ANSI - American National Standards Institute
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Secrets of Stradivarius Violins Uncovered with the Help of Standards

New York, Jul 10, 2008

For centuries, musicians around the globe have agreed that violins crafted by Antonio Stradivari and his contemporaries produce the highest quality music in the world. These 17th and 18th century instruments, referred to as Cremonese violins, have a rich and full tone that no instrument maker has been able to recreate. Recent research, performed with the help of standards for CT scans, has revealed a possible explanation for the unique tone of these violins.

Researchers used computed tomography, commonly known as CT scans, to measure the density of the wood in both Cremonese and modern violins. The violins were scanned at Mount Sinai Hospital in New York City, using a multi-detector row CT scanner manufactured by Siemens, a company member of the American National Standards Institute (ANSI).

According to a research article released by the Public Library of Science ONE, the 3D image results produced from the scan reveal that Cremonese violins are created from wood that is unusually uniform and highly dense. The modern violins, conversely, were made from wood that was uneven in density.

On the basis of this research, some scientists theorize that the wood for the Cremonese violins was grown and harvested during a period where, due to climate conditions, trees grew more slowly and more uniformly throughout the year. The wood used to create modern violins, which were grown in a different climate, showed uneven density representing faster, less dense growth during warm seasons, and slower growth in colder weather. Researchers posture that this uneven density does not provide the rich, full sound that Cremonese violins produce.

CT scanning equipment, typically used for medical purposes and critical to this experiment, is developed, manufactured, and tested with the help of standards.

ASTM E1570-00(2005)e1, Standard Practice for Computed Tomographic (CT) Examination, describes procedures for performing CT examinations which disclose physical features or anomalies within a given test object. Developed by ASTM International, an ANSI member and accredited standards developer, this standard addresses the general use of CT technology, facilitating its use for a diverse range of applications from medical imaging to object diagnostics.

An international standard developed by the International Electrotechnical Commission (IEC) provides guidelines for testing CT scanners to ensure that the images produced are accurate. IEC 61223-2-6 Ed. 2.0 b:2006, Evaluation and routine testing in medical imaging departments ­ Part 2­6: Constancy tests ­- Imaging performance of computed tomography X-ray equipment, standardizes the components of scanning objects and people that can effect the image, including positioning of objects.

This standard was developed by IEC Technical Committee (TC) 62B, Diagnostic Imaging Equipment. The USNC-approved Technical Advisory Group (TAG) Administrator for this TC is the Medical Imaging & Technology Alliance (MITA). MITA is a division of the National Electrical Manufacturers Association (NEMA), an ANSI member and accredited standards developer.

The guidelines and specifications outlined in standards like these have helped to solve the mystery of Stradivari violins. Listeners worldwide can finally sit back and enjoy the music!

Graphic demonstrating violin density

ISO TC 229 Nano technology Wiki