Crossover frequency between geometric acoustics and wave-based simulations: perceptual study

Acoustic simulation and auralization are important tools for predicting the acoustic environment before construction. Today we use two main approaches for simulating room acoustics, namely geometrical acoustics (GA) and wave-based methods (WBM). The often-favored GA methods show inaccuracy in small spaces at low frequencies where the wave-phenomena play a larger role.

Solving the wave-equations using numerical WBM can provide more accurate results, but due to expensive computations it is often deselected. In an attempt to combine GA and WBM, we investigated the perceptual crossover frequency that has little to no audible difference between the two auralizations. We used ODEON for a GA method, and discontinuous Galerkin finite element method for WBM.

A listening test was performed on 9 subjects whose task was to evaluate octave-band filtered speech and music stimuli in two rooms via a 3-alternative forced choice test: a small rectangular room and an L-shaped room. The results reveal that the monaural auralizations from the two simulation schemes are perceived differently although the reverberation time and clarity indices are within the just noticeable differences.