Optimizing Source and Sensor Placement for Sound Field Control: An Overview

International audienceIn order to control an acoustic field inside a target region, it is important to choose suitable positions of secondary sources (loudspeakers) and sensors (control points/microphones). This paper provides an overview of state-of-the-art source and sensor placement methods in sound field control. Although the placement of both sources and sensors greatly affects control accuracy and filter stability, their joint optimization has not been thoroughly investigated in the acoustics literature. In this context, we reformulate five general source and/or sensor placement methods that can be applied for sound field control. We compare the performance of these methods through extensive numerical simulations in both narrowband and broadband scenarios. Index Terms-source and sensor placement, sound field control , sound field reproduction, subset selection, interpolation

Two-Dimensional Spatial Control using Multiple Circular Loudspeaker Arrays and Elliptical Loudspeaker Array

電気通信大学202

Sound field synthesis for line source array applications in large-scale sound reinforcement

The thesis deals with optimized large-scale sound reinforcement using line source arrays. This is treated as a sound field synthesis problem. The synthesis of a virtual source via the line source array allows for audience adapted wavefront shaping. For practical array designs and setups this is affected by the deployed loudspeakers and their arrangement, its electronic control and spatial aliasing occurrence. The influence of these parameters is discussed with array signal processing revisiting the Wavefront Sculpture Technology and proposing Wave Field Synthesis as a suitable control method.Die Arbeit beschäftigt sich mit optimaler Beschallung großer Auditorien mit Line Source Arrays. Das Problem wird mit Schallfeldsynthese beschrieben. Die Synthese einer virtuellen Quelle mit einem Line Source Array ermöglicht eine für das Auditorium angepasste Wellenfront. In der Praxis wird dies beeinflusst von den verwendeten Lautsprechern, ihrer Anordnung, ihrer Ansteuerung und räumlichem Aliasing. Der Einfluss der Parameter wird mit Array-Signalverarbeitung diskutiert, wofür Wavefront Sculpture Technology aufgegriffen und Wellenfeldsynthese als Ansteuerungsmethode vorgeschlagen wird

Comparison of sound reproduction using higher order loudspeakers and equivalent line arrays in free-field conditions

Higher order sound sources of Nth order can radiate sound with 2N + 1 orthogonal radiation patterns, which can be represented as phase modes or, equivalently, amplitude modes. This paper shows that each phase mode response produces a spiral wave front with a different spiral rate, and therefore a different direction of arrival of sound. Hence, for a given receiver position a higher order source is equivalent to a linear array of 2N + 1 monopole sources. This interpretation suggests performance similar to a circular array of higher order sources can be produced by an array of sources, each of which consists of a line array having monopoles at the apparent source locations of the corresponding phase modes. Simulations of higher order arrays and arrays of equivalent line sources are presented. It is shown that the interior fields produced by the two arrays are essentially the same, but that the exterior fields differ because the higher order sources produces different equivalent source locations for field positions outside the array. This work provides an explanation of the fact that an array of L Nth order sources can reproduce sound fields whose accuracy approaches the performance of (2N + 1)L monopoles

Local sound field synthesis

This thesis investigates the physical and perceptual properties of selected methods for (Local) Sound Field Synthesis ((L)SFS). In agreement with numerical sound field simulations, a specifically developed geometric model shows an increase of synthesis accuracy for LSFS compared to conventional SFS approaches. Different (L)SFS approaches are assessed within listening experiments, where LSFS performs at least as good as conventional methods for azimuthal sound source localisation and achieves a significant increase of timbral fidelity for distinct parametrisations.Die Arbeit untersucht die physikalischen und perzeptiven Eigenschaften von ausgewählten Verfahren zur (lokalen) Schallfeldsynthese ((L)SFS). Zusammen mit numerischen Simulationen zeigt ein eigens entwickeltes geometrisches Modell, dass LSFS gegenüber konventioneller SFS zu einer genauere Synthese führt. Die Verfahren werden in Hörversuchen evaluiert, wobei LSFS bei der horizontalen Lokalisierung von Schallquellen eine Genauigkeit erreicht, welche mindestens gleich der von konventionellen Methoden ist. Für bestimmte Parametrierung wird eine signifikant verbesserte klangliche Treue erreicht