Estimating the Reed Pulse from Clarinet Recordings

In this work we estimate the volume flow pulses through a clarinet reed from recorded clarinet signal. The idea is similar to extracting glottal pulse sequences from recorded speech, however since the clarinet reed has little mass and generates significant reflection, the source-filter model used in speech processing invalid. Here, the clarinet is modeled as a pressure-controlled valve coupled to a bi-directional waveguide, with the output pressure seen as a linear time invariant transformation of reed volume flow. By noting that pressure waves will make two round trips from the mouthpiece to the bell and back for each reed pulse, a predictor is developed which operates on the recorded data in order to estimate the round-trip attenuation experienced by pressure waves in the instrument. Combining these losses with the direct measurements of the bell reflection function, a filter is developed which inverts the implied waveguide to reveal the reed volume flow pulses.