Sound field evaluation using auditory filter: Application of dynamic compressive gammachirp filter

The application of dynamic compressive gammachirp filter (dcGC filter) in the evaluation of process of impulse responses was discussed. Two filters were used for analysis, the conventional octave band filter (Oct filter) and the dcGC filter. The filters were applied to the impulse responses. The center frequency of two types of filters was set to 500 Hz, 1,000 Hz, and 2,000 Hz. A contour filter was implemented as the FIR filter, which was used to simulate the outer-and midear transfer functions for preprocessing in the process of dcGC filtering. Two types of filtered signals were then obtained and reverberation curves were calculated by Schroeder integration. The results showed that the reverberation time of the measured studio was around 0.12 to 0.14. The impulse response of the dcGC filter could be time varying depending on the magnitude of the input signal. The gradient obtained using the dcGC filter, particularly in the case of 80 dB, were linearly attenuating and almost parallel with that of the first decay mode in the Oct filter.