AES Los Angeles 2014
Paper Session P3
P3 - Spatial Audio: Part 2
Thursday, October 9, 2:30 pm — 6:30 pm
Clemens Par, Swiss Audec - Morges, Switzerland
P3-1 A Polygon-Based Panning Method for 3D Loudspeaker Setups—Christian Borß, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany
In this paper we introduce the “Edge Fading Amplitude Panning” (EFAP) method for 3D loudspeaker setups. Similar to other panning methods like Vector Base Amplitude Panning (VBAP), it can be used to create phantom sources between the loudspeaker positions. The proposed method features symmetric panning gains for symmetric loudspeaker setups, N-wise panning by using polygons instead of triangles, and a better behavior for large opening angles between loudspeakers while involving a computational complexity that is in the same order of magnitude as VBAP.
Convention Paper 9106
P3-2 Utilizing Contralateral ICTDs to Stabilize Lateral Imaging in 5.1 Surround Systems—Michael Tierney, New York University - New York, NY, USA; Adrian Tregonning, New York University - New York, NY, USA
In 5.1 surround sound systems the problems of lateral image instability and a non-linear lateral panning path are well known. Alternative panning techniques have been developed in an attempt to overcome these problems, but often improved spatial imaging compromises spectral integrity. This is an undesirable tradeoff in the context of music mixing and production. The current paper examines the effect of low-level inter-channel time differences (ICTDs) in contralateral channels with respect to lateral imaging. Subjective experiments evaluated localization perceptions with ICTDs of 1 ms in either the front or surround contralateral channel. This led to more accurate and predictable lateral image positioning with minimal spectral coloration. The results are used to propose a more effective 5.1 lateral panning mechanism.
Convention Paper 9107
P3-3 Investigation into the Impact of 3D Surround Systems on Envelopment—Paul Power, University of Salford - Salford, Greater Manchester, UK; Bill Davies, University of Salford - Salford, Greater Manchester, UK; Jonathan Hirst, University of Salford - Salford, Greater Manchester, UK
This investigation assessed a number of 2D and 3D surround systems focusing on the attribute “envelopment? to determine if surround systems with height significantly enhance the perception of envelopment over current 2D systems. To assess each of the systems an objective and subjective method was used. The objective method consisted of measuring the IACC (Inter-Aural Cross Correlation) of each reproduction system by reproducing three different types of sound scenes over each system. In addition, a subjective listening test was also carried out to evaluate the perceived envelopment. The objective measure showed that the introduction of height channels did lower the IACC. Further, subjective listening test results showed that there were significant differences between the height and horizontal surround systems in terms of envelopment, however this was dependent on the audio stimulus used. Finally, a correlation between the objective and subjective measures showed a strong negative correlation.
Convention Paper 9108
P3-4 An Architecture for Reverberation in High Order Ambisonics—Fernando Lopez-Lezcano, CCRMA, Stanford University - Stanford, CA, USA
This paper describes a reverberation architecture implemented within the signal chain of a periphonic HOA (High Order Ambisonics) audio stream. An HOA signal (3rd order in the example implementation) representing the dry source signal is decoded into an array of virtual sources uniformly distributed within the reverberant space being simulated. These virtual sources are convolved with independent, decorrelated impulse responses, optionally tailored to model spatial variations of the simulated reverberation. The output of each convolver is then encoded back into High Order Ambisonics and mixed with the original Ambisonics dry signal. The result is a convolution reverberation engine with a HOA input that outputs HOA and maintains the spatial characteristics of the input signal.
Convention Paper 9109
P3-5 Spatial Calibration of Surround Sound Systems including Listener Position Estimation—Guangji Shi, DTS, Inc. - Los Gatos, CA, USA; Martin Walsh, DTS Inc. - Los Gatos, CA, USA; Edward Stein, DTS, Inc. - Los Gatos, CA, USA
While most modern surround sound formats specify ideal loudspeaker placement, it is often impractical to comply with these specifications in most homes. In this paper we propose a simplified approach to spatial calibration for incorrectly set up surround sound systems. The proposed system utilizes a microphone array embedded into a component of the reproduction system whose location is predictable, such as a sound bar or a front center speaker. In addition to estimating loudspeaker positions, the proposed system is able to estimate a listener’s position using voice input and calibrate the surround sound system utilizing the estimated listener position. Tests conducted in a typical living room setup show that the proposed system is able to improve the listening experience on such compromised systems with only simple user interactions such as voice commands.
Convention Paper 9110
P3-6 Comparison of Pressure-Matching and Mode-Matching Beamforming for Methods for Circular Loudspeaker Arrays—Filippo Maria Fazi, University of Southampton - Southampton, Hampshire, UK; Mincheol Shin, ISVR, University of Southampton - Southampton, Hampshire, UK; Ferdinando Olivieri, University of Southampton - Southampton, Hampshire, UK; Simone Fontana, Huawei European Research Center - Munich, Germany; Yue Lang, Huawei European Research Center - Munich, Germany
Pressure-matching and mode-matching are two well-known strategies used for the computation of beamforming digital filters for microphone and loudspeaker arrays. A theoretical comparison is presented of these two methods when these are applied to a circular loudspeaker array mounted on a rigid cylinder. The pressure-matching method is used to generate the desired acoustic pressure at a number of control points arranged in the far field of a circular loudspeaker array, while in the case of mode-matching an attempt is made to minimize the squared error between the Fourier coefficients that represent the reproduced and target radiation pattern of the array. It is shown that, in the case under consideration, the two strategies are identical if the effect of spatial aliasing is negligible.
Convention Paper 9111
P3-7 MIAP: Manifold-Interface Amplitude Panning in Max/MSP and Pure Data—Zachary Seldess, Sonic Arts R&D, UC San Diego - San Diego, CA, USA
This paper discusses MIAP (Manifold-Interface Amplitude Panning), a new freely available implementation of Meyer Sound’s SpaceMap abstract spatialization software via a collection of C externals for Max/MSP and Pure Data. SpaceMap’s technical and conceptual innovations are discussed and placed within the larger context of widely available codified spatialization algorithms and approaches such as Vector-base amplitude panning. An examination of the new implementation is made along with discussion of added features resulting from the translation.
Convention Paper 9112
P3-8 Aurally Aided Visual Search Performance Comparing Virtual Audio Systems—Camilla H. Larsen, Aalborg University - Aalborg, Denmark; David S. Lauritsen, Aalborg University - Aalborg, Denmark; Jacob J. Larsen, Aalborg University - Aalborg, Denmark; Marc Pilgaard, Aalborg University - Aalborg, Denmark; Jacob B. Madsen, Aalborg University - Aalborg, Denmark; Rasmus Stenholt, Aalborg University - Aalborg, Denmark
Due to increased computational power reproducing binaural hearing in real-time applications, through usage of head-related transfer functions (HRTFs), is now possible. This paper addresses the differences in aurally-aided visual search performance between an HRTF enhanced audio system (3D) and an amplitude panning audio system (panning) in a virtual environment. We present a performance study involving 33 participants locating aurally-aided visual targets placed at fixed positions, under different audio conditions. A varying amount of visual distractors were present, represented as black circles with white dots. The results indicate that 3D audio yields faster search latencies than panning audio, especially with larger amounts of distractors. The applications of this research could fit virtual environments such as video games or virtual simulations.
Convention Paper 9150