Analysis on the Timbre of Ambisonics Repro- Dution Using a Binaural Loudness Model

Ambisonics are a series of flexible sound reproduction systems that decompose and reconstruct sound field by each order approximation of horizontal Fourier or spatial spherical harmonics decomposition. For a given order reproduction, providing that the product of wave number and the radius of the rendering region is approximately less than the order, the system is able to recreate the target sound field with reasonable accuracy. If the condition of accurate reproduction is not satisfied, spatial aliasing and interference occur in the reproduced sound field, which inevitably change the timbre in reproduction. The present work analyzes the timbre in Ambisonics reproduction using Moore’s binaural loudness model, and the binaural loudness level spectra is used as a criterion to evaluate the timbre in reproduction. The results indicate that, increasing of frequency or deviation from central listening position may break down the condition of accurate reproduction, accordingly result in change in binaural loudness level spectra and perceived timbre. Increasing order of system reduces the change in binaural loudness level spectra and improves the timbre.