Strike tone

The strike tone, strike note, or tap note, of a bell when struck is the dominant note perceived immediately by the human ear. It is also known as the prime or fundamental note. However, an analysis of the bell's frequency spectrum reveals that the fundamental only exists weakly and its dominance is a human perception of a note built up by the complex series of harmonics that are generated. The correct harmonic tuning of the bell is therefore important in creating a good strike tone.

When a bell is struck, the energy imparted causes vibration of the bell in a complex manner and a series of tones known as partials or harmonics are generated.

"This atonal strike sound includes many inharmonic that die out quickly, giving way to a strike note or strike tone that is dominated by the prominent partials of the bell. Most observers identify the metallic strike note as having a pitch at or near the frequency of the strong second partial (prime or fundamental), but to others its pitch is an octave higher. Finally, as the sound of the bell ebbs, the slowly decaying hum tone (an octave below the prime, see subharmonic) lingers on." "When a bell is properly struck, the first note that prominently attracts the attention of the ear is what is known as the strike note, tap note, or fundamental, this is what we call the note of the bell. The low sound heard after the strike note has lost its intensity is called the hum. There are also present a minor third and perfect fifth in the first octave, and a major third and perfect fifth in the second octave."

Regarding their names: "When struck by its clapper, a bell vibrates in a complex way...In general, each normal mode of vibration contributes one partial to the sound of the bell. These partials are customarily given names such as hum, prime, minor third (or tierce), fifth (or quint), octave (or nominal), upper octave, etc. The strike note of the bell, which is determined by three partials (the octave, upper fifth, and the upper octave), is generally close to the pitch of the prime in a well-tuned bell." Bells with good tone are well-tuned.

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Wikipedia