Page 78 - The Strad (February 2020)

MAKING MATTERS
Points of interest to violin and bow makers

The sound of science

Tom Croen reports on a 2019 experiment to discover how much variation in sound can be gained
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he space between what we know
T ngerboards varied, even when made to
the same dimensions, and that swapping
and what we think we know is
a treacherous place. When we
the ngerboard on an instrument altered
make choices as violin makers,
we usually build on past experience to the sound in unpredictable ways. I had
measured the wood properties of more
guide us, but we are sometimes than 500 ebony violin and viola
confounded by unexpected outcomes. ngerboards, and felt I had begun to
At the 2019 Oberlin Acoustics understand how di—erent ngerboards
Workshop I participated in a project could in’uence the sound.
designed to learn more about how the “e Journal of the Catgut Acoustical
neck and ngerboard assembly in’uence
-2+'8#3!8&9 1!&' #@ 323>33& l£'đm !2& 3( '#32@ Society (November 2000) contains a
an instrument’s sound. “e workshop had non-invasive diagnostic method for
a brilliant team making precise analytical Joseph Grubaugh from California and tuning ngerboards, by Bill Atwood
measurements with very sensitive Mark Benischek from Illinois. and Brian Keeney, based on subjective
equipment. We sampled ngerboards listening to the instrument. If one applies
made from both ebony and alternative THE EXPERIMENT modelling clay in increasing amounts
materials in the hope of discovering Like the cooking shows on TV we had under the wide end of the ngerboard,
something meaningful. limited time, as well as a skeleton B0 drops in frequency. By playing and
Joseph Curtin helped us both to design workshop. So we designed an experiment listening with each additional application
the project with the analytical team and that we hoped would show analytically of weight, changes can be heard making
to summarise our ndings so we could what was happening when we modied it easy to decide when the instrument
present it to the workshop. “ere was the vibrating frequency of the sounds best. “en the adjustments are
also Boris Haug from Switzerland, ngerboards, which in turn changed a nished by strategically removing wood
where Sonowood ngerboards are made. primary mode of vibration of the body from the ngerboard. “is empirical
“ey are addressing the scarcity of ebony (often called ‘B0’, or B-Zero). approach of comparing the sound of an
by designing attractive alternatives that we I had noticed earlier in my career that instrument, along with tracking changes
can use today. Also participating were the weights and tap tones of ebony in B0, presents a useful strategy for

Fingerboard Colour in FRF Weight (grams) !&-!ধ32 8!ধ3 A0 (Hz) B0 (Hz) B-1 (Hz)
Croen 2019
Ebony #1 Black 66.1 3.82 278 251 166
Ebony #2 Red 65.3 4.44 281 275 170
Sonowood Scots pine Blue 64.4 5.31 281 293 171
Haug 2019
Sonowood maple Black 69.6 4.61 263 322 179
Ebony Red 58.6 4.55 268 284 171
Sonowood spruce Blue 65.4 4.94 265 318 176
Benischek 2018
Ebony Red 65.3 4.43 278 276 178
Sonowood blacknut Black 71.6 4.58 275 296 183
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76 THE STRAD
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