Monaural Phase Effects on Timbre of Two-Tone Signals

The effects of the phase difference between components of a two-tone signal whose components have a frequency ratio of f₂/f₁ = 2.0 on its timbre were investigated. In the experiments, the similarities among six signals were judged with the complete method of triads. The subjective space in which the configuration of points with the different phase conditions lay was derived from the data by means of Torgerson's multidimensional scaling program. An early study stated that the subjective space was a circle. Present results, however, revealed that the subjective space becomes one-dimensional when either the amplitude ratio between components was large or when the frequency of the signal was high. This one-dimensional configuration is interpreted in terms of the partially masked loudness of the higher frequency component of the signal.