AES Munich 2009
Paper Session P19
Event, Stage, and Sound Reinforcement
Saturday, May 9, 13:30 — 15:00
Chair: Francis Rumsey, University of Surrey - Guildford, Surrey, UK
P19-1 Comparative Evaluation of Howling Detection Criteria in Notch-Filter-Based Howling Suppression—Toon van Waterschoot, Marc Moonen, Katholieke Universiteit Leuven - Leuven Belgium
Notch-filter-based howling suppression (NHS) is one of the most popular methods for acoustic feedback control in public address and hands-free communication systems. The NHS method consists of two stages: howling detection and notch filter design. While the design of notch filters is based on well-established filter design techniques, there is little agreement in the NHS literature on how the howling detection subproblem should be tackled. Moreover, since the NHS literature mainly consists of patents, only few experimental results have been reported. The aim of this paper is to describe a unifying framework for howling detection and to provide a comparative evaluation of existing and novel howling detection criteria.
Convention Paper 7752 (Purchase now)
P19-2 Professional Wireless Microphone Systems: Current Situation and Upcoming Changes in Regulatory Issues in Europe and USA—Frank Ernst, Beyerdynamic GmbH & Co. KG - Heilbronn, Germany
Professional wireless microphones have been in use for almost 50 years now. The operation is based on a frequency sharing with TV broadcast transmitters. With the transition to digital TV, this situation changes. Digital TV is more spectrum efficient. After the transition is completed, areas of the spectrum, will be cleared from TV broadcast and will be available for new services. These cleared spectrum areas are referred to as “digital dividend” or white spaces. By the allocation of these bands to other services, valuable resources for the operation of professional wireless microphones will be lost. This paper will give an overview on the current situation for professional wireless microphones and the upcoming changes with the transition to digital TV.
Convention Paper 7753 (Purchase now)
P19-3 Sound Field Reconstruction: An Improved Approach for Wave Field Synthesis—Mihailo Kolundzija, Christof Faller, Ecole Polytechnique Fédérale de Lausanne - Lausanne, Switzerland; Martin Vetterli, Ecole Polytechnique Fédérale de Lausanne - Lausanne, Switzerland, University of California at Berkeley, Berkeley, CA, USA
Wave field synthesis (WFS) is a prevalent approach to multiple-loudspeaker sound reproduction for an extended listening area. Although powerful as a theoretical concept, its deployment is hampered by practical limitations due to diffraction, aliasing, and the effects of the listening room. Reconstructing the desired sound field in the listening area, accounting for the medium propagation characteristic, is another approach termed as sound field reproduction (SFR). It is based on the essential band-limitedness of the sound field, which enables a continuous matching of the reconstructed and the desired sound field by their matching on a discrete set of points spaced below the Nyquist distance. We compare the two approaches in a common single-source free-field setup, and show that SFR provides improved sound field reproduction compared to WFS in a wide listening area around a defined reference line.
Convention Paper 7754 (Purchase now)