Filter and correction for a hybrid sound field analysis of geometrical and wave-based acoustics

Abstract

Statistical, geometrical, or wave-based acoustics are used as the basis for sound field analysis of buildings. As each technique has its own merits and limitations, it is imperative to select a suitable method for the target space and frequency. However, different techniques can be combined to obtain a precise wideband solution. Herein a hybrid technique, which combines the calculated results using the back-tracing method and the finite-difference time-domain (FDTD) method, is proposed to realize a wideband impulse response. Additionally, the required filters and corrections to properly combine the results are discussed. Then the effectiveness of the hybrid technique is evaluated from the viewpoints of required memory and computational time. Compared to the back-tracing method alone, the hybrid technique significantly improves the time and frequency response results, especially at low frequencies. Finally, the appropriate crossover frequency for hybrid analysis is discussed.