Analysis of piano tones using an inharmonic inverse comb filter

Analysis of piano tones using an inharmonic inverse comb filter
Heidi-Maria Lehtonen
Department of Signal Processing and Acoustics
Helsinki University of Technology
Espoo, Finland
This paper presents a filter configuration for canceling and separating partials from inharmonic piano tones. The proposed configuration is based on inverse comb filtering, in which the delay line is replaced with a high-order filter that has a proper delay characterization. Two filter design techniques are tested with the method: an FIR filter, which is designed using frequency sampling, and an IIR filter, which consists of a set of second-order allpass filters that match the desired group delay. It is concluded that it is possible to obtain more accurate results with the FIR filter, while the IIR filter is computationally more efficient. The paper shows that the proposed analysis method provides an efficient and easy way of extracting the residual signal and selecting partials from piano tones. This method is suitable for analysis of recorded piano tones and for inverse filtering.
The manuscript has been submitted to the International Conference on Digital Audio Effects (DAFx-08) in March 2008.
Sound samples
Author: Heidi-Maria Lehtonen
Modified: April 3, 2008 by Heidi-Maria Lehtonen