A Resonance Box is usually constructed of wood; it may be open at one or both ends, and must be of such dimensions that the enclosed mass of air will vibrate in unison with the tuning fork to be applied to it.
See Also
07 - Resonance Co-vibration or Sympathy of Tones
Bell Resonance
Resonance
Sympathetic Resonance
Tuning Fork
Volumetric Resonator