2011 年 30 巻 1 号 p. 97-102
At present, environmental noises are evaluated by sound intensity such as equivalent continuous A-weighted sound pressure level (L_<Aeq>). However, we sometimes feel annoyed with sound with low sound intensity because of the quality. Sound quality can be characterized by factors obtained from autocorrelation (ACF) and interaural cross-correlation function (IACF) of sounds. For example, pitch and pitch strength can be characterized by the delay time (τ_1) and amplitude of the maximum peak (φ_1) of the ACF. Directional sensation can be characterized by the delay time (τ_<IACC>) and amplitude of the maximum peak (IACC) of the IACF. We utilized ACF and IACF factors as means to evaluate artificial and environmental noises. The results suggest that the effective duration of the ACF, τ_1, φ_1, and IACC are useful criteria for evaluating noise.