Beats of a String of Piano (2nd Report)
Takesi Yanagisawa, Kijuro Nakamura · Journal of the Japan Society of Precision Engineering · 1967
In the beats of one string of piano the true beats can not be explained by the inharmonicity of one dimensional vibration. The authors' observation shows that one string vibrates in two principal axes. The true beats are caused by the interference between these same order harmonics. Two dimensional motions of one string are attributed to the directionality of the bearing and that of the geometrical moment of inertia of the string.