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P7 - Multichannel Sound -2
Saturday, October 8, 1:00 pm — 4:00 pm
Chair: Richard Duda, University of California at Davis - Davis, CA, USA
P7-1 An Approach for Multichannel Recording and Reproduction of Sound Source Directivity—Roland Jacques, Technical University Ilmenau - Ilmenau, Germany; Bernhard Albrecht, Technical University Ilmenau - Ilmenau, Germany; Frank Melchior, Fraunhofer Institute for Digital Media Technology - Ilmenau, Germany; Diemer de Vries, Delft University of Technology - Delft, The Netherlands
Current holophonic sound systems allow the creation and free positioning of virtual sound sources. But only few systems incorporate the directivity characteristics of natural sources; virtual sources are mostly monopoles. Especially in the case of auditory scenes with a high degree of freedom for source and listener positioning, the reproduction of directivities is desirable. This paper presents an approach for the efficient multichannel capturing of source directivities, as well as a suitable reproduction technique that creates an extensive sound field approximating the directional radiation of the real source. The performance of this system, which is based on wave field synthesis, has been examined by means of dedicated measurements and listening tests from recordings of brass instruments.
Convention Paper 6554 (Purchase now)
P7-2 Artificial Reverberation Algorithm to Control Distance and Direction of Sound Source for Multichannel Audio System—Jeong-Hun Seo, Hwan Shim, Seoul National University - Seoul, Korea; Jae-Hyoun Yoo, Electronics and Telecommunications Research Institute (ETRI) - Daejon, Korea; Koeng-Mo Sung, Seoul National University - Seoul, Korea
A multichannel artificial reverberation algorithm to control perceived direction and distance is described in this paper. In conventional algorithms using IIR filters, reverberation time is the only parameter to be controlled. Moreover, since the convolution-based conventional algorithms apply only same impulse responses, but did not consider sound localization, it was not realistic enough. The new algorithm proposed in this paper utilizes early reflections segmented according to the azimuth from which direct sound comes and controls perceived direction by panning the direct sound, and controls perceived distance by adjusting the Energy Decay Curve (EDC) of reverberation and gain of the direct sound. In addition, the algorithm enhances Listener Envelopment(LEV) to make late reverberation incoherent among channels.
Convention Paper 6555 (Purchase now)
P7-3 Surround Recording of Music: Problems and Solutions—Joerg Wuttke, SCHOEPS GmbH - Karlsruhe (Durlach), Germany
How can we make surround recording for pure audio applications more successful? Musical content and good sound (among other concerns) are as important in surround as they are in 2-channel stereo. But the manufacturers of home playback equipment and the producers of program material have not yet fulfilled all the possibilities. Surround, if it is to justify its higher costs, must offer both localization and a sense of spaciousness throughout an enlarged listening area. Success will therefore depend on the prevalence of recording methods that extract maximum benefit from the center channel. Various possibilities exist for surround microphone arrangements; several different methods for 5.0 pickup will be described, along with the issues of crosstalk and "stereo down-mix" compatibility.
Convention Paper 6556 (Purchase now)
P7-4 Motion-Tracked Binaural Sound for Personal Music Players—V. Ralph Algazi, Robert Dalton, Jr., Richard Duda, Dennis M. Thompson, University of California at Davis - Davis, CA, USA
Motion-tracked binaural or MTB recording enhances headphone-based spatial sound reproduction by capturing and exploiting localization cues that result from voluntary head motion. For music reproduction, the sound field can be stabilized for any arbitrary head rotation by using sixteen microphones to sample the space around the head and by employing the signal from a head tracker to interpolate between these channels. MTB’s use of headphones makes it particularly suitable for portable music players. However, the technique must be modified to meet the special needs of this application. Methods are described for (a) converting legacy recordings to MTB format, (b) reducing the number of channels from 16 to 2.5, and (c) processing the head-tracker signal to extract head motion from the combination of head and torso motion.
Convention Paper 6557 (Purchase now)
P7-5 Subjective Consumer Evaluation of Multichannel Audio Codecs—Jim Barbour, Swinburne University of Technology - Melbourne, Australia
Are normal listeners able to identify any significant differences between multichannel audio codecs when listening to commercial music releases on good quality, consumer audio equipment? Audio professionals have often questioned whether consumers are able to hear the difference between high density, uncompressed multichannel formats, and lower data-rate delivery formats. In this study, formal subjective listening tests were conducted according to the ITU-R BS.1534 (MUSHRA) recommendation to evaluate consumer perception of popular 5.1 surround sound formats, namely Dolby AC-3, DTS, WMA Pro and mp3surround. Results suggest there is a threshold data-rate below which consumers are able to hear audible differences. Experimental design, methodology, and results will be presented and discussed.
Convention Paper 6558 (Purchase now)
P7-6 Advanced Multichannel Audio System for Reproducing a Live Sound Field with Ultimate Sensation of Presence—Kimio Hamasaki, Hiroyuki Okubo, Toshiyuki Nishiguchi, Yasushige Nakayama, Reiko Okumura, Masakazu Iwki, NHK Science & Technical Research Laboratories - Tokyo, Japan
An advanced multichannel audio system for reproducing a live sound field with ultimate sensation of presence has been studied for reproducing the sound field without any restrictions on the listening points. This system also aims to give audiences the best natural impression of presence and reality according to their listening point and to be applicable to live broadcasting. This paper introduces the experimental sound system and describes in detail the recording techniques and latest subjective evaluation experiments to evaluate the appropriateness of necessary conditions of the new sound system. The paper also discusses the advantages of the new sound system regarding the impression of presence and interactivity compared with conventional multichannel audio systems.
Convention Paper 6559 (Purchase now)