Estimating the clarinet mouthpiece reflection from measurement and the instrument's produced sound

In this work, a method is presented for estimating the reflection off the clarinet mouthpiece, using a priori measurement of the bell, and post processing of the instrument's produced sound. A previously introduced measurement technique is used to obtain measurement of clarinet bell and transmission filters. In addition to these elements, however, the round-trip propagation loss in the clarinet bore and bell also includes wall loss and mouthpiece reflection. Though the former is accurately modeled theoretically, assuming the clarinet bell is close to cylindrical, the mouthpiece is more difficult to measure, both because of a supposed oscillating reed, and because the required placement of a measurement device would obstruct the mouthpiece's characteristic reflection. The lumped round-trip loss filter in the bore is estimated from the clarinet signal by first considering the signal's periodic structure. After taking the signal's autocorrelation, which preserves its periodicity and naturally provides the beginning of the period, the round-trip filter is iteratively estimated by constructing an optimization function from the first and second phases of the autocorrelation sequence. Once the round-trip loss is estimated, the mouthpiece reflection may be extracted by removing the effect of the other known comprising filter elements.