Estimation of the Source-Filter Model Using Temporal Dynamics

Sound production process is often expressed by a source-filter model, which assumes that sound signals are generated by convolution of a source signal and a synthesis filter. Although the source-filter model has been widely used, simultaneous estimation of source signals and synthesis filters is difficult due to its inherent indeterminacy. To reduce the indeterminacy, we propose a state-space model that utilizes temporal continuity of pitch and loudness. From the assumption that the synthesis filter contains the timbre-like instrument-specific features while the source signal represents time-variant components such as pitch and loudness, we can estimate the parameters of the synthesis filter and use them for instrument identification. The instrument identification experiments showed comparable or higher accuracy than the existing instrument identification methods with less number of parameters. This result supports the possibility to develop a reliable estimation method of a dynamic source-filter model.