Simulated impulse responses of small rooms using hybrid methods : optimizing crossover frequency

Abstract

most accurate physical parameter comparison. Reverberation time, clarity index factors and direct-to-reverberant energy ratio of the simulated impulse response were all within the just-noticeable-difference in the low frequency range, leading towards a perceptual evaluation of the hybrid room impulse responses to validate the accuracy the simulated hybrid room

Finite difference time domain (FDTD) methods are applied for low frequency numerical analysis of Dizzy’s Club Coca-Cola. The FDTD simulation is constructed from a 13-point stencil face-centered cubic grid with a one centimeter grid resolution. The geometrical acoustic analysis is computed using commercially available software. Each impulse is combined at varying crossover frequencies ranging from 50 Hz to 1 kHz, giving a total of 14 hybrid room impulse responses. The evaluation of each hybrid impulse response consists of the physical comparison between calculated hybrid and measured room acoustic parameters. Direct-to-reverberant energy ratio, early-to-late energy ratios, and reverberation times are used for the physical comparison to assess the accuracy and plausibility of each hybrid room impulse response.

Hybrid room impulse response with 100 Hz crossover frequency was found to have the

impulse responses.

Acoustic simulations have become a standard tool in the acoustic design of performance spaces, but nearly all applications have been limited to Western classical music venues. Small rooms, such as jazz clubs, pose very different challenges. With performance spaces exhibiting sub-wavelength dimensions, pure geometrical models are no longer valid. However, computational efficiency has allowed the integration of geometric and wave-based modeling in acoustic simulations. This research aims to vary crossover frequency between the geometric and wave-based models in order to optimize the physical accuracy of the hybrid room impulse responses.