TITLE:
Partial Frequencies and Chladni’s Law in Church Bells
AUTHORS:
William A. Hibbert, David B. Sharp, Shahram Taherzadeh, Robert Perrin
KEYWORDS:
Church Bell, Partial Frequencies, Chladni’s Law, Timbre, Virtual Pitch, Strike Pitch
JOURNAL NAME:
Open Journal of Acoustics,
Vol.4 No.2,
June
3,
2014
ABSTRACT: The rim partials of a
church bell (those with an antinode at the soundbow) generate the strike pitch
or perceived note of the bell. The spacing in frequency of the higher rim partials
has an important effect on the tonal quality of the bell. Investigations into
the partial frequencies of 2752 bells, both bronze and steel, of a wide variety
of dates, founders and sizes, show a simple and unexpected relationship between
the frequencies of the rim partials. This relationship explains why attempts to
tune the higher rim partials independently have failed. A modified version of
Chladni’s law provides insight into the musical relationship of the partials,
and predicts the partials of individual bells well, but fails to give a simple
model of the spacing between the partials seen in bells with different
profiles.