A hammer deposits its energy based only on local deformations, before returning echoes.

Evidence

A hammer rebounds from a bell surface (see figure 11.1) long before the disturbance has traveled around the bell and back to the point of the hammer blow. Thus the total amount of energy deposited by the hammer is decided in an instant, on the basis of very local deformations, independent of any details farther away. The fixed amount of energy deposited by the hammer is shared over the whole power spectrum. — Eric J. Heller, Why You Hear What You Hear- An…, 1077

Categorization

• XREF: Explains why striking a bell’s nodal point leaves it silent — total energy decided at the instant of local impact, so global geometry never enters the energy budget. Ties to how percussionists tune drums and xylophones.