Audio & Acoustics

News NY Times: String Theory - New Approaches to Instrument Design MSNBC Website: How to Build a Masterpiece View an audio slide on: Newsobserver	Musical instruments generate wonderful, inspiring sounds through their vibrations. Polytec vibrometers can help us understand how this happens with early work already done on violins, cembalos and dulcimers. Vibrometers are also indispensable tools for loudspeaker design identifying diaphragm resonances that are deleterious to the sound quality. Vibrometer measurements provide an experimental basis for sophisticated acoustic investigations like structural-acoustic response (sound field) predictions, acoustic imaging and anti-sound research. Acoustics are also increasingly important in product design. The focus is on how and where are undesired noises generated and at which point or location can countermeasures be taken.
Applications 3-D Motion in Stradivari and Guarneri dG Violins How to See Brake Sounds Basic Mechanism of Hearing Noise Measurement in Micro Drive Systems	Products PSV-400 Scanning Vibrometer PSV-400-3D Scanning Vibrometer OFV-5000 Modular Vibrometer PDV-100 Portable Digital Vibrometer	Links East Carolina University: Bissinger Examines Famed Violins   University of Tuebingen: Inner Ear Research Head Acoustics: Binaural Transfer Path Analysis

The Secrets of Stradivarius and Guarneri Violin Masterpieces

This was a once-in-a-lifetime opportunity to test a Guarneri del Gesu and two Stradivarius masterpieces. Scans of various portions of each violin were stitched to provide a true 3-dimensional visualization. 3-D data also permits volume changes to be computed related to air forced through the f-holes, previously shown to be a new radiation mechanism a major contribution to the sound near 500 Hz. Another indirect radiation mechanism – A1 cavity-mode-forced body motion – was seen quite strongly in one Stradivarius and one Guarneri del Gesu. Research continues in an effort to combine the Polytec vibrational data with measured acoustical and density/shape data in order to develop a vibro-acoustic solid model. Some of the secrets that make these violins masterpieces might be revealed from this model and allow modern violin making to approach the level these masterpieces achieved hundreds of years ago.

For more informations please Contact Dr. George Bissinger Professor of Physics East Carolina University phone:(252) 328-1860 e-mail: bissingerg@ecu.edu