Improved Time-Efficiency in Continuous Measurement of Spatial Room Impulse Responses by Dual-Band Excitation
* Presenting author
In a continuous measurement, a large number of spatial impulse responses are obtained by using a moving microphone. As shown in previous studies, the signal captured by the microphone is a spatio-temporal sampling of the sound field, and thus the system identification constitutes a spatial interpolation process. The effective number of spatial sampling points is given as the total duration of the measurement divided by the period of the excitation signal. To avoid temporal aliasing, the excitation period has to be longer than any impulse response of the system. Since the microphone speed determines the density of the sampling points, it has to be chosen carefully by taking the wavelength at the highest temporal frequency into account. This results in an oversampling in low frequencies. In this paper, the time-efficiency is improved by performing the measurement separately for different frequency bands. In the low-pass filtered band, the microphone speed can be increased without causing spatial aliasing. In the high-pass filtered band which exhibits a high decay rate, a shorter excitation period can be used which allows a faster movement without losing spatial resolution. The improved time-efficiency of the proposed approach is demonstrated by numerical simulations.