Tuning a bell is a process we approach with precision and the careful skill of our most experienced craftsmen.
After our bells are removed from the pit and shaken out of the mold, they go through our tuning process to bring each of the five most prominent partials in agreement with each other. Multiple partial tones are produced when a bell is struck. The five most prominent of which help to establish a bell’s overall timbre and are tuned to extremely close tolerances in order to ensure that each bell sounds according to client specifications.
Musically speaking, all pitches and frequencies regard the international standard of A=440Hz. Industry standards for tuning tolerances are +/- 4 cents for carillon tuned bells and +/- 12-25 cents for church bells that are to be used for other purposes than playing structured music.
Standard practice calls for casting a bell thicker than what is required in order to work with a tuning reserve along the interior of the bell. This additional metal initially raises the overall pitch of the bell and is the reason why bells do not sound very good when removed from the mold. An initial tonal analysis is taken from the bell in the ‘as cast’ state in order to establish a method for tuning.
Bells are then installed into lathes, both horizontal and vertical depending on size, in order to cut metal out of the interior of the bell to bring each partial tone in agreement with the other. This is a laborious and tedious task that takes great care in order to accomplish. This is also the moment when a bell’s sound is finalized and will be the sound that is produced over centuries of use. Once tuned, bells never should fall ‘out of tune’ with proper maintenance and care. The tuning process for bells could be compared to something like diamond cutting; only removing what is essential in order to bring out the sweet brilliance and clarity of the material. If too much metal is removed from a bell, the overall partials will become flat and hollow, rendering the bell unsuitable for use. The bell then must be broken up and tossed back into the furnace to be remade.