Mapping the vibroacoustic behavior of harp soundboxes

• Published in: The Journal of the Acoustical Society of America 2009-04, Vol.125 (4_Supplement), p.2515-2515
• Main Authors: Daltrop, Shira, Kotlicki, Andrzej, Waltham, Chris
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4783448

Modern harp soundboxes typically consist of a thin soundboard made of an acoustic wood with a definite set of resonances, and a relatively heavy conical or polygonal back in which there are several holes. These holes exist to allow access to the string attachments but also have important acoustical properties. Harps more than 200 years old frequently have small holes in the soundboard itself, and none in the back. The quality of the sound radiation from a harp is determined in large measure by the vibrational behavior of the soundboard and the motion of air in the soundholes. Using an impact hammer, accelerometer and acoustic-velocity probe, we have mapped the velocity of a harp soundboard, and that of the air in the soundholes, in response to excitation at the string attachment points. The relationship between these motions is complex but also crucial in determining the quality of the instrument.