A Database of Measured Musical Instrument Body Radiation Impulse Responses, and Computer Applications for Exploring and Utilizing the Measured Filter Functions

Directional impulse responses were collected for six stringed instruments, including two classical acoustic guitars, an archtop jazz acoustic/electric guitar, a mandolin, a violin, and a Hardanger (Norwegian folk) fiddle. Impulse responses were recorded simultaneously from 12 microphones spaced uniformly at the vertices of an icosahedron. Data was collected for all instruments with a human player holding the instrument, and for some instruments also with the instrument suspended without being held by the player. For one guitar, the violin, and the mandolin, the position was adjusted by small angles, and a total of 72 impulse responses (six sets of 12 microphones) were collected. Various signal processing techniques were used to investigate, factor, store, and implement the collected impulse responses. A software workbench was created which allows virtual microphones to be placed around a virtual instrument, and then allows signals to be processed through the resulting derived transfer functions. Signal sources for the application include plucked and bowed string physical synthesis models, or any external sound source. Instrument body transfer characteristics can be parametrically edited, adjusting body size, main resonances, etc. Applications of the database and application software have included adding directional radiation models to physical models for virtual reality and composition, and adding more realistic body resonances to electronic stringed instruments for real-time performance.