Video analysis and modeling of the kalimba tine

The kalimba, like the more traditional mbira, uses plucked metal tines mounted to a wood resonator. The mounting is similar to a three point flexural test and provides an initial strain to part of the tine. The plucked end of the tine is free once released, but modeling the other end is less obvious. The motion of the longest tine of the treble kalimba (B3, 247 Hz) was captured via high speed video (1200 f.p.s.). Analysis of tine displacement informed the boundary conditions of an Euler–Bernoulli model for this thin beam vibration, which in turn predicted mode shapes and frequencies. The two lowest mode frequencies can be compared to prominent features in the spectrogram of recorded tones. Rapidly decaying harmonic content observed in the spectrogram is not suggested by this simple model; a more sophisticated approach is required to fully understand the behavior of the kalimba tine.