Micro-CT for Violins and other Stringed Instruments
A New Approach for Analyzing Instruments of the Violin Family
What about Stradivarius violins produces the rich, resonant sound associated with these 300-year-old instruments? Violin-making has changed very little since that time, but today micro-CT offers modern violin producers and acoustic scientists a unique tool for nondestructively evaluating an instrument’s structure, as well as a guide for the replication of original masterpieces. Micro-CT is also important in the valuation, insurance, and identification of valued instruments.
New approaches to studying violins, new and old
Since the 1990s, several researchers have collaborated in using micro-CT to study stringed instruments, including violins. The technology has provided images of instruments by Amati, Stradivari, Stainer, Guarneri ‘del Gesù,’ and Guadagnini to reveal the makers’ secrets. The major strength that micro-CT brings to the study of old violins, some valued at over $1 million, is its non-invasive, nondestructive methodology. The instrument being studied is only out of its case for a short time, during which an enormous amount of information is gathered. For newer instruments, micro-CT is used to resolve insurance disputes and for insurance identification. Perhaps even more important is the use of micro-CT in replacing antique parts with modern equivalents of identical measurements. And, micro-CT is informing modern violin-makers about density of wood, thickness, and internal measurements that ultimately affect the sound and quality musicians are seeking.
In the January 2018 issue of The Strad, a news magazine for stringed instrument musicians, connoisseurs, and producers, Rudolf Hopfner discusses benefits of micro-CT in evaluating stringed instruments. He clarifies the differences in the attenuation factors of wood, glue, and metal, and how this affects the preparation for scanning and the interpretation of the scanned results. For example, it’s recommended to remove metal parts, such as overwound strings or tailpieces with fine tuners, prior to scanning. Sometimes nails in original upper blocks or some specific glues can create special issues. Researchers need to make adjustments in their scans to obtain the best information.
A key advantage of micro-CT data, once the scans are complete, is that the data is readily available, all areas of the instrument can be visualized, and it is possible to make direct comparisons of different violin-makers (luthiers). Using Bruker’s SkyScan 2214, which covers the widest range of object sizes
and spatial resolutions in one single instrument, we have unique opportunities for 3D imaging and exact modeling of violins.
The SkyScan 2214 allows scanning and 3D non-destructive reconstruction of internal microstructure of objects as large as >300mm in diameter as well submicron resolution for small samples (Figure 2). This means that the entire violin can be scanned at one time. The world’s fastest hierarchical 3D reconstruction software speeds-up imaging object’s internal microstructure 10-100 times compared to traditionally used algorithms or GPU-accelerated reconstruction.
We hope you found this Image of the Month informative. If you have an Image of the Month sample that you would like us to scan, please contact us by calling Seth Hogg at 610-366-7103 or e-mailing email@example.com
Our thanks to Bruker for these images.
For more information on Bruker SkyScan Micro-CT Instruments:
Product Manager – Bruker MicroCTs
Micro Photonics Inc.
1550 Pond Rd. Suite 110
Allentown, PA 18104
P: 610-366-7103 ext 115