Abstract: An improved percussive instrument such as a marimba employs a resonator comprising an external tube (100), an inner or virtual extender tube (115), and a bottom stop (105) and a plug (110) within the outer tube. The region between the external tube and the virtual extender tube defines a volume of air (116). The size, shape, and length of the virtual extender tube enhances performance of the resonator and thereby also the instrument. A key (800) of the instrument is suspended by pivots (805) above the plug and the opening (120) of the resonator. When struck by a mallet (810), the key vibrates and air driven by the key enters the resonator through the opening. When the resonator and key are tuned to the same frequency, or a harmonic thereof, air will enter and leave the resonator in a resonant fashion, creating louder and richer sounds than just the key alone. Numerous variations on shape and location of the various components are possible.