Hybrid instruments need a dipole or quadrupole vibrator plus a nearby tuned resonator.

Evidence

An important mechanism for sound production is exploited by the marimba, Indonesian angklung, and wind chimes, to name a few. It is the basis for several demonstrations using resonators to amplify sound, such as Savart’s cup (Felix Savart, 1791–1841), discussed here, and a tuning fork set atop a resonator. The common elements shared by this diverse group of hybrid sound producers include a mechanical dipole or quadrupole vibration of a solid object like a tuning fork or a bowl, and a tuned resonator, which must be held close to the vibrating object—that is, close compared to a wavelength of the sound being produced. — Eric J. Heller, Why You Hear What You Hear- An…, 1876

Categorization

• DEFINE: States the defining two-part mechanism shared by marimba, angklung, wind chimes, and Savart’s cup.