Abstract:

This work presents an extension to a measurement technique that was used to estimate the reflection and transmission functions of musical instrument bells, to be used within the context of a parametric waveguide model. In the original technique, several measurements are taken of a system, a 2-meter long cylindrical tube with a speaker and co-located microphone at one end, having incrementally varying termination/boundary conditions. Each measured impulse response yields a sequence of multiple evenly spaced arrivals, from which estimates of waveguide element transfer functions, including the bell reflection and transmission, may be formed. The use of the technique for measuring the saxophone presents difficulties due to 1) the inability of separating the bore from the bell for an isolated measurement, 2) the length of the saxophone producing impulse response arrivals that overlap in time (and are not easily windowed), and 3) the presence of a junction when appending the saxophone to the measurement tube and the spectral ``artifact'' generated as a result. In this work we present a different post signal processing technique to overcome these difficulties while keeping the hardware the same. The result is a measurement of the saxophone's round-trip reflection function which is used to construct its transfer function–-the inverse transform of which yield's the instrument's impulse response.