Duration Sensation When Listening to Bandpass Noises in a Room
Kazi Saifuddin and Yoichi Ando

In order to attain knowledge evaluating physical environment in term of the duration sensation (DS) subjective judgments with noise stimuli were conducted here. The DS of bandpass noises in a room was examined while changing the factors (t₁, f₁, and t_e) extracted from the autocorrelation function (ACF) under a constant reverberation condition. The white noise and bandpass noises with five center frequencies (250, 500, 1000, 2000, and 4000 Hz) and their selected bandwidths (80, 80, 160, 320 and 640 Hz, respectively) were presented first in the pair. The second stimulus was the white noise alone. In the paired-comparison test, 21 subjects judged whether or not the white-noise duration was longer than the bandpass-noise duration, under the conditions of a constant sound pressure level (SPL; 80 dB(A)). The rise and fall times of the stimuli were 2.5 ms and 51.25 ms, respectively. The results indicated that the DS of bandpass noise was judged to be a longer sensation than that of the white noise. The DSs of the bandpass-noise stimuli with lower pitches (larger t₁) were found to be significantly longer than those of the stimuli with a shorter t₁ (p < 0.01). So, the DS is explained here as one of the primary sensations of the sound stimuli. Another experiment was conducted in which two white-noise stimuli were presented in a pair with different values of F(0) (SPL) extracted from the ACF; otherwise conditions were the same as the above. The results indicated that the DS of white-noise stimulus with a higher F(0) (80 dB(A)) was found to be significantly (p < 0.05) longer duration than one with the lower F(0) (50 dB(A)).

Keywords:
duration sensation, autocorrelation function (ACF)