Review of Methods and Final Words

In this reader, we discuss methods for decomposing a plucked stringed-instrument into modular components with individual properties that can be measured, modeled and calibrated. Within calibration, there are just a few overarching themes that should be mentioned to add cohesion to the methods presented. Inverse-filtering, used to reduce the order of measured body impulse responses and pressure radiation transfer functions, is extrememly useful in removing unwanted components within a given signal. However, there are conditions with which its method creates undesireable side-effects: nulls within the spectrum. As discussed in obtaining excitations for the digital waveguide string models in Section 4.1, using inverse-filtering causes nulls at the fundamental and its harmonics resulting in an anti-harmonic excitation. Since the excitation of the string is flat-spectrummed, inverse-filtering methods for excitation extraction does not present a psycho-acoustically pleasing solution.