Timbre replacement of harmonic and drum components for music audio signals

This paper presents a system that allows users to customize an audio signal of polyphonic music (input), without using musical scores, by replacing the frequency characteristics of harmonic sounds and the timbres of drum sounds with those of another audio signal of polyphonic music (reference). To develop the system, we first use a method that can separate the amplitude spectra of the input and reference signals into harmonic and percussive spectra. We characterize frequency characteristics of the harmonic spectra by two envelopes tracing spectral dips and peaks roughly, and the input harmonic spectra are modified such that their envelopes become similar to those of the reference harmonic spectra. The input and reference percussive spectrograms are further decomposed into those of individual drum instruments, and we replace the timbres of those drum instruments in the input piece with those in the reference piece. Through the subjective experiment, we show that our system can replace drum timbres and frequency characteristics adequately.