New diagnostic system measuring orthogonal factors and calculating subjective attributes of sound fields in a real room

Abstract

Based on the model of the auditory-brain system which consists of the autocorrelation mechanism, the interaural cross-correlation mechanism between the both auditory pathways, and the specialization of human cerebral hemispheres, a new diagnostic system was developed. The system works on a PC for Windows, thus there is no need for special additional devices. After obtaining the impulse response, four orthogonal factors including the SPL, the initial time delay gap between the direct sound and the first reflection, the subsequent reverberation time, and IACC are analyzed for the calculation of the scale values of global and individual subjective preference. In addition to the four factors, two more factors, τIACC and WIACC, in the interaural cross-correlation function are figured out for evaluating the image shift of the sound source and the apparent source width (ASW), respectively. Also, the effective duration, τe, and fine structures of autocorrelation function of sound signals including the value of first maximum, φ1, and its delay time τ1, are analyzed. Keeping the subjectively optimal condition, this system may be utilized for automatic control of sound fields by electroacoustic systems. The new system will be demonstrated at the presentation of this paper. [Work supported by the Ministry of Education, Grant-in-Aid for Scientific Research.]