Article
Time-Domain Local Wave Field Synthesis of Virtual Plane Waves: A Further Development (en)
* Presenting author
Abstract:
This paper introduces an update on the plane-wave driving function for local wave field synthesis. We consider the spatial band-limitation approach, where the driving function is expressed in the spherical harmonic domain up to a finite order. This modal truncation reduces the spatial aliasing artifacts occurring around the center of expansion, thereby achieving an improved synthesis within the local area. The wave field synthesis driving function requires a spatial windowing that is applied to the spatial impulse response of the virtual source evaluated at the loudspeaker positions. In the authors' previous work, the spatial windowing was performed in the modal domain, where the modal coefficients of the spatial window and the spatial impulse response are convolved. Since the spatial window function exhibits an infinite modal bandwidth, approximation errors are inevitable due to modal truncation. In this paper, we replace the spatial window with an equivalent temporal window. The target sound field, i.e. the spatially band-limited plane wave, is expressed by means of plane wave expansion. The direction-of-arrival and time-of-arrival of the individual plane waves are used to derive the equivalent temporal window function in closed form. The latter is applied straightforwardly in the time domain.