120th AES Convention - Paris, France - Dates: Saturday May 20 - Tuesday May 23, 2006 - Porte de Versailles

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AES Paris 2006

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Last Updated: 20060403, mei

P7 - Multichannel Sound, Part 1

Sunday, May 21, 08:40 — 12:20

Chair: Jan Berg, Luleå University of Technology - Luleå, Sweden

P7-1 Effectiveness of Height Information for Reproducing the Presence and Reality in the Multichannel Audio SystemKimio Hamasaki, Toshiyuki Nishiguchi, NHK Science & Technical Research Laboratories - Tokyo, Japan; Koichiro Hiyama, NHK Kumamoto Station - Kumamoto, Japan; Reiko Okumura, NHK Science & Technical Research Laboratories - Tokyo, Japan
A 22.2 multichannel sound system was developed that adapts to an ultrahigh-definition video system with 4000 scanning lines. The sound system consists of loudspeakers with three layers: an upper layer with nine channels, a middle layer with ten channels, and a lower layer with three channels and two channels for low frequency effects. This system has new features of three-dimensional sound reproduction. Subjective evaluation by the semantic differential (SD) method are presented to assess the importance of height information for a sound system using several stimuli in a 22.2 multichannel audio system with Super Hi-Vision and a high-definition television. Furthermore, the actual effectiveness of height information and some practical suggestions for aesthetic mixing of three-dimensional audio is also presented.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at 08:40
Convention Paper 6679 (Purchase now)

P7-2 Multichannel Signal Processing for Microphone ArraysPaolo Martignon, University of Parma - Parma, Italy
Microphone arrays are employed to make measurements or recordings taking into account the spatial properties of sound. Here the attention is focused on planar arrays oriented to acoustic mapping, which have a particular interest in industrial and environmental acoustics, although musical and audio applications are directly involved. A beam-forming theory overview is proposed, with a light study of array spatial resolution theory that holds a physical base, which no algorithm can deny. Then, a new algorithm, based on Kirkeby multichannel inversion, is proposed. Comparison between multichannel inversion, and beam forming are made through simulations, with good news for the new method.

Presentation is scheduled to begin at 09:00
Convention Paper 6680 (Purchase now)

P7-3 Miniature Microphone Arrays for Multichannel RecordingJuha Backman, Nokia Corporation - Espoo, Finland
This paper describes a method of using a dense array of miniature microphones (e.g., MEMS or miniature electret) to yield precise one-point multichannel gradient microphones. The signals obtained from individual microphones in the array are used to obtain an estimate for the zero, first-, and second-order components of the gradient of the sound field at the center of the array. (Higher orders of the gradient tend to be too noisy for actual sound recording purposes.) These can be used to form stereo or multichannel signals with adjustable polar patterns for recording purposes.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at09:20
Convention Paper 6681 (Purchase now)

P7-4 Benefits of Distance Correction for Multichannel MicrophonesThomas Görne, Detmold University of Music - Detmold, Germany
Subjective assessment of stereophonic or multichannel microphone techniques often suffers from differences in the diffuse field sensitivities of various arrays. Diffuse field behavior of single rotation-symmetrical microphones at lateral direct sound incidence can be derived from the polar equations of ideal first-order gradient transducers. This simple model is used to estimate distance correction factors for symmetrical two-dimensional arrays as well as for MS pairs. The benefits of corrected stereo setups are also investigated.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at 09:40
Convention Paper 6682 (Purchase now)

P7-5 Virtual Source Location Information-Based Matrix Decoding SystemHan-gil Moon, Manish Arora, Samsung Electronics Co. Ltd. - Suwon, Gyeonggi-Do, Korea
In this paper a new matrix decoding system using vector-based Virtual Source Location Information (VSLI) is proposed as one alternative to the conventional Dolby Pro logic II/IIx system for reconstructing multichannel output signal from matrix encoded 2-channel signals, Lt/Rt. This new matrix decoding system is composed of a passive decoding part and an active part. The passive part makes crude multichannel signals using a linear combination of the two encoded signals(Lt/Rt), and the active part enhances each channel regarding the virtual source, which is emergent in each inter channel. The virtual sources between channels are estimated by the inverse constant power panning law.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at 10:00
Convention Paper 6683 (Purchase now)

P7-6 Relating Auditory Attributes of Multichannel Sound to Preference and to Physical ParametersSylvain Choisel, Aalborg University - Aalborg, Denmark, Bang & Olufsen A/S, Struer, Denmark; Florian Wickelmaier, Aalborg University - Aalborg, Denmark
Sound reproduced by multichannel systems is affected by many factors giving rise to various sensations, or auditory attributes. Relating specific attributes to overall preference and to physical measures of the sound field provides valuable information for a better understanding of the parameters playing a role in sound quality evaluation. Eight selected attributes are quantified by a panel of 39 listeners using paired-comparison judgments and probabilistic choice models, and related to overall preference. A multiple-regression model predicts preference well, and some similarities are observed within and between musical program materials, allowing for a careful generalization regarding the perception of spatial audio reproduction. Finally, a set of objective measures is derived from analysis of the sound field at the listening position in an attempt to predict the auditory attributes.

Presentation is scheduled to begin aat 10:20
Convention Paper 6684 (Purchase now)

P7-7 Quality Degradation Effects Caused by Limiting the Bandwidth of Standard Surround Sound Channels and Hierarchically Encoded MSBTF Channels: A Comparative StudyYu Jiao, Slawomir Zielinski, Francis Rumsey, University of Surrey - Guildford, Surrey, UK
Limiting the bandwidth of multichannel audio can be used as an effective method of trading-off audio quality with broadcasting costs. In this paper subjective effects of two controlled high-frequency limitation methods on multichannel audio quality were studied with formal listening tests. The first method was based on limiting the bandwidth of standard surround sound channels (Rec. ITU-R BS. 775-1); the second involved limiting the bandwidth of the hierarchically encoded MSBTF channels. The results are compared and discussed. In this experiment, the low frequency effect (LFE) channel was omitted.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at 10:40
Convention Paper 6685 (Purchase now)

P7-8 Initial Developments of an Objective Method for the Prediction of Basic Audio Quality for Surround Audio RecordingsSunish George, Slawomir Zielinski, Francis Rumsey, University of Surrey - Guildford, Surrey, UK
This paper describes the development of the objective method for the prediction of the Basic Audio Quality (BAQ) of band-limited or down-mixed surround audio recordings. A number of physical parameters, including interaural cross-correlation coefficients and spectral descriptors, were extracted from the recordings and used in a linear regression model to predict BAQ scores obtained from listening tests. The results showed a high correlation between the predicted scores and those obtained from the listening test, with the average error of prediction being smaller than 10 percent. Although the method was originally developed for 5-channel surround recordings, after some modifications it can be upgraded to any number of audio channels.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at 11:00
Convention Paper 6686 (Purchase now)

P7-9 Listener Opinions of Novel Spatial Audio ScenesKathryn Beresford, Francis Rumsey, Slawomir Zielinski, University of Surrey - Guildford, Surrey, UK
Listener opinions for alternative approaches to recording multichannel classical music were investigated, particularly considering alternatives to the traditional approach. Recordings were made with pre-existing microphone arrays but alternative arrangements of musicians. These were used in a listening test to assess different attributes (timbral balance, envelopment, locatedness, etc.). From the results it was noted that naïve and trained listeners assessed the recordings in different ways. Through factor analysis, two components were identified to represent these assessments—creativity and conventionality. The naïve listeners indicated that purchasability was closely related to creativity whereas for the trained listeners, conventionality was an indicator of purchasability. A method for predicting purchasability was developed, which may aid future work in the area.

Presentation is scheduled to begin at 11:20
Convention Paper 6687 (Purchase now)

P7-10 Low Frequency Sound Field Enhancement System for Rectangular Rooms Using Multiple Low Frequency LoudspeakersAdrian Celestinos, Sofus Birkedal Nielsen, Aalborg University - Aalborg, Denmark
Rectangular rooms have strong influence on the low frequency performance of loudspeakers. Simulations of three different room sizes have been carried out using the finite-difference time-domain method (FDTD) in order to predict the behavior of the sound field at low frequencies. By using an enhancement system with extra loudspeakers the sound pressure level distribution along the listening area presents a significant improvement in the subwoofer frequency range. The system is simulated and implemented on the three different rooms and finally verified by measurements on the real rooms.

Presentation is scheduled to begin at 11:40
Convention Paper 6688 (Purchase now)

P7-11 Tactile Strategies and Resources for Teaching Multichannel Sound ConceptsLeslie Gaston, University of Colorado at Denver - Denver, CO, USA
Several university audio programs now incorporate multichannel, or surround sound, into their curricula. In order to supplement these courses and lectures many opportunities exist to incorporate hands-on demonstrations of concepts used for microphone techniques, mixing, monitoring, and delivery. This paper will give suggestions for different tactile strategies that can be used to illustrate concepts in multichannel audio, as well as other resources that may be utilized when doing preparation and research for teaching classes. Suggestions for homework and research topics for students will also be provided, along with recommended equipment needs.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at 12:00
Convention Paper 6689 (Purchase now)

  (C) 2006, Audio Engineering Society, Inc.