A large bourdon church bell being tuned in the foundry… a bell is unlike a pure tone instrument that is naturally in tune with itself; a church bell has several harmonics, called partials, or overtones, that each must be tuned along with the prime note according to a musical standard.
The tuning of a bell is both an art and a science accomplished by first notating where each of the partials are found, then shaving metal from the inside of the church bell thus lowering the note.
The bell can never be tuned up, it must be tuned down to the note as the act of shaving the metal from the inside of the church bell increases its volume thereby lowering the note of the bell.
While this is important for all church bells in order to have what may be described as “ringing true”; it is less important for a single church bell as it is for multiple church bells that will sing together and make music… the choir must all sing in tune for the music to be beautiful!
For more information about the tuning of church bells, visit our post on The Importance of Tuning.