin, there is little systematic investigation of how arching affects plates. A luthier's practical experience will suggest some of the sensitivities; however, it is impossible to construct numerous plates, all identical except for a carefully controlled difference in arching, and to evaluate the differences. If nothing else, each piece of wood is different. Finite element analysis of violin plates provides a way to undertake the needed systematic investigation. It is possible to "construct" as many identical plates as desired, vary any available parameter, and investigate the effects on numerous plate vibrational characteristics. This study finds that the modes of a "Stradivari" violin top plate are relatively unaffected by most parameter changes, whilst a "modern" violin shows some significant movements of modes. This may explain the relative merit of Stradivari instruments in that the arching and contours may require less accurate tuning of modes than do the arching and contours of some modern violins to obtain the same desired resonance.
This paper is based upon a collection of bridges accumulated by a concert violinist over his career. The bridges were cut by many prominent U.S. makers, including those at the Wurlitzer Violin Shop in the 1950s. The paper presents dimensional and acoustical data for these bridges and gives details for a high frequency "mini-shaker table" used in this study. The paper discusses how this device can be used to guide the carving of new bridges.
44 - Down-home Lutherie II: a Computer-based Technique for Measuring Integral Loudness and Observation of a Bow-velocity Independent Loudness Quantity by Carolyn W. Field and Frank H. Field
The authors describe an improved apparatus and technique for measuring loudness. Compared with a technique described in their previous paper (Field and Field 1997), (1) the measurements are much faster and require only one person; (2) the subjectiveness of the measurements is much reduced; (3) a specialized reproducible method of hand bowing is developed; and (4) the precision of the loudness measurements is increased to 5% relative standard deviation for replicate measurements. The authors also describe a curious quantity related to loudness, the Voltage Sum, which is sensibly independent of bow velocity.
52 - Tuning the A0 Mode Without Changing the Body or f-hole Size by By J. L. Miles
The paper describes a procedure for adjusting the A0 mode of an instrument without altering the instrument's exterior appearance or the size. This procedure, together with the procedure described in a previous paper for adjusting the A1 mode, allows the maker to achieve the optimal tonal relationships.
60 - Great Guitars by R. Shaw