Excitation signal Extraction for Guitar tones

This paper is concerned with extracting excitation signals from recorded plucked-string sounds from an acoustic guitar. Three pre-existing methods are reviewed: the matrix pencil inverse-filtering (MPIF) method by Laroche and Meillier (1994), the sinusoids plus noise inverse-filtering (SPNIF) method by Välimäki and Tolonen (1998), and the magnitude spectrum smoothing (MSS) method by Laurenti and De Poli (2000). The proposed method in this paper is based on removal of spectral peaks, followed by statistical interpolation to reconstruct the excitation spectrum in frequency intervals occluded by partial overtones. We call this the statistical spectral interpolation (SSI) method. The four methods are compared on synthetic data and data recorded from an acoustic guitar. Results show that the method presented in this paper outperforms previous methods in removing tonal components in the resulting excitation signal while maintaining a noise-burst like quality.