From the very beginning, a bell possesses a specific note, whose harmonic tones must however be refined. Tuning a bell is a delicate operation that can only be done once, as a note can be lowered by removing metal but no material can be added to raise it. It is the foundry's tuner who decides where and to what extent metal should be removed, via internal grinding, until the right sound is obtained. Bells are tuned to the first five harmonics: the less the bell is touched after casting, the better the sound.