Analysis of Harmonic and Subharmonic Effects in a Transversal Flute Made from Heracleum Laciniatum

In this paper, we present an analysis of recordings of a transversal flute made from the dried stem of the Heracleum laciniatum (Tromsø Palm or Hogweed). While the lower octave exhibits conventional harmonic spectra, the upper octave surprisingly includes subharmonic components. We believe that the subharmonic contributions are due to nonlinear oscillations of the flute material. A time-frequency analysis of the onset of the sound, shows that the subharmonic oscillators are present from the very beginning, as opposed to the higher harmonics. A bispectral analysis indicates that triplets of frequency components are phase locked.