Synthesis of a spatially band-limited plane wave in the time-domain using wave field synthesis

Hahn, Nara; Winter, Fiete; Spors, Sascha

doi:10.23919/eusipco.2017.8081292

Cited by 6 publications

(7 citation statements)

References 13 publications

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“…3(b)]. This problem was reported in [22], where the cylindrical radial filters were used for the WFS driving functions. In order to reduce the spectral deviations, a heuristically chosen nonlinear amplitude mapping was applied to the time-domain radial functions.…”

Section: Radial Filter Designmentioning

confidence: 97%

“…The design of cylindrical radial filters in the time domain has been relatively unexplored. Although the explicit expressions for the time-domain radial functions are known [22], it is not trivial to achieve a reasonable spectral accuracy. This is mainly because of the slow decay of the spectrum toward high frequencies, which causes strong aliasing artifacts if sampled in the time domain.…”

Section: Introductionmentioning

confidence: 99%

“…The straightforward solution of increasing the sampling rate comes at the expense of computational cost. In [22], a nonlinear amplitude mapping was applied to the time-domain cylindrical radial functions. Although the aliasing distortion can be effectively reduced, the nonlinear mapping function has to be chosen heuristically.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cylindrical Radial Filter Design With Application to Local Wave Field Synthesis

Hahn¹,

Schultz²,

Spors³

2022

J. Audio Eng. Soc.

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The cylindrical radial filters refer to the discrete-time realizations of the radially dependent parts in cylindrical harmonic expansions, which are commonly described by the cylindrical Bessel functions. An efficient and accurate design of the radial filters is crucial in spatial signal processing applications, such as sound field synthesis and active noise control. This paper presents a radial filter design method where the filter coefficients are analytically derived from the time-domain representations. Time-domain sampling of the cylindrical radial functions typically leads to spectral aliasing artifacts and degrades the accuracy of the filter, which is mainly attributed to the unbounded discontinuities exhibited by the time-domain radial functions. This problem is coped with by exploiting an approximation where the cylindrical radial function is represented as a weighted sum of the radial functions in spherical harmonic expansions. Although the spherical radial functions also exhibit discontinuities in the time domain, the amplitude remains finite, which allows application of a recently introduced aliasing reduction method. The proposed cylindrical radial filter is thus designed by linearly combining the spherical radial filters with improved accuracy. The performance of the proposed cylindrical radial filters is demonstrated by examining the spectral deviations from the original spectrum.

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Section: Radial Filter Designmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Cylindrical Radial Filter Design With Application to Local Wave Field Synthesis

Hahn¹,

Schultz²,

Spors³

2022

J. Audio Eng. Soc.

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“…3]. The focus of this paper is on the second approach which exploits analytical time-domain solutions to the wave equation [25,[33][34][35]. This is appropriate for homogeneous wave fields where the spatio-temporal impulse responses have a compact support in time.…”

Section: Introductionmentioning

confidence: 99%

Time Domain Sampling of the Radial Functions in Spherical Harmonics Expansions

Hahn

Schultz

Spors

2021

IEEE Trans. Signal Process.

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Spherical harmonics representations are widely adopted in applications such as analysis, manipulation, and synthesis of wave fields that are either captured or simulated. Recent studies have shown that, for broadband fields, a time domain representation of spherical harmonics expansions can benefit from computational efficiency and favorable transient properties. For practical usage, an accurate discrete-time modeling of spherical harmonics expansions is indispensable. The main challenge is to model the so called radial functions which describe the radial and frequency dependencies. In homogeneous cases, they are commonly realized as finite impulse response filters where the coefficients are obtained by sampling the continuoustime representations. This article investigates the temporal and spectral properties of the resulting discrete-time radial functions. The spectral distortions caused by aliasing are evaluated both analytically and numerically, revealing the influence of the distance from the expansion center, sampling frequency, and fractional sample delay. It is also demonstrated how the aliasing can be reduced by employing a recently introduced band limitation method.Index Terms-Radial filter, radial function, time-domain spherical harmonics expansion, time dependent wave field

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“…In recent years, much research effort has also been invested in personalized audio reproduction, i.e., synthesizing individualized acoustic scenes for multiple listeners in different areas of the reproduction room [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. A prominent use case is given in cars, where the driver could listen to the information provided by a navigation system while all passengers can enjoy their favorite audio content.…”

Section: Introductionmentioning

confidence: 99%

Broadband multizone sound rendering by jointly optimizing the sound pressure and particle velocity

Buerger

Hofmann

Kellermann

2018

The Journal of the Acoustical Society of America

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In this paper, a recently proposed approach to multizone sound field synthesis, referred to as joint pressure and velocity matching (JPVM), is investigated analytically using a spherical harmonics representation of the sound field. The approach is motivated by the Kirchhoff-Helmholtz integral equation and aims at controlling the sound field inside the local listening zones by evoking the sound pressure and particle velocity on surrounding contours. Based on the findings of the modal analysis, an improved version of JPVM is proposed, which provides both better performance and lower complexity. In particular, it is shown analytically that the optimization of the tangential component of the particle velocity vector, as is done in the original JPVM approach, is very susceptible to errors and thus not pursued anymore. Furthermore, the analysis provides fundamental insights as to how the spherical harmonics used to describe three-dimensional sound fields translate into two-dimensional basis functions as observed on the contours surrounding the zones. By means of simulations, it is verified that discarding the tangential component of the particle velocity vector ultimately leads to an improved performance. Finally, the impact of sensor noise on the reproduction performance is assessed.

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Synthesis of a spatially band-limited plane wave in the time-domain using wave field synthesis

Cited by 6 publications

References 13 publications

Cylindrical Radial Filter Design With Application to Local Wave Field Synthesis

Cylindrical Radial Filter Design With Application to Local Wave Field Synthesis

Time Domain Sampling of the Radial Functions in Spherical Harmonics Expansions

Broadband multizone sound rendering by jointly optimizing the sound pressure and particle velocity

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