Importance and representation of phase in the sinusoidal model

In this paper work is presented on the representation and perceptual im-portance of phase. Based on a standard sinusoidal analysis/synthesis system, the phase alignment of the sound components is analyzed. A novel phase representation, partial period phase, is introduced, which characterizes phase evolution over time with an almost stationary parameter for many musical sounds. The proposed partial period phase representation is used to control the phase when synthesizing sounds. Sounds synthesized with varying amount of phase information are compared in a listening experiment with 11 subjects. It is shown that phase is of great importance to the perception of sound quality of common harmonic musical sounds, but indications are found that phase is not of importance to the slightly inharmonic piano sounds. In particular, the sound degradation is large for low-pitched sounds, approaching Slightly An-noying when no phase information is used. In addition, a model based on the partial period phase representation has a significantly better perceived sound quality than sounds with random phase shifts.