AES New York 2015
Paper Session P19
P19 - Spatial Audio—Part 3
Sunday, November 1, 9:00 am — 12:30 pm (Room 1A08)
Chair:
Jean-Marc Jot, DTS, Inc. - Los Gatos, CA, USA
P19-1 Estimating the Total Sound Power of Loudspeakers—Adrian Celestinos, Samsung Research America - Valencia, CA, USA; Allan Devantier, Samsung Research America - Valencia, CA, USA; Andri Bezzola, Samsung Research America - Valencia, CA USA; Ritesh Banka, Samsung Research America - Valencia, CA USA; Pascal Brunet, Samsung Research America - Valencia, CA USA; Audio Group - Digital Media Solutions
When designing loudspeakers, a number of parameters have to be known. The total radiated sound power is one of these measures. Typically performed in anechoic conditions a large number of measurements are needed for this estimation. It is of interest to know how accurate this estimation is related to the actual radiated power. Two coherent point sound sources separated by 30 cm are simulated in three scenarios. The sound pressure is calculated over discrete points at a distance around a sphere covering the two point sources. The error between estimated and analytical sound power solution is computed. A number of different microphone arrangements are tested. Results suggest that spatial distribution over the sphere and the number of measurements is critical.
Convention Paper 9463 (Purchase now)
P19-2 Loudness Matching Multichannel Audio Program Material with Listeners and Predictive Models—Jon Francombe, University of Surrey - Guildford, Surrey, UK; Tim Brookes, University of Surrey - Guildford, Surrey, UK; Russell Mason, University of Surrey - Guildford, Surrey, UK; Frank Melchior, BBC Research and Development - Salford, UK
Loudness measurements are often necessary in psychoacoustic research and legally required in broadcasting. However, existing loudness models have not been widely tested with new multichannel audio systems. A trained listening panel used the method of adjustment to balance the loudness of eight reproduction methods: low-quality mono, mono, stereo, 5-channel, 9-channel, 22-channel, ambisonic cuboid, and headphones. Seven program items were used, including music, sport, and a film soundtrack. The results were used to test loudness models including simple energy-based metrics, variants of ITU-R BS.1770, and complex psychoacoustically motivated models. The mean differences between the perceptual results and model predictions were statistically insignificant for all but the simplest model. However, some weaknesses in the model predictions were highlighted.
Convention Paper 9464 (Purchase now)
P19-3 Dynamic Range and Loudness Control in MPEG-H 3D Audio—Fabian Kuech, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Michael Kratschmer, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Bernhard Neugebauer, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Michael Meier, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Frank Baumgarte, Apple Inc. - Cupertino, CA, USA
Recently the new MPEG-H 3D Audio standard has been finalized. It has been designed for delivery of next generation audio content to the user. In addition to highly efficient immersive audio transmission, MPEG-H 3D Audio allows new capabilities such as personalization and adaptation of the audio content to different use scenarios. It also provides an enhanced concept for loudness and dynamic range control (DRC) to adapt the characteristics of the audio content to the requirements of different playback scenarios and listening conditions. This paper gives a detailed overview of the loudness control and DRC functionality of MPEG-H 3D Audio. Relevant use cases are discussed to exemplify the application of the enhanced DRC and loudness management features.
Convention Paper 9465 (Purchase now)
P19-4 Implementing the Radiation Characteristics of Musical Instruments in a Psychoacoustic Sound Field Synthesis System—Tim Ziemer, University of Hamburg - Hamburg, Germany; Rolf Bader, Universität Hamburg - Hamburg, Germany
A method is introduced to measure the radiation characteristics of musical instruments and to calculate the sound field radiated to an extended listening area. This sound field is synthesized by means of a loudspeaker system to create a natural, spatial instrumental sound. All instruments are considered as complex point sources, which makes it easy to measure, analyze, and compare their radiation characteristics as well as to propagate the radiated sound to discrete listening points. The sound field at these listening points as well as the loudspeaker driving signals to synthesize them are calculated in frequency domain. This makes spatial windowing superfluous and allows for all loudspeakers to be active for any virtual source position. However, this procedure introduces synthesis errors that are compensated for the listener by implementing psychoacoustic methods. The synthesis principle works already with low-order loudspeaker systems such as discrete quadraphonic and 5.1 systems as well as with existing ambisonics and wave field synthesis setups with dozens to hundreds of loudspeakers. Aliasing frequency and synthesis precision are dependent on the number of loudspeakers and the extent of the listening area, not on the distance of adjacent loudspeakers. A listening test demonstrates that the approach creates a listening experience comparable with mono and stereo concerning localization and naturalness of the sound and an increased spaciousness.
Convention Paper 9466 (Purchase now)
P19-5 New Techniques for Sound Motion and Display in a 52.1 Surround Sound Hall—Tomás Henriques, SUNY College at Buffalo - Buffalo, NY, USA
The creation of a 52.1 surround sound system is described with a focus on new strategies for sound motion and localization. Innovative artistic, technical, and research approaches to multichannel electronic music composition, spatial sound design, and sound-localization solutions for the study of auditory perception are introduced. A set of software applications is discussed to illustrate the scope of creative possibilities offered by the surround system as a singular performance and research venue.
Convention Paper 9467 (Purchase now)
P19-6 Physical Properties of Modal Beamforming in the Context of Data-Based Sound Reproduction—Nara Hahn, University of Rostock - Rostock, Germany; Sascha Spors, University of Rostock - Rostock, Germany
A sound field captured by a microphone array can be decomposed into plane waves, and auralized by means of sound field synthesis or binaural synthesis. The achievable performance is limited by the spatial resolution of the plane wave decomposition. Typically, the plane wave decomposition is performed with respect to an expansion center. If the expansion center is translated, the accuracy of the plane wave representation decreases. It is thus likely that the reproduced sound field also suffers form artifacts at off-center listening positions. The aim of this paper is to investigate the physical properties of a sound field represented as plane wave decomposition. The sound field is re-expanded with respect to different positions, and the corresponding modal spectra are investigated. This analysis successfully explains the spectral and temporal properties of spatially continuous and discrete modal beamforming.
Convention Paper 9468 (Purchase now)
P19-7 The Vertical Precedence Effect: Utilizing Delay Panning for Height Channel Mixing in 3D Audio—Adrian Tregonning, New York University - New York, NY, USA; Bryan Martin, McGill University - Montreal, QC, Canada; Centre for Interdisciplinary Research in Music Media and Technology (CIRMMT) - Montreal, QC, Canada
A strong understanding of psychoacoustic cues is necessary for effective 3D sound reproduction, and the vertical aspects of acoustics and psychoacoustics become even more important than for stereo. This study investigated vertical inter-channel time differences (ICTDs) for frontal imaging in the Auro-3D 9.1 loudspeaker configuration. It was found that vertical ICTDs had a significant effect on perceived images, indicating the operation of the precedence effect in the vertical direction. In particular, 5 ms was found to be a threshold for maximal source elevation. Above this threshold, elevation effects were less prominent but ICTDs significantly increased both phantom image width and vertical spread. The techniques established in this study can assist in the creation of effective immersive content.
Convention Paper 9469 (Purchase now)
