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Finite Element Simulation of External Ear Sound Fields for the Optimization of Eardrum-related Measurements

Finite Element Simulation of External Ear Sound Fields for the Optimization of Eardrum-related Measurements PDF Author: Sebastian Schmidt
Publisher: Logos Verlag Berlin GmbH
ISBN: 383252262X
Category : Technology & Engineering
Languages : en
Pages : 154

Book Description
The sound pressure pT at the human eardrum has essential advantages as reference signal in audiological and psychoacoustical experiments. Unfortunately, precise pressure measurements very close to the tympanic membrane are difficult. In practice, the microphone has to be positioned at a certain distance from the eardrum. The measured pressure then has to be transformed to the eardrum. As a "classical" approach for the estimation of the necessary transfer function, an acoustical network model of the ear canal is developed from geometrical data of the canal (cross-sectional area function) which is in turn determined from measurements of its acoustical input impedance. Such methods, however, do not provide robust results. In this thesis, the concept of one-dimensional models of the ear canal is examined to find the origin of these errors. For this purpose, the sound field at the human external ear was analyzed using finite element models. Inside the canal, irregular three-dimensional structures occur that cannot be modelled accurately using classical one-dimensional network concepts. Upon these findings, an accurate, efficient and highly feasible method for the estimation of pT was developed. Equal-loudness level contours with reference to the eardrum pressure that were measured as pilot application of the new method are presented.

Finite Element Simulation of External Ear Sound Fields for the Optimization of Eardrum-related Measurements

Finite Element Simulation of External Ear Sound Fields for the Optimization of Eardrum-related Measurements PDF Author: Sebastian Schmidt
Publisher: Logos Verlag Berlin GmbH
ISBN: 383252262X
Category : Technology & Engineering
Languages : en
Pages : 154

Book Description
The sound pressure pT at the human eardrum has essential advantages as reference signal in audiological and psychoacoustical experiments. Unfortunately, precise pressure measurements very close to the tympanic membrane are difficult. In practice, the microphone has to be positioned at a certain distance from the eardrum. The measured pressure then has to be transformed to the eardrum. As a "classical" approach for the estimation of the necessary transfer function, an acoustical network model of the ear canal is developed from geometrical data of the canal (cross-sectional area function) which is in turn determined from measurements of its acoustical input impedance. Such methods, however, do not provide robust results. In this thesis, the concept of one-dimensional models of the ear canal is examined to find the origin of these errors. For this purpose, the sound field at the human external ear was analyzed using finite element models. Inside the canal, irregular three-dimensional structures occur that cannot be modelled accurately using classical one-dimensional network concepts. Upon these findings, an accurate, efficient and highly feasible method for the estimation of pT was developed. Equal-loudness level contours with reference to the eardrum pressure that were measured as pilot application of the new method are presented.

Individualized Binaural Technology

Individualized Binaural Technology PDF Author: Bruno Sanches Masiero
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832532749
Category : Science
Languages : en
Pages : 210

Book Description
In this work the importance of individualization in binaural technique is investigated. The results extend the present knowledge on the efficient measurement of individual head-related transfer functions (HRTFs) and highlight the importance of individual equalization filters in binaural reproduction, using both loudspeakers and headphones. Moreover, an integrated framework for the calculation of such equalization filters is presented. An innovative measurement setup was developed to allow the fast acquisition of individual HRTFs. The hardware was designed to be compatible with the range extrapolation technique. An individual HRTF dataset with 4000 directions can be measured in less than 6 minutes with this new setup. A framework was presented that integrates causality constraints to the regularized frequency domain calculation of crosstalk cancellation (CTC) filter. This framework also addresses the switching of active loudspeakers applying a weighted filter calculation method. A sound localization test showed that individualized CTC systems provide performance similar to that of binaural listening while nonindividualized CTC systems provide a significantly lower localization performance. Finally, a robust individual headphone equalization method was proposed. Perceptual tests showed that, in all but one of the tested situations, no audible differences between the original sound source and its binaural auditory display could be perceived.

The Middle Ear

The Middle Ear PDF Author: Sunil Puria
Publisher: Springer Science & Business Media
ISBN: 1461465915
Category : Medical
Languages : en
Pages : 320

Book Description
The middle ear plays a vital role in the sense and sensitivity of hearing. Of the various characteristics that distinguish mammals from other vertebrates, several pertain specifically to the middle-ear system, such as the presence of three middle-ear bones and the four-layer composite structure of the tympanic membrane. The Middle Ear attempts to elucidate the role this system plays in sound transmission, as viewed from both scientific and clinical perspectives.

Glasscock-Shambaugh Surgery of the Ear

Glasscock-Shambaugh Surgery of the Ear PDF Author: Lloyd B. Minor
Publisher: PMPH-USA
ISBN: 9781607950264
Category : Medical
Languages : en
Pages : 828

Book Description
Updated with new color graphics and new video CD of surgical and diagnostic procedures, this 6th edition retains its heritage as the classic textbook in otology and neurotology. Coverage includes scientific foundations and fundamentals, clinical evaluation and rehabilitation and sections on the external ear, inner ear, tympanomastoid compartment, internal auditory canal/Cerebellopontine angle/petrous apex and skull-based surgery. This edition integrates all the latest research in genetics, biotechnical advancements in laser and image-guided systems and clinical innovations and techniques of the past 7 years. Woven throughout is an intriguing historical overview of those who pioneered the early surgical interventions from 1950 to the present and the influences on current clinical practice. Editors of this edition, Julianna Gulya, Lloyd Minor and Dennis Poe are internationally renowned figures in the field of otology/neurotology. This 6th edition enormously benefits from their editorial direction and wealth of knowledge and clinical expertise. SOTE 6 remains the classic text and reference of choice for otolaryngologists and neurosurgeons and an essential addition to the libraries of experienced surgeons, trainees, or those preparing for board exams. New Chapters written by well-recognized leaders that include the latest research and clinical studies include: Tumor Biology Stereotactic Radiosurgery and Radiotherapy Ossicular Reconstruction Management of Cerebrospinal Fluid Leaks Surgical Treatment of Peripheral Vestibular Disorders Hearing Aids Tinnitus Rehabilitation Vestibular Rehabilitation Updated Temporal Bone Dissection Guide

Current Programs

Current Programs PDF Author:
Publisher:
ISBN:
Category : Engineering
Languages : en
Pages : 552

Book Description


Cumulated Index Medicus

Cumulated Index Medicus PDF Author:
Publisher:
ISBN:
Category : Medicine
Languages : en
Pages : 1328

Book Description


Anthropometric Individualization of Head-Related Transfer Functions Analysis and Modeling

Anthropometric Individualization of Head-Related Transfer Functions Analysis and Modeling PDF Author: Ramona Bomhardt
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832545433
Category : Science
Languages : en
Pages : 162

Book Description
Human sound localization helps to pay attention to spatially separated speakers using interaural level and time differences as well as angle-dependent monaural spectral cues. In a monophonic teleconference, for instance, it is much more difficult to distinguish between different speakers due to missing binaural cues. Spatial positioning of the speakers by means of binaural reproduction methods using head-related transfer functions (HRTFs) enhances speech comprehension. These HRTFs are influenced by the torso, head and ear geometry as they describe the propagation path of the sound from a source to the ear canal entrance. Through this geometry-dependency, the HRTF is directional and subject-dependent. To enable a sufficient reproduction, individual HRTFs should be used. However, it is tremendously difficult to measure these HRTFs. For this reason this thesis proposes approaches to adapt the HRTFs applying individual anthropometric dimensions of a user. Since localization at low frequencies is mainly influenced by the interaural time difference, two models to adapt this difference are developed and compared with existing models. Furthermore, two approaches to adapt the spectral cues at higher frequencies are studied, improved and compared. Although the localization performance with individualized HRTFs is slightly worse than with individual HRTFs, it is nevertheless still better than with non-individual HRTFs, taking into account the measurement effort.

Physiological Acoustics

Physiological Acoustics PDF Author: Ernest Glen Wever
Publisher: Princeton University Press
ISBN: 1400876435
Category : Science
Languages : en
Pages : 475

Book Description
This book deals with the ear as an acoustic instrument: as a piece of physical apparatus functioning for the reception of sounds from the outside, for conveying them inward to the auditory sense cells, and finally for producing a mechanical stimulation of these cells. Originally published in 1954. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

Implantable Hearing Devices

Implantable Hearing Devices PDF Author: Chris de Souza
Publisher: Plural Publishing
ISBN: 1635502276
Category : Medical
Languages : en
Pages : 305

Book Description
Implantable Hearing Devices is written for ear, nose, and throat surgeons in training who must know about implantable hearing devices as they advance in otologic surgery. It is also a resource for otologic surgeons desiring to know more about the devices available. The technology is evolving rapidly along with the criteria for candidacy, and this text covers the entire spectrum of implantable hearing devices that are available, including but not limited to cochlear implants. Complex issues are presented in an easy to understand format by a host of internationally well-respected authors. Many practitioners have to refer to multiple resources for answers to their questions because the discipline is changing so rapidly. Implantable Hearing Devices is a clear, concise, but comprehensive book that offers answers to the universal problems that otologic surgeons face. Disclaimer: Please note that ancillary content (such as documents, audio, and video, etc.) may not be included as published in the original print version of this book.

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

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.