Integration of DSP algorithms and musical constraints for the separation of partials in polyphonic music

We illustrate how high-level knowledge from the musical domain may be integrated with sophisticated signal processing algorithms within a system for separating possibly overlapping partial frequency components from polyphonic music. Musical knowledge utilized in our system is in the form of constraints on the time-frequency behavior of musical signals such as the frequency locations of notes on the western musical scale and the presence or absence of vibrato in each note. For any given signal scenario, these constraints help in appropriately initializing and adjusting a set of algorithms for constant-Q processing, spectral peak picking, and multihypothesis tracking through Kalman filtering. As demonstrated by the evaluation of our system with a variety of signals containing two simultaneously played violin notes, the application of these algorithms results in the accurate separation of individual partials.