AES Munich 2009
Paper Session P8
Friday, May 8, 09:00 — 11:30
Chair: Ronald M. Aarts
P8-1 Phase Velocity and Group Velocity in Cylindrical and Spherical Waves—Ian M. Dash, Australian Broadcasting Corporation - Sydney, NSW, Australia; Fergus R. Fricke, University of Sydney - Sydney, NSW, Australia
Closed-form expressions are derived for phase velocity and group velocity in cylindrical and spherical sound waves. These are plotted and compared for orders 0, 1, and 2, but the expressions are general and may be applied to waves of any order. Dispersion characteristics of these waves are examined and discussed. The implications for thermodynamic applicability of the wave equation and for application of Huygens’ principle are discussed.
Convention Paper 7693 (Purchase now)
P8-2 Selection of Loudspeaker Positions for Reverberation Time and Sound Field Measurements—Elena Prokofieva, Napier University - Edinburgh, UK
According to the various building standards, the source loudspeakers and receiving microphones during the internal noise level measurements can be placed “in any convenient position,” with just some distance restrictions from the nearest reflecting surfaces. In rooms of different shapes and volumes the location of the source and receiver microphone may significantly affect the measured results. If the difference between the reverberation times or noise levels measured for two positions in the same room exceeds 10 percent, they cannot be averaged. The simulation program is created to recommend the most suitable locations for microphone and loudspeakers in tested room for reverberation time measurements. The results of series of tests are analyzed to confirm the results of the simulation.
Convention Paper 7694 (Purchase now)
P8-3 A Rehearsal Hall with Virtual Acoustics for Symphony Orchestras—Tapio Lokki, Jukka Pätynen, Helsinki University of Technology - Espoo, Finland; Timo Peltonen, Olli Salmensaari, Akukon Consulting Engineers Ltd. - Helsinki, Finland
A solution for constructing a small rehearsal hall, the acoustics of which resembles the stage of a large concert hall is presented. The implemented system was evaluated both objectively with measurements and subjectively by collecting feedback from musicians. The subjective opinions were very positive and encouraging and the main objective was achieved. The electroacoustically enhanced rehearsal space sounded like a much bigger hall, although the sound pressure level increased less than one decibel. The presented solution is applicable in all spaces, which are not very reverberant by nature and where the height of the room is at least twice the standard room height.
Convention Paper 7695 (Purchase now)
P8-4 Sound Field Characterization and Absorption Measurement of Wideband Absorbers—Soledad Torres-Guijarro, Laboratorio Oficial de Metroloxía de Galicia (LOMG) - Ourense, Spain; Antonio Pena, Alfonso Rodríguez-Molares, Norberto Degara-Quintela, Universidad de Vigo - Vigo, Spain
Wideband absorbers are a fundamental part of non-environment control rooms. They consist of huge angled hanging panels in conjunction with a multilayer wall or ceiling. Their absorption capacity is very noticeable, mostly in the low frequency range. In this paper the mechanisms of absorption of the wideband absorbers of the rear wall of the control room at the Universidad de Vigo will be studied. Conclusions will be drawn from the analysis of pressure, velocity volume, and intensity measurements performed in the vicinity of the panels, and from the computation of the normal specific acoustic impedance and the normal absorption coefficient.
Convention Paper 7696 (Purchase now)
P8-5 Temporal Matching of 2-D and 3-D Wave-Based Acoustic Modeling for Efficient and Realistic Simulation of Rooms—Jeremy J. Wells, Damian T. Murphy, Mark Beeson, University of York - York, UK
Methods for adapting the output of a two-dimensional Kirchoff-variable digital waveguide mesh to better match that of a 3-D mesh, both of which are intended to model the same acoustic space, are presented. Details of the methods, including quality of output and computational demands, are given along with the details of how they are incorporated into the hybrid system within which they are employed.
Convention Paper 7697 (Purchase now)