Measurement of decay curves of individual partials of singly excited piano and harpsichord strings
Eric B. Arnold · The Journal of the Acoustical Society of America · 1979
Curves of relative sound-pressure level versus time for low-order partials (typically up to the fourth) of single piano strings have been obtained. A wide dynamic range contributes to the recognition of a number of characteristic forms which can be related to physical attributes of the piano. These forms appear to be essentially equivalent to forms obtained for the relative energy transmission to the bridge by a two-string system [G. Weinreich, J. Acoust. Soc. Am. 62, 1479 (1977)]. Beats between the two polarizations of each partial are frequently observed, but occur much less often on good pianos in good condition than on other instruments. This suggests the use of these measurements as an indicator of piano quality. Measurements on harpsichords show that beating of the upper partials is the rule rather than the exception [cf. R. W. Pyle, Jr. and T. J. Schultz. J. Acoust. Soc. Am. 39, 1220(A) (1966)], raising the question of what it means to tune these instruments, particularly when the subtleties of different temperaments are involved. Work is in progress to make quantitative comparison with theoretical curves. [Work supported by NSF.]