Gentle Acoustic Crosstalk Cancelation using the Spectral Division Method and Ambiophonics

ABSTRACT We propose the concept of gentle acoustic crosstalk cancelation, which aims at reducing the crosstalk between a loudspeaker and the listener's contralateral ear instead of eliminating it completely as aggressive methods intend to do. The expected benefit is higher robustness and a tendency to collapse less unpleasantly. The proposed method employs a linear loudspeaker array and exhibits two stages: 1) Use the Spectral Division Method to illuminate the ipsilateral ear using constructive interference of the loudspeaker signals. This approach provides only little channel separation between the listener's ears at frequencies below approximately 2000 Hz. 2) There we additionally use destructive interference by Recursive Ambiophonics Crosstalk Elimination (RACE). RACE was chosen because of its tendency to collapse gently. In a sample scenario with realistic parameters, the proposed method achieves around 20 dB of channel separation between 700 Hz and 9000 Hz, which appears to be sufficient to achieve full perceived lateralization when only one ear is illuminated

Efficient implementation of the spectral division method for arbitrary virtual sound fields

The Spectral Division Method is an analytic approach for sound field synthesis that determines the loudspeaker driving function in the wavenumber domain. Compact expressions for the driving func-tion in time-frequency domain or in time domain can only be deter-mined for a low number of special cases. Generally, the involved spatial Fourier transforms have to be evaluated numerically. We present a detailed description of the computational procedure and minimize the number of required computations by exploiting the following two aspects: 1) The interval for the spatial sampling of the virtual sound field can be selected for each time-frequency bin, whereby low time-frequency bins can be sampled more coarsely, and 2) the driving function only needs to be evaluated at the lo-cations of the loudspeakers of a given array. The inverse spatial Fourier transform is therefore not required to be evaluated at all ini-tial spatial sampling points but only at those locations that coincide with loudspeakers. Index Terms — Spectral Division Method, loudspeaker array, spatial Fourier transfor