Directivity Patterns for Room Acoustical Measurements and Simulations

Directivity Patterns for Room Acoustical Measurements and Simulations PDF Author: Martin Pollow
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832540903
Category : Technology & Engineering
Languages : en
Pages : 192

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Book Description
The acoustics of rooms can be objectively described by the room impulse responses obtained for given transfer paths using measurement or simulation. In practice, the directionally dependent behavior of sources and receivers is often disregarded and thus assumed to be of omnidirectional type. In reality, however, these sources and receivers have specific directivity patterns, which are reported to induce audible differences. In this work a methodology to capture, analyze and process directivity patterns of sources and receivers is described. With the help of surrounding spherical microphone and loudspeaker arrays these directivity patterns are measured to be used in room acoustic applications. Room impulse responses with respect to specific directivity patterns can be realized using compact loudspeaker arrays with known directivity. Applying the results of directivity superposition to the set of measured room impulse responses, the acoustics for specific directivity patterns are found. Using a simulation of the room instead, source and receiver directivity patterns can be included in both wave based and particle based methods. The results of this work facilitate more authentic descriptions of room acoustics for specific source and receiver directivity patterns.

Directivity Patterns for Room Acoustical Measurements and Simulations

Directivity Patterns for Room Acoustical Measurements and Simulations PDF Author: Martin Pollow
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832540903
Category : Technology & Engineering
Languages : en
Pages : 192

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Book Description
The acoustics of rooms can be objectively described by the room impulse responses obtained for given transfer paths using measurement or simulation. In practice, the directionally dependent behavior of sources and receivers is often disregarded and thus assumed to be of omnidirectional type. In reality, however, these sources and receivers have specific directivity patterns, which are reported to induce audible differences. In this work a methodology to capture, analyze and process directivity patterns of sources and receivers is described. With the help of surrounding spherical microphone and loudspeaker arrays these directivity patterns are measured to be used in room acoustic applications. Room impulse responses with respect to specific directivity patterns can be realized using compact loudspeaker arrays with known directivity. Applying the results of directivity superposition to the set of measured room impulse responses, the acoustics for specific directivity patterns are found. Using a simulation of the room instead, source and receiver directivity patterns can be included in both wave based and particle based methods. The results of this work facilitate more authentic descriptions of room acoustics for specific source and receiver directivity patterns.

Measurement of Surface Reflection Properties

Measurement of Surface Reflection Properties PDF Author: Markus Müller-Trapet
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832541209
Category : Technology & Engineering
Languages : en
Pages : 220

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Book Description
In this thesis, acoustic measurement techniques related to the absorbing as well as the scattering properties of architectural surfaces are investigated. The research is divided into two parts: the first part consists of determining the most relevant causes of uncertainty for the standardized measurement methods of random-incidence absorption and scattering coefficients. A method is developed to determine the necessary minimum number of source-receiver combinations in the reverberation chamber to ensure a specified precision of the absorption or scattering coefficient. The second part of the thesis focuses on a hemispherical microphone array and signal processing steps related to the measurement of angle-dependent reflection properties. Measurements show that the array setup can be used to obtain the angle-dependent absorbing properties of samples with few source positions. With the help of array signal processing methods, the setup can also be used to determine the directional diffusion and scattering coefficient of small samples, yielding the same result as established far-field methods.

Combined Wave and Ray Based Room Acoustic Simulations of Small Rooms

Combined Wave and Ray Based Room Acoustic Simulations of Small Rooms PDF Author: Marc Aretz
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832532420
Category : Science
Languages : en
Pages : 221

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Book Description
The present thesis establishes a complete framework for the combination of finite element and classical ray based acoustic simulations in small rooms and discusses the inherent challenges and limitations including all aspects of sound generation, sound reflection and sound reception. In this context, the thesis gives detailed guidelines for the best-possible determination of all necessary input data for both simulation domains. The overall potential of the presented combined approach is assessed by conducting extensive objective and subjective comparisons of measurement and simulation results for three types of acoustically relevant small spaces (a scale-model reverberation room, a recording studio and two different car passenger compartments).

Uncertainties in Acoustical Transfer Functions

Uncertainties in Acoustical Transfer Functions PDF Author: Pascal Dietrich
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832535519
Category : Technology & Engineering
Languages : en
Pages : 220

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Book Description
Measured transfer functions of acoustic systems are often used to derive single-number parameters. The uncertainty analysis is commonly focused on the derived parameters but not on the transfer function as the primary quantity. This thesis presents an approach to assess the uncertainty contributions in these transfer functions by using analytic models. Uncertainties caused by the measurement method are analyzed with a focus on the underlying signal processing. In particular, the influence of nonlinearities in the acoustic measurement chain are modeled to predict artifacts in the measured signals and hence the calculated acoustic transfer function. Secondly, characterization methods commonly applied in the field of signal processing are linked to the acoustic scenarios and the main influencing parameters. Acoustic parameters are then derived analytically and by means of Monte Carlo simulations considering the uncertainty of these input parameters. In order to provide airborne applications, analytic models for sound barrier and room acoustic measurements are developed incorporating the directivity and the orientation of the sound source as well as the positions of sources and receivers. The simulated uncertainty contributions are validated by measurements. The same approach is also applied to structure-borne sound applications.

Proceedings of the EAA Joint Symposium on Auralization and Ambisonics 2014

Proceedings of the EAA Joint Symposium on Auralization and Ambisonics 2014 PDF Author: Weinzierl, Stefan
Publisher: Universitätsverlag der TU Berlin
ISBN: 3798327041
Category :
Languages : en
Pages : 200

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Book Description
In consideration of the remarkable intensity of research in the field of Virtual Acoustics, including different areas such as sound field analysis and synthesis, spatial audio technologies, and room acoustical modeling and auralization, it seemed about time to organize a second international symposium following the model of the first EAA Auralization Symposium initiated in 2009 by the acoustics group of the former Helsinki University of Technology (now Aalto University). Additionally, research communities which are focused on different approaches to sound field synthesis such as Ambisonics or Wave Field Synthesis have, in the meantime, moved closer together by using increasingly consistent theoretical frameworks. Finally, the quality of virtual acoustic environments is often considered as a result of all processing stages mentioned above, increasing the need for discussions on consistent strategies for evaluation. Thus, it seemed appropriate to integrate two of the most relevant communities, i.e. to combine the 2nd International Auralization Symposium with the 5th International Symposium on Ambisonics and Spherical Acoustics. The Symposia on Ambisonics, initiated in 2009 by the Institute of Electronic Music and Acoustics of the University of Music and Performing Arts in Graz, were traditionally dedicated to problems of spherical sound field analysis and re-synthesis, strategies for the exchange of ambisonics-encoded audio material, and – more than other conferences in this area – the artistic application of spatial audio systems. This publication contains the official conference proceedings. It includes 29 manuscripts which have passed a 3-stage peer-review with a board of about 70 international reviewers involved in the process. Each contribution has already been published individually with a unique DOI on the DepositOnce digital repository of TU Berlin. Some conference contributions have been recommended for resubmission to Acta Acustica united with Acustica, to possibly appear in a Special Issue on Virtual Acoustics in late 2014. These are not published in this collection.

Directivity Based Multichannel Audio Signal Processing For Microphones in Noisy Acoustic Environments

Directivity Based Multichannel Audio Signal Processing For Microphones in Noisy Acoustic Environments PDF Author: Simon Grimm
Publisher: Springer
ISBN: 3658251522
Category : Technology & Engineering
Languages : en
Pages : 130

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Book Description
Simon Grimm examines new multi-microphone signal processing strategies that aim to achieve noise reduction and dereverberation. Therefore, narrow-band signal enhancement approaches are combined with broad-band processing in terms of directivity based beamforming. Previously introduced formulations of the multichannel Wiener filter rely on the second order statistics of the speech and noise signals. The author analyses how additional knowledge about the location of a speaker as well as the microphone arrangement can be used to achieve further noise reduction and dereverberation.

Sound Reinforcement for Audio Engineers

Sound Reinforcement for Audio Engineers PDF Author: Wolfgang Ahnert
Publisher: CRC Press
ISBN: 1000627098
Category : Music
Languages : en
Pages : 450

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Book Description
Sound Reinforcement for Audio Engineers illustrates the current state of the art in sound reinforcement. Beginning with an outline of various fields of applications, from sports venues to religious venues, corporate environments and cinemas, this book is split into 11 chapters covering room acoustics, loudspeakers, microphones and acoustic modelling among many other topics. This comprehensive book packed with references and a historical overview of sound reinforcement design is an essential reference book for students of acoustics and electrical engineering, but also for engineers looking to expand their knowledge of designing sound reinforcement systems.

Noise and Vibration Mitigation for Rail Transportation Systems

Noise and Vibration Mitigation for Rail Transportation Systems PDF Author: Jens C.O. Nielsen
Publisher: Springer
ISBN: 3662448327
Category : Technology & Engineering
Languages : en
Pages : 724

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Book Description
The book reports on the 11th International Workshop on Railway Noise, held on 9 – 13 September, 2013, in Uddevalla, Sweden. The event, which was jointly organized by the Competence Centre Chalmers Railway Mechanics (CHARMEC) and the Departments of Applied Mechanics and Applied Acoustics at Chalmers University of Technology in Gothenburg, Sweden, covered a broad range of topics in the field of railway noise and vibration, including: prospects, legal regulations and perceptions; wheel and rail noise; prediction, measurements and monitoring; ground-borne vibration; squeal noise and structure-borne noise; and aerodynamic noise generated by high-speed trains. Further topics included: resilient track forms; grinding, corrugation and roughness; and interior noise and sound barriers. This book, which consists of a collection of peer-reviewed papers originally submitted to the workshop, not only provides readers with an overview of the latest developments in the field, but also offers scientists and engineers essential support in their daily efforts to identify, understand and solve a number of problems related to railway noise and vibration, and to achieve their ultimate goal of reducing the environmental impact of railway systems.

Handbook for Sound Engineers

Handbook for Sound Engineers PDF Author: Glen Ballou
Publisher: CRC Press
ISBN: 1135016658
Category : Technology & Engineering
Languages : en
Pages : 2834

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Book Description
Handbook for Sound Engineers is the most comprehensive reference available for audio engineers, and is a must read for all who work in audio. With contributions from many of the top professionals in the field, including Glen Ballou on interpretation systems, intercoms, assistive listening, and fundamentals and units of measurement, David Miles Huber on MIDI, Bill Whitlock on audio transformers and preamplifiers, Steve Dove on consoles, DAWs, and computers, Pat Brown on fundamentals, gain structures, and test and measurement, Ray Rayburn on virtual systems, digital interfacing, and preamplifiers, Ken Pohlmann on compact discs, and Dr. Wolfgang Ahnert on computer-aided sound system design and room-acoustical fundamentals for auditoriums and concert halls, the Handbook for Sound Engineers is a must for serious audio and acoustic engineers. The fifth edition has been updated to reflect changes in the industry, including added emphasis on increasingly prevalent technologies such as software-based recording systems, digital recording using MP3, WAV files, and mobile devices. New chapters, such as Ken Pohlmann’s Subjective Methods for Evaluating Sound Quality, S. Benjamin Kanters’s Hearing Physiology—Disorders—Conservation, Steve Barbar’s Surround Sound for Cinema, Doug Jones’s Worship Styles in the Christian Church, sit aside completely revamped staples like Ron Baker and Jack Wrightson’s Stadiums and Outdoor Venues, Pat Brown’s Sound System Design, Bob Cordell’s Amplifier Design, Hardy Martin’s Voice Evacuation/Mass Notification Systems, and Tom Danley and Doug Jones’s Loudspeakers. This edition has been honed to bring you the most up-to-date information in the many aspects of audio engineering.

The Journal of the Acoustical Society of America

The Journal of the Acoustical Society of America PDF Author:
Publisher:
ISBN:
Category : Music
Languages : en
Pages : 764

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Book Description