The Experts below are selected from a list of 624 Experts worldwide ranked by ideXlab platform
Adam J. Hill - One of the best experts on this subject based on the ideXlab platform.
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Enhanced Wide-Area Low-Frequency Sound Reproduction in Cinemas: Effective and Practical Alternatives to Current Sub-Optimal Calibration Strategies
2015Co-Authors: Adam J. Hill, Malcolm J. Hawksford, Philip NewellAbstract:This paper explores strategies for achieving accurate wide-area low-frequency sound reproduction in cinemas. Current standards for B-Chain calibration call for single channel low-frequency equalization aided by either single-point or spatially-averaged response measurements, an approach only applicable to a reasonably spatially invariant lowfrequency response. A holistic approach to low-frequency coverage optimization is presented exploiting Subwoofer arrays, their positioning and multi-point signal processing. Acoustic-field examples are presented using finitedifference time-domain (FDTD) modeling software that expose a potential for superior wide-area signal reconstruction over that achieved using the current standards and recommendations.
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Low-Frequency Temporal Accuracy of Small-Room Sound Reproduction
Journal of The Audio Engineering Society, 2012Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:Small-room sound reproduction is strongly affected by room-modes in the low-frequency band. While the spectral impact of room-modes is well understood, there is less information on how modes degrade the spatiotemporal response of a sound reproduction system. This topic is investigated using a bespoke finite-difference time-domain (FDTD) simulation toolbox to virtually test common Subwoofer configurations using tone bursts to judge waveform fidelity over a wide listening area. Temporal accuracy is compared to the steady-state frequency response to determine any link between the two domains. The simulated results are compared to practical measurements for validation.
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Practical applications of chameleon Subwoofer arrays
Journal of The Audio Engineering Society, 2012Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:Spatiotemporal variations of the low-frequency response in a closed-space are predominantly caused by roommodes. Chameleon Subwoofer arrays (CSA) were developed to minimize this variance over a listening area using multiple independently-controllable source components and calibrated with one-time measurements. Although CSAs are ideally implemented using hybrid (multiple source component) Subwoofers, they can alternatively be realized using conventional Subwoofers. This capability is exploited in this work where various CSA configurations are tested using commercially-available Subwoofers in a small-sized listening room. Spectral and temporal evaluation is performed using tone-burst and maximum length sequence (MLS) measurements. The systems are implemented with practicality in mind, keeping the number of Subwoofers and calibration measurements to a minimum while maintaining correction benefits.
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Chameleon Subwoofer arrays in live sound
2011Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:A high quality sound system should provide consistent coverage over the entire audience area while at the same time keep the sound pressure level (SPL) on stage to a minimum in order to provide musicians, technicians and production staff with a reasonable working environment. These requirements have predominantly been met with recent advancements in line array technology, where horizontal coverage patterns of 90° or 120° a re easily achievable, minimizing sound wraparound to the stage. Coverage patterns in the Subwoofer operating range (generally below 100 Hz), however, are more difficult to control using simple one size fits all system configurations. Historically, industry-standard Subwoofers have operated as roughly omnidirectional sources, radiating energy equally in all directions. In recent years, a handful of companies have introduced cardioid or supercardioid pattern Subwoofers which can help to limit low frequency energy on stage, depending on the system configuration. In addition to this, system technicians have long used the technique of rotating every other or every third Subwoofer in vertical stacks 180° to achieve an approximate cardioid radiation pattern. Conventional Subwoofer systems suffer from a number of constraints, which can differ from venue to venue including placement issues, rigging capabilities, sightlines, truck space and, of course, budget. These drawbacks, which will be discussed in the following section, can severely diminish a system’s capability to meet the low-frequency coverage and rejection criteria
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Individualized low-frequency response manipulation for multiple listeners using chameleon Subwoofer arrays
2011 3rd Computer Science and Electronic Engineering Conference (CEEC), 2011Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:Low-frequency acoustical responses are naturally position dependent across wide listening areas. This is predominantly due to room modes in small, closed spaces. Numerous methodologies have been proposed targeting room mode compensation to give an objectively even response across all listening locations. These techniques cannot guarantee, however, that every listener receives an equally pleasing subjective response. Chameleon Subwoofer arrays (CSA) were originally developed to minimize low-frequency spatiotemporal variations by addressing frequency response errors at multiple listening locations using a Subwoofer system consisting of multiple degrees of freedom. The CSA system can alternatively be utilized to control listening locations independently, allowing each listener to adjust their localized low-frequency response to their liking. This alternate CSA implementation is evaluated using a bespoke finite-difference time-domain (FDTD) algorithm for small home theater applications.
Takanobu Nishiura - One of the best experts on this subject based on the ideXlab platform.
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acoustic space sharing based on bass tempo synchronization with parametric loudspeakers and Subwoofer
IEEE Global Conference on Consumer Electronics, 2019Co-Authors: Naoto Shimada, Masato Nakayama, Takanobu NishiuraAbstract:A parametric loudspeaker can reproduce acoustic sound with sharper directivity by using ultrasonic waves. An acoustic space-sharing system with parametric loudspeakers was recently proposed for daily sports and exercise such as dance or fitness. However, the sound quality with this system deteriorates because it is difficult to reproduce low-frequency sound with the parametric loudspeakers. We propose an acoustic space-sharing system based on bass tempo synchronization with parametric loudspeakers and a Subwoofer. From experiment results, we confirmed the effectiveness of the proposed system.
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GCCE - Acoustic Space-Sharing Based on Bass Tempo Synchronization with Parametric Loudspeakers and Subwoofer
2019 IEEE 8th Global Conference on Consumer Electronics (GCCE), 2019Co-Authors: Naoto Shimada, Masato Nakayama, Takanobu NishiuraAbstract:A parametric loudspeaker can reproduce acoustic sound with sharper directivity by using ultrasonic waves. An acoustic space-sharing system with parametric loudspeakers was recently proposed for daily sports and exercise such as dance or fitness. However, the sound quality with this system deteriorates because it is difficult to reproduce low-frequency sound with the parametric loudspeakers. We propose an acoustic space-sharing system based on bass tempo synchronization with parametric loudspeakers and a Subwoofer. From experiment results, we confirmed the effectiveness of the proposed system.
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three dimensional acoustic sound field reproduction based on hybrid combination of multiple parametric loudspeakers and electrodynamic Subwoofer
Applied Acoustics, 2012Co-Authors: Yutaro Sugibayashi, Sota Kurimoto, Daisuke Ikefuji, Masanori Morise, Takanobu NishiuraAbstract:Auditory Mixed Reality (MR) systems that reproduce Three-Dimensional (3-D) acoustic sound fields have recently become a research focus because the combination of visual and auditory MR systems can achieve a greater sense of presence than conventional visual MR systems. General auditory MR systems usually use a headphone-based system with a Head-Related Transfer Function (HRTF), which is a major system for reproducing 3-D acoustic sound fields. However, the localization accuracy of sound images with a HRTF depends on the individual. On the other hand, we have already proposed a system for reproducing a 3-D acoustic sound field with parametric loudspeakers instead of headphones. The 3-D acoustic sound field reproduced by this system has achieved a highly accurate localization of sound images. However, one problem is that it is difficult to reproduce lower frequency sounds using parametric loudspeakers, which causes a poorer sound quality. We tried to accomplish a greater sense of presence for 3-D acoustic sound fields based on a hybrid combination of an electrodynamic Subwoofer and the parametric loudspeakers by improving the sound quality. Sound images were formed at the target location using the parametric loudspeakers, and a lower frequency sound was compensated for by using the electrodynamic Subwoofer. Subjective evaluation experiments were conducted to verify the effectiveness of the proposed system. We confirmed the improved sound quality while maintaining a higher accuracy of sound image localization by using the proposed system. We also confirmed the optimum parameters of the proposed system to achieve a greater sense of presence.
Malcolm O. Hawksford - One of the best experts on this subject based on the ideXlab platform.
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Subwoofer Positioning, Orientation, and Calibration for Large-Scale Sound Reinforcement
Journal of The Audio Engineering Society, 2010Co-Authors: Adam J. Hill, Malcolm O. Hawksford, Adam P. Rosenthal, Gary GandAbstract:It is often difficult to achieve even coverage at low-frequencies across a large audience area. To complicate matters, it is desirable to have tight control of the low-frequency levels on the stage. This is generally dealt with by using cardioid Subwoofers. While this helps control the stage area, the audience area receives no clear benefit. This paper investigates how careful positioning, orientation and calibration of a multiple Subwoofer system can provide enhanced low-frequency coverage, both in the audience area and on the stage. The effects of placement underneath, on top of and in front of the stage are investigated as well as the performance of systems consisting of both flown and ground-based Subwoofers.
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Chameleon Subwoofer Arrays—Generalized Theory of Vectored Sources in a Closed Acoustic Space
Journal of The Audio Engineering Society, 2010Co-Authors: Adam J. Hill, Malcolm O. HawksfordAbstract:An equalization model is presented that seeks optimal solutions to wide area low-frequency sound reproduction in closed acoustic spaces. The methodology improves upon conventional wisdom by incorporating a generalized Subwoofer array where individual frequency dependent loudspeaker polar responses are described by complex spherical harmonic frequency dependent functions. Multi-point system identification is performed using 3dimensional finite-difference time-domain simulation with optimization applied to seek global equalization represented by a set of orthogonal transfer functions applied to each spherical harmonic of each Subwoofer within the array. The system is evaluated within a 3-dimensional virtual acoustic space using both time and frequency domain metrics.
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chameleon Subwoofer arrays generalized theory of vectored sources in a closed acoustic space
Journal of The Audio Engineering Society, 2010Co-Authors: Adam J. Hill, Malcolm O. HawksfordAbstract:An equalization model is presented that seeks optimal solutions to wide area low-frequency sound reproduction in closed acoustic spaces. The methodology improves upon conventional wisdom by incorporating a generalized Subwoofer array where individual frequency dependent loudspeaker polar responses are described by complex spherical harmonic frequency dependent functions. Multi-point system identification is performed using 3dimensional finite-difference time-domain simulation with optimization applied to seek global equalization represented by a set of orthogonal transfer functions applied to each spherical harmonic of each Subwoofer within the array. The system is evaluated within a 3-dimensional virtual acoustic space using both time and frequency domain metrics.
Giannis Stamatakis - One of the best experts on this subject based on the ideXlab platform.
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small sized Subwoofer system implementation and measurement
Audio Mostly Conference, 2012Co-Authors: Theodore Altanis, Fotios Kontomichos, John Mourjopoulos, Giannis StamatakisAbstract:In this paper an implementation for a small-sized Subwoofer system is proposed, utilizing three 4-inch drivers. The low frequency reproduction approach adopted here is based on narrow bandwidth loudspeaker design with high quality factors. The desired resonance frequency of each loudspeaker is obtained by increasing the cone mass, in order to minimize the volume of each enclosure.
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Audio Mostly Conference - Small-sized Subwoofer system implementation and measurement
Proceedings of the 7th Audio Mostly Conference on A Conference on Interaction with Sound - AM '12, 2012Co-Authors: Theodore Altanis, Fotios Kontomichos, John Mourjopoulos, Giannis StamatakisAbstract:In this paper an implementation for a small-sized Subwoofer system is proposed, utilizing three 4-inch drivers. The low frequency reproduction approach adopted here is based on narrow bandwidth loudspeaker design with high quality factors. The desired resonance frequency of each loudspeaker is obtained by increasing the cone mass, in order to minimize the volume of each enclosure.
Malcolm J. Hawksford - One of the best experts on this subject based on the ideXlab platform.
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Enhanced Wide-Area Low-Frequency Sound Reproduction in Cinemas: Effective and Practical Alternatives to Current Sub-Optimal Calibration Strategies
2015Co-Authors: Adam J. Hill, Malcolm J. Hawksford, Philip NewellAbstract:This paper explores strategies for achieving accurate wide-area low-frequency sound reproduction in cinemas. Current standards for B-Chain calibration call for single channel low-frequency equalization aided by either single-point or spatially-averaged response measurements, an approach only applicable to a reasonably spatially invariant lowfrequency response. A holistic approach to low-frequency coverage optimization is presented exploiting Subwoofer arrays, their positioning and multi-point signal processing. Acoustic-field examples are presented using finitedifference time-domain (FDTD) modeling software that expose a potential for superior wide-area signal reconstruction over that achieved using the current standards and recommendations.
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Low-Frequency Temporal Accuracy of Small-Room Sound Reproduction
Journal of The Audio Engineering Society, 2012Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:Small-room sound reproduction is strongly affected by room-modes in the low-frequency band. While the spectral impact of room-modes is well understood, there is less information on how modes degrade the spatiotemporal response of a sound reproduction system. This topic is investigated using a bespoke finite-difference time-domain (FDTD) simulation toolbox to virtually test common Subwoofer configurations using tone bursts to judge waveform fidelity over a wide listening area. Temporal accuracy is compared to the steady-state frequency response to determine any link between the two domains. The simulated results are compared to practical measurements for validation.
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Practical applications of chameleon Subwoofer arrays
Journal of The Audio Engineering Society, 2012Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:Spatiotemporal variations of the low-frequency response in a closed-space are predominantly caused by roommodes. Chameleon Subwoofer arrays (CSA) were developed to minimize this variance over a listening area using multiple independently-controllable source components and calibrated with one-time measurements. Although CSAs are ideally implemented using hybrid (multiple source component) Subwoofers, they can alternatively be realized using conventional Subwoofers. This capability is exploited in this work where various CSA configurations are tested using commercially-available Subwoofers in a small-sized listening room. Spectral and temporal evaluation is performed using tone-burst and maximum length sequence (MLS) measurements. The systems are implemented with practicality in mind, keeping the number of Subwoofers and calibration measurements to a minimum while maintaining correction benefits.
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Chameleon Subwoofer arrays in live sound
2011Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:A high quality sound system should provide consistent coverage over the entire audience area while at the same time keep the sound pressure level (SPL) on stage to a minimum in order to provide musicians, technicians and production staff with a reasonable working environment. These requirements have predominantly been met with recent advancements in line array technology, where horizontal coverage patterns of 90° or 120° a re easily achievable, minimizing sound wraparound to the stage. Coverage patterns in the Subwoofer operating range (generally below 100 Hz), however, are more difficult to control using simple one size fits all system configurations. Historically, industry-standard Subwoofers have operated as roughly omnidirectional sources, radiating energy equally in all directions. In recent years, a handful of companies have introduced cardioid or supercardioid pattern Subwoofers which can help to limit low frequency energy on stage, depending on the system configuration. In addition to this, system technicians have long used the technique of rotating every other or every third Subwoofer in vertical stacks 180° to achieve an approximate cardioid radiation pattern. Conventional Subwoofer systems suffer from a number of constraints, which can differ from venue to venue including placement issues, rigging capabilities, sightlines, truck space and, of course, budget. These drawbacks, which will be discussed in the following section, can severely diminish a system’s capability to meet the low-frequency coverage and rejection criteria
-
Individualized low-frequency response manipulation for multiple listeners using chameleon Subwoofer arrays
2011 3rd Computer Science and Electronic Engineering Conference (CEEC), 2011Co-Authors: Adam J. Hill, Malcolm J. HawksfordAbstract:Low-frequency acoustical responses are naturally position dependent across wide listening areas. This is predominantly due to room modes in small, closed spaces. Numerous methodologies have been proposed targeting room mode compensation to give an objectively even response across all listening locations. These techniques cannot guarantee, however, that every listener receives an equally pleasing subjective response. Chameleon Subwoofer arrays (CSA) were originally developed to minimize low-frequency spatiotemporal variations by addressing frequency response errors at multiple listening locations using a Subwoofer system consisting of multiple degrees of freedom. The CSA system can alternatively be utilized to control listening locations independently, allowing each listener to adjust their localized low-frequency response to their liking. This alternate CSA implementation is evaluated using a bespoke finite-difference time-domain (FDTD) algorithm for small home theater applications.
