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.
Royal National College, College Road, Hereford, HR1 1EB, United Kingdom.
Brian
B
Capleton
D016880:Anisotropy; D006801:Humans; D009146:Music; D010897:Pitch Discrimination; D011571:Psychoacoustics; D013018:Sound Spectrography