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Last Updated: 20070320, meiP16 - Room and Architectural Acoustics and Sound Reinforcement
Monday, May 7, 09:30 — 11:00
P16-1 Acoustic Treatment of the Regional Flight Control Center Hall in Zagreb, Croatia—Marko Horvat, Hrvoje Domitrovic, Sanja Grubesa, University of Zagreb - Zagreb, Croatia
Acoustic treatment has been realized in the hall of Regional Flight Control Center in Zagreb, Croatia, upon complaints made by the flight control operators working in the mentioned hall. The primary complaint was that the operators could hear each other too well across the hall, due to unwanted reflections, so the main task was to reduce those reflections. The emphasis was also made on reducing the reverberation time of the hall, proven to be too long for the size and intended purpose of the hall, thereby reducing the background noise level in the hall as well.
Convention Paper 7086 (Purchase now)
P16-2 Investigating Classroom Acoustics by Means of Advanced Reproduction Techniques—Nicola Prodi, Andrea Farnetani, University of Ferrara - Ferrara, Italy; Yuliya Smyrnova, University of Ferrara - Ferrara, Italy and Polish Academy of Sciences, Poland; Janina Fels, RWTH Aachen University - Aachen, Germany
A research was undertaken to investigate the loss of Italian language word intelligibility in classrooms caused by low signal to noise ratio and too high reverberation. In the first part of the paper, impulse responses and background noises were measured in two primary schools using different mono, binaural, and B-format probes. A dummy head with child morphology was also used for the first time in this context. It was thus possible to compare the performance of a child head to the conventional adult one. Then the restitution of the recorded sound fields in a dedicated listening room was accomplished, using stereo dipole and ambisonics technologies.
Convention Paper 7087 (Purchase now)
P16-3 Perception of Concert Hall Acoustics in Seats Where the Reflected Energy Is Stronger than the Direct Energy—David Griesinger, Harman Specialty Group - Bedford, MA, USA
This paper describes a series of experiments into sound perception when the direct/reverberant ratio (d/r) is low. Sound source localization and the perception of being adequately close to the musicians are improved when the direct sound dominates the total reflected energy for about 40 ms, during which time the direct sound can be separately perceived. For such a hall the impressions of loudness, clarity, and localization are satisfactory and nearly unchanged over a 6 dB range of d/r. As the time period of direct sound dominance decreases, the d/r ratio must be higher for equal subjective clarity.
Convention Paper 7088 (Purchase now)
P16-4 Relation between Correlation Characteristics of Sound Field and Width of Listening Zone—Elena Prokofieva, Linn Products Ltd. - Glasgow, Scotland, UK
The principal features of an even sound field are large directivity and diffusive nature of the radiated field. Directivity pattern of stereo loudspeakers was analyzed to determine the degree of coherence of the sound field in the room. Measurements of the sound field in close to a standard listening room conditions were conducted with the loudspeakers placed in ITU-recommended and specially selected positions. The results showed that the radius of correlation corresponds to the size of the sweet spot. Relocating loudspeakers in the room and taking into consideration the room environment influence can help to enlarge the listening zone within the room. These conclusions were confirmed by listening tests and recommendations on sound field correlation can be established.
Convention Paper 7089 (Purchase now)
P16-5 On the Implementation of a Room Acoustics Modeling Software Using Finite-Differences Time-Domain Method—José Lopez, Technical University of Valencia - Valencia, Spain; José Escolano, Technical University of Jaen - Linares (Jaen), Spain; Basilio Pueo, University of Alicante - Alicante, Spain
The Finite-Difference Time-Domain (FDTD) approximation method has been introduced into acoustics in the last years to solve field problems numerically. However, the huge amount of computer power needed to be used in the modeling of large rooms has delayed the launch of commercial applications, being the major part based on ray-tracing. This paper analyzes the viability of a FDTD implementation for this task in today’s personal computers and presents the resulting application. All simulation stages from the architectural model, the generation of the mesh, implementation of the recursion, parallelization, and, finally, the result in the form of impulse response are discussed.
Convention Paper 7090 (Purchase now)