Resonator

I bet you'd never heard of a Stroh violin before Tom Waits dug it back up! Anyway, it used a large metal horn as its resonator instead of a wooden box so it could be picked up better by recording equipment before the late 1920s.

The human vocal instrument has the three elements common to all musical instruments,—a motor, a vibrator, and a resonator; to which is added—what all other instruments lack—an articulator.