False beats in coupled piano string unisons.
The behavior of a unison pair of piano strings coupled by the soundboard bridge, when one string has localized anisotropy in the reactive part of the bridge admittance for a given partial frequency, can be investigated using a theoretical matrix description. The anisotropy can cause what in piano tuning terminology is referred to as "false beating" in a partial of the single string. A mathematical model can be used to illustrate how "mistunings" between the strings of the unison (measured when the strings are sounding in isolation from each other) may theoretically arise as a consequence of the normal practice in piano tuning, of eliminating or reducing audible beating in the unison when both strings are sounding. "False beats" in a single string partial can be "inherited" by a partial of the coupled unison's spectrum, and mistunings between the strings can eliminate or reduce the appearance of this inheritance.
Capleton
Brian
B
Royal National College, College Road, Hereford, HR1 1EB, United Kingdom.
D016880:Anisotropy; D006801:Humans; D009146:Music; D010897:Pitch Discrimination; D011571:Psychoacoustics; D013018:Sound Spectrography