AES London 2011
Paper Session P11

P11 - Room Acoustics

Saturday, May 14, 14:00 — 17:30 (Room 1)

Diemer de Vries

P11-1 DTS Multichannel Audio Playback System: Characterization and CorrectionZoran Fejzo, DTS, Inc. - Calabasas, CA, USA; James Johnston, DTS, Inc. - Kirkland, WA, USA
Audio playback system correction methods are now commonplace in audio-video receivers. One goal of these systems is to correct deviation of loudspeaker/room frequency response from some desired target curve. Unfortunately this correction may be inappropriate outside of a small area around the microphone location, and averaged measurements may provide unwanted timbre shifts. Some room correction algorithms capture the room responses at multiple locations and combine them to obtain a representative response that is used for frequency correction. We will present a loudspeaker / room correction system that attempts to achieve perceptually appropriate frequency correction in a wide listening area by using a closely spaced non-coincident multi-microphone array placed in a single location in the room. By use of special probe signals, this is achieved within a short measurement period.
Convention Paper 8379 (Purchase now)

P11-2 Evaluating the Auralization of Performance Spaces and Its Effect on Singing PerformanceJudith Brereton, Damian T. Murphy, David M. Howard, University of York - Heslington, York, UK
Musicians alter their performance according to the acoustic environment in which they perform, but as yet a thorough parametric investigation of the effect of room acoustics on musical performance has not yet been achieved. A sufficiently “realistic” synthesized Room Impulse Response (RIR) will facilitate such a study, since this will allow the investigator greater control and knowledge of the room acoustic parameters involved. This paper reports the results of an experiment to evaluate a virtual acoustic space through the performance, interview, and audio analysis of the performance of a solo singer. Simulations of the same performance space using synthesized RIRs and measured RIRs were compared. In general, singers who took part in the trial could distinguish between the two simulations and rated the measured RIR simulation more highly in terms of warmth and reverberance.
Convention Paper 8380 (Purchase now)

P11-3 Enhancing the Configuration and Design of Sound Systems through SimulationFrederick Otten, Richard Foss, Rhodes University - Grahamstown, South Africa
Audio Engineers are required to design and deploy large multichannel sound systems that meet a set of requirements and use networking technologies such as Firewire and Ethernet. Bandwidth utilization and latency need to be considered. Network Simulation can be used to accurately model a network and return such information. This paper discusses a software system that has been developed to create a simulation of a network using the AES-X170 protocol for command and control. This system shows information about bandwidth and latency and is able to detect problems with parameter relationships. It also provides the ability to perform offline editing. These features significantly enhance the audio engineer’s ability to effectively design, configure, and evaluate their sound systems.
Convention Paper 8381 (Purchase now)

P11-4 What’s Wrong with Scattering Theory?Ian M. Dash, Fergus R. Fricke, University of Sydney - Sydney, NSW, Australia
The theory of long wave scattering from the side of a cylinder originated with Rayleigh and was extended to a general solution by Morse. Both solutions are based on an angular harmonic series expansion. This model is conceptually flawed. A number of physical paradoxes inherent in the model are outlined and discussed.
Convention Paper 8382 (Purchase now)

P11-5 New Proposals for the Calibration of Sound in Cinema RoomsPhilip Newell, Acoustics Consultant - Moaña, Spain; Keith Holland, ISVR, University of Southampton - Southampton, UK; Julius Newell, Electroacoustics Engineer - Lisbon, Portugal; Branko Neskov, Loudness Films - Lisbon, Portugal
The current practices for calibrating cinema rooms date back to the early 1970s. Much has been learned since then about the perception of sound, and measurement techniques have advanced greatly. Evidence has been growing that the present degree of room-to-room compatibility leaves much to be desired, and complaints about loudness and intelligibility problems persist. This paper looks at reassessing the whole process of the loudspeaker and room calibration from a modern perspective.
Convention Paper 8383 (Purchase now)

P11-6 Some Preliminary Comparisons between the Diffusion Equation Model and Room-Acoustic Rendering Equation in Complex ScenariosJuan M. Navarro, San Antonio’s Catholic University of Murcia - Guadalupe, Spain; Jose Escolano, University of Jaén - Linares, Spain; Jose J. López, Universidad Politecnica de Valencia - Valencia, Spain
Recently, a model named acoustic radiative transfer equation has been proposed as a general theory to expand geometrical room acoustic modeling algorithms. This room acoustic modeling technique establishes the basis of two recently proposed algorithms, the acoustic diffusion equation model and the room acoustic rendering equation. This paper presents some comparisons of room-acoustic parameters in-situ measurements with prediction values from both methods in a real complex shape room in order to clarify advantages and limitations of both methods. Moreover, the memory requirements and computation time have been evaluated.
Convention Paper 8384 (Purchase now)

P11-7 Spatial Room Impulse Responses with a Hybrid Modeling MethodAlex Southern, Samuel Siltanen, Lauri Savioja, Aalto University - Aalto, Finland
The synthesis of an arbitrary enclosure room impulse response (RIR) may be performed using acoustic modeling. A number of acoustic modeling methods have been proposed previously each with their own advantages and limitations. This paper is concerned with mixing the RIRs from different modeling methods to synthesize a hybrid RIR. Low frequencies are modeled using the finite difference time domain method (FDTD), high frequencies are treated with geometric methods. A practical implementation for forming a hybrid RIR is discussed and further demonstrated in the context of a 2nd order B-Format spatial encode of the modeled sound field. The paper discusses the considerations and limitations of forming such hybrid RIRs using wave-based and geometric-based methods.
Convention Paper 8385 (Purchase now)

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