<p>Humans are able to hear and detect small changes in sound across a wide dynamic range despite limited dynamic ranges of individual auditory nerve fibers. One mechanism that may adjust the dynamic range is the medial olivocochlear reflex (MOCR), a bilateral sound-activated system which decreases amplification of sound by the outer hair cells in the cochlea. Much of the previous physiological MOCR research has used long broadband noise elicitors. In behavioral measures of gain reduction, a fairly short elicitor has been found to be maximally effective for an on-frequency, tonal elicitor. However, the effect of the duration of broadband noise elicitors on behavioral tasks is unknown. Additionally, MOCR effects measured using otoacoustic emissions (OAEs), have not consistently shown a positive correlation with behavioral gain reduction tasks. This finding seems counterintuitive if both measurements share a common generation mechanism. The current study measured the effects of ipsilateral broadband noise elicitor duration on psychoacoustic gain reduction (Chapter 2) and transient-evoked OAEs (TEOAEs) (Chapter 3) estimated from a forward-masking paradigm. Changes in the TEOAE were measured in terms of magnitude and phase. When phase was accounted for in the TEOAEs, the time constants were approximately equal to the psychoacoustic time constants, and were relatively short (~80 ms). When only changes in TEOAE magnitude were measured, and phase was omitted, the average time constants were longer (~172-ms). Overall, the psychoacoustic and physiological data were consistent with the timecourse of gain reduction by the MOCR. However, when the magnitudes from these data were directly compared in a linear mixed-effects model (Chapter 4), no positive predictive relationship was found, and in some cases there was a significant negative association between the physiological and psychoacoustic measures of gain reduction as a function of elicitor duration. The multitude of factors involved in this relationship are discussed, as are the implications of dynamic range adjustment in everyday listening conditions (noisy backgrounds) in both normal and hearing impaired listeners (Chapter 5).</p>

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George Crumb ist bekannt dafür, dass er in seinen Kompositionen mit einer großen Palette an Klangfarben arbeitet. Im Trio Vox Balaenae findet sich mit der Besetzung Electric Flute, Electric Cello, Electric Piano – drei Instrumentalgruppen plus elektronische Verstärkung – ein besonders vielfältiger Klangfarbenreichtum. Die vorliegende Analyse zeigt, dass ein wesentlicher Ausdruckgehalt des Stückes von den Klangfarben selbst transportiert wird. Als Rahmen für die hermeneutische Analyse dieser Klangfarbenstruktur dient Rebecca Leydons psychoakustischer Ansatz evidence of bodies: Timbre verweise grundsätzlich auf den Körper zurück, der den gehörten Klang hervorgebracht hat. So weist Leydon verschiedenen Klängen verschiedene Grade an Körperlichkeit zu und knüpft an das musikalische Spiel mit den verschiedenen Körperlichkeiten von Klängen dramaturgische Konzepte. Die vorliegende Analyse greift diesen Ansatz auf und entwickelt ihn weiter, um den Ausdrucksgehalt von Vox Balaenae herauszuarbeiten. / George Crumb is known for using a great variety of timbre in his compositions. This is most certainly true for his Trio Vox Balaenae for Electric Flute, Electric Cello, Electric Piano, a composition which employs three different types of instruments; winds, strings, and keys, with electric amplification. The presented analysis will show that the expressive content of the piece is transported by timbre. This timbral analysis builds on Rebecca Leydon’s psychoacoustic theory of timbre, which she calls ›evidence of bodies‹: namely, a sound’s timbre is the audible evidence of the material nature of the body which produced the sound. Following this, Leydon connects different degrees of embodiment to different timbres ranging from the disembodied to sheer materiality of matter. This allows her to reveal timbral trajectories in pieces from which narratives can be drawn. The presented hermeneutic analysis of Vox Balaenae builds on Leydon’s theory and explores further timbral trajectories and narratives in order to reveal the expressive content of the piece.

Jenseits ihrer Tonhöhe i.e. S. können Töne in ihrem Klangcharakter (timbre) unterschieden werden, und dies auch im Zusammenspiel. Timbre ist jedoch eine schlecht definierte Kategorie, ein Sammelbegriff. Bereits im 19. Jahrhundert versuchten Hermann von Helmholtz und Carl Stumpf eine präzisere Bestimmung zu finden. Die von ihnen angenommene multidimensionale Struktur ist heute durch moderne Skalierungstechniken benutzende Forschungen bestätigt und erweitert. Die Ergebnisse zeigen vier Dimensionen: hard/sharp vs. soft/dull, tonal vs. noisy, empty vs. full, compact vs. pure. Beabsichtigt war mit diesem Artikel jedoch nicht nur psychoakustische Befunde vorzustellen, sondern auch kompositorische Techniken des Komponierens mit Klangcharakteren, so bei Schönberg, Cowell, Rudhyar, Ligeti. Jedoch hat eine Eigenschaft von Tönen und Klängen, nämliche die von Debussy benutzte räumliche Dimension, die Wissenschaft bis heute kaum interessiert. Ein Hinweis auf die Theorie von Ernst Kurth zeigt, dass noch immer viele Fragen mit dem Regenschirmbegriff ›Timbre‹ verbunden sind. / Beyond their pitch, tones can be thought of as differing in sound characteristics (timbre) by which they can be segregated simultaneously from one another. However, timbre is an ill-defined category: it is a catchall term of several sound qualities. Already in the 19th century Hermann von Helmholtz and Carl Stumpf tried to find a more precise description. Their assumption about multidimensional structure of timbre-attributes has been confirmed today and augmentated by researches using modern scaling techniques. The results show four dimensions: hard/sharp vs. soft/dull, tonal vs. noisy, empty vs. full, and compact vs. pure. The purpose of this article is not only to report psycho-acoustic results but also to show techniques of composing with the timbre-factors by Schoenberg, Cowell, Rudhyar, and Ligeti. However, one attribute of tones and sounds, namely, its spatial dimension such as that used by Debussy has hardly interested the scientists of today. A clue to the theory of Ernst Kurth reveals that still a lot of questions surround the term ›timbre‹.

Thesis (MMus (Music))--University of Stellenbosch, 2005. / In this thesis, an attempt is made to create an aesthetically pleasing musical scale based on the ratio of phi. Precedents for the application of phi in aesthetic fields exist; noteworthy is Le Corbusier’s architectural works, the measurements of which are based on phi. A brief discussion of the unique mathematical properties of phi is given, followed by a discussion of the manifestations of phi in the physical ratios as they appear in animal and plant life. Specific scales which have found an application in art music are discussed, and the properties to which their success is attributable are identified. Consequently, during the design of the phi scale, these characteristics are incorporated. The design of the phi scale is facilitated by the use of the most sophisticated modern computer software in the field of psychacoustics. During the scale’s design process, particular emphasis is placed on the requirement of obtaining maximal sensory consonance. For this reason, an in-depth discussion of the theories regarding consonance perception is undertaken. During this discussion, the reader’s attention is drawn to the difference between musical and perceptual consonance, and a discussion of the developmental history of musical consonance is given. Lastly, the scale is tested to see whether it complies with the requirements for successful scales.

Este documento trata do estudo de sistemas de controle de ruído e qualidade sonora em aplicações próprias da indústria da mobilidade, e da avaliação inovadora do seu desempenho com base em métricas da psico-acústica relevantes para esta área como Loudness, Roughness e Tonality. Uma metodologia de projeto e implantação de sistemas de controle ativo com base em métricas da psico-acústica é estabelecida. Os desafios se encontram, primeiramente, na definição do conjunto de atributos temporais e espectrais do distúrbio de entrada, responsável pelas condições auditivas indesejáveis que são identificados a partir da análise da emissão acústica sintetizada de um motor de combustão interna de um veículo automotivo. Algoritmos e metodologias computacionais são usados de forma extensiva para simulação e análise, integrando as áreas de projeto de sistemas de controle e psico-acústica. Um algoritmo adaptativo de controle de qualidade sonora é desenvolvido para solucionar problemas gerados pela interação em amplitude e/ou fase relativa das componentes de banda estreita em distúrbios de característica harmônica. Finalmente, os conceitos avaliados de forma numérica são validados experimentalmente, permitindo não só a análise critica do desempenho psico-acústico dos controladores, como também da própria metodologia de projeto adotada, o que é realizado com auxílio de um mock-up de um veículo automotivo sujeito a distúrbios de características psico-acústicas relevantes para o problema proposto. / This master thesis deals with the study of active noise and sound quality control systems in automotive applications, and the innovative assessment of their performance based on relevant psychoacoustic metrics in this area such as Loudness, Roughness and Tonality. A methodology for designing and implementing active control systems based on psychoacoustic metrics is established. The main challenges reside in defining the set of time-frequency attributes of the disturbance, responsible for the undesirable auditory stimuli. Computer algorithms are used extensively for simulating and analyzing the disturbance, which is a synthesized internal combustion engine noise, integrating both the control system design and psychoacoustics areas. An adaptive active sound quality control algorithm is proposed to resolve the amplitude and/or relative phase interactions among the narrowband components of the multi-harmonic disturbance. Eventually, the numerical results are correlated with real experiments, allowing not only a critical analysis of the psychoacoustic performance of the controllers, but also of the proposed design methodology, which is accomplished with the aid of a vehicle\'s mock-up, subject to disturbances of relevant psychoacoustic characteristics to the proposed problem.

A dissonância sensorial é um conceito que restringe a noção da dissonância à sua dimensão psicofísica, por meio do fenômeno psicoacústico conhecido como rugosidade. Esse conceito foi explorado neste trabalho experimentalmente tendo como foco o teste da hipótese de que é possível modelar a dissonância sensorial em escalas do temperamento por igual utilizando-se timbres inarmônicos. A dissertação é dividida em 5 partes. No capítulo 2, realiza-se uma revisão bibliográfica compilando os principais modelos de dissonância sensorial baseados em estudos experimentais, e uma revisão do sistema de afinação conhecido como temperamento por igual. No capítulo 3 apresenta-se uma proposta de síntese de espectros inarmônicos que modelam a dissonância para o temperamento por igual. Em seguida, apresenta-se um teste subjetivo realizado que avaliou a dissonância sensorial em espectros construídos com dissonância modelada para uma escala temperada de 8 partes iguais. No capítulo 4, são apresentadas aplicações artísticas realizadas, consequentes do estudo da modelagem da dissonância sensorial em escalas do temperamento por igual, como uma proposta de mapeamento de escalas em um teclado MIDI e dois relatos composicionais. Discussões acerca dos resultados e apontamentos para trabalhos futuros são abordados no capítulo final. Os resultados da pesquisa apontam para o fato de os modelos de dissonância sensorial estudados não serem suficientemente eficazes na tarefa de realizar uma avaliação precisa do fenômeno da dissonância sensorial em sons inarmônicos. Além disso, como resultado, abriram-se novas perspectivas para práticas artísticas com dissonância modelada, onde discutimos o impacto do uso dos modelos de dissonância na prática composicional e no contexto da música atual. / Sensory dissonance is a concept that restricts the dissonance to their psychophysical dimension, through the psychoacoustics phenomenon known as roughness. This concept was explored in this work experimentally, based on the assumption that it is possible to model the sensory dissonance in equal tempered scales, using inharmonic spectra. Our dissertation is divided into five parts. Firstly, on chapter 2, a literature review exposing the main models of sensory dissonance that are based on experimental studies is presented, as well as a revision of the equal tempered scale system. Secondly, the first part of Chapter 3 presents a method and an algorithm to synthetize inharmonic spectra that models the dissonance for equal tempered scales. Then, in the second part of chapter 3, we expose an experimental test that aims to evaluate the sensory dissonance on a spectrum generated to model the dissonance in a scale that divides the octave into 8 equal parts. On chapter 4, we propose artistic applications using the dissonance studies developed in this work, as well as a prototype of equal tempered scales controller using a MIDI keyboard and two compositional reports. Finally, the results of this research are shown in chapter 5, that highlights the fact that the models of sensory dissonance approached in this dissertation are not effective to calculate a precise estimation of sensory dissonance in inharmonic spectra. Besides that, as a result, new perspectives for artistic practices using dissonance modeling are presented, as we discuss the impact of dissonance models in the context of composition and contemporary music.

La variabilité inter-individuelle en localisation auditive a été étudiée à travers plusieurs expérimentations. La première expérimentation a exploré la variabilité inter-individuelle en localisation auditive de sources sonores virtuelles (HRTFs individuelles et non individuelles) dans une population de 25 auditeurs naïfs préalablement soumis à un entraînement procédural. D'après nos résultats, la variabilité inter-individuelle dans la dimension gauche/droite pourrait être liée à une préférence individuelle vers un type d'indices parmi ceux utilisables pour la localisation dans cette dimension (indices binauraux/spectraux). Dans les dimensions haut/bas et avant/arrière, la variabilité inter-individuelle pourrait être liée à l'attention spatiale et à sa variation entre les zones de l'espace. Une seconde expérimentation réalisée chez les mêmes auditeurs a montré qu'une amélioration des capacités de localisation était possible par un entraînement par feedback visuel ou audio-moteur. Cette amélioration était souvent fonction de la performance avant entraînement, conduisant ainsi à une réduction de la variabilité inter-individuelle après entraînement. La variabilité inter-individuelle dans la dimension haut/bas après entraînement était en partie expliquée par l'activité du faisceau olivocochléaire efférent médian (FOCEM), structure du système auditif probablement impliquée dans le codage des indices spectraux de localisation. Ce résultat a été conforté par les résultats d'une troisième expérimentation qui ont révélé que les auditeurs dont la performance de localisation était la moins altérée dans le bruit étaient ceux dont le FOCEM avait été déterminé comme le plus actif. / Several experiments were performed to investigate interindividual variability in auditory localization. The first experiment explored interindividual variability in the localization of virtual sound sources (individualized and non-individualized HRTFs) in 25 naive listeners following procedural training. The results suggest that interindividual variability in localization performance in the left-right dimension stems from interindividual differences in the use of the different types of cues available for sound localization in this dimension (binaural/spectral cues). Interindividual variability in sound-localization performance in the up-down and front-back dimensions appears to be related primarily to spatial attention and to its variation across the area of space. A second experiment in the same group of listeners showed that localization performance can be improved by the provision of visual or auditory-motor feedback. The improvement depended upon pre-training performance, in such a way that interindividual variability in performance was smaller after training than before training. In addition, interindividual variability in the up-down dimension after training was found to be related to interindividual differences in the activity of the medial olivocochlear bundle (MOCB), an efferent auditory system that is currently likely thought to be involved in the processing of spectral cues for sound localization. This result was supported by the results of a third experiment which revealed that the listeners in whom localization performance was least impacted by background noise were those in whom the strongest MOCB had been measured.

A dissonância sensorial é um conceito que restringe a noção da dissonância à sua dimensão psicofísica, por meio do fenômeno psicoacústico conhecido como rugosidade. Esse conceito foi explorado neste trabalho experimentalmente tendo como foco o teste da hipótese de que é possível modelar a dissonância sensorial em escalas do temperamento por igual utilizando-se timbres inarmônicos. A dissertação é dividida em 5 partes. No capítulo 2, realiza-se uma revisão bibliográfica compilando os principais modelos de dissonância sensorial baseados em estudos experimentais, e uma revisão do sistema de afinação conhecido como temperamento por igual. No capítulo 3 apresenta-se uma proposta de síntese de espectros inarmônicos que modelam a dissonância para o temperamento por igual. Em seguida, apresenta-se um teste subjetivo realizado que avaliou a dissonância sensorial em espectros construídos com dissonância modelada para uma escala temperada de 8 partes iguais. No capítulo 4, são apresentadas aplicações artísticas realizadas, consequentes do estudo da modelagem da dissonância sensorial em escalas do temperamento por igual, como uma proposta de mapeamento de escalas em um teclado MIDI e dois relatos composicionais. Discussões acerca dos resultados e apontamentos para trabalhos futuros são abordados no capítulo final. Os resultados da pesquisa apontam para o fato de os modelos de dissonância sensorial estudados não serem suficientemente eficazes na tarefa de realizar uma avaliação precisa do fenômeno da dissonância sensorial em sons inarmônicos. Além disso, como resultado, abriram-se novas perspectivas para práticas artísticas com dissonância modelada, onde discutimos o impacto do uso dos modelos de dissonância na prática composicional e no contexto da música atual. / Sensory dissonance is a concept that restricts the dissonance to their psychophysical dimension, through the psychoacoustics phenomenon known as roughness. This concept was explored in this work experimentally, based on the assumption that it is possible to model the sensory dissonance in equal tempered scales, using inharmonic spectra. Our dissertation is divided into five parts. Firstly, on chapter 2, a literature review exposing the main models of sensory dissonance that are based on experimental studies is presented, as well as a revision of the equal tempered scale system. Secondly, the first part of Chapter 3 presents a method and an algorithm to synthetize inharmonic spectra that models the dissonance for equal tempered scales. Then, in the second part of chapter 3, we expose an experimental test that aims to evaluate the sensory dissonance on a spectrum generated to model the dissonance in a scale that divides the octave into 8 equal parts. On chapter 4, we propose artistic applications using the dissonance studies developed in this work, as well as a prototype of equal tempered scales controller using a MIDI keyboard and two compositional reports. Finally, the results of this research are shown in chapter 5, that highlights the fact that the models of sensory dissonance approached in this dissertation are not effective to calculate a precise estimation of sensory dissonance in inharmonic spectra. Besides that, as a result, new perspectives for artistic practices using dissonance modeling are presented, as we discuss the impact of dissonance models in the context of composition and contemporary music.

Este documento trata do estudo de sistemas de controle de ruído e qualidade sonora em aplicações próprias da indústria da mobilidade, e da avaliação inovadora do seu desempenho com base em métricas da psico-acústica relevantes para esta área como Loudness, Roughness e Tonality. Uma metodologia de projeto e implantação de sistemas de controle ativo com base em métricas da psico-acústica é estabelecida. Os desafios se encontram, primeiramente, na definição do conjunto de atributos temporais e espectrais do distúrbio de entrada, responsável pelas condições auditivas indesejáveis que são identificados a partir da análise da emissão acústica sintetizada de um motor de combustão interna de um veículo automotivo. Algoritmos e metodologias computacionais são usados de forma extensiva para simulação e análise, integrando as áreas de projeto de sistemas de controle e psico-acústica. Um algoritmo adaptativo de controle de qualidade sonora é desenvolvido para solucionar problemas gerados pela interação em amplitude e/ou fase relativa das componentes de banda estreita em distúrbios de característica harmônica. Finalmente, os conceitos avaliados de forma numérica são validados experimentalmente, permitindo não só a análise critica do desempenho psico-acústico dos controladores, como também da própria metodologia de projeto adotada, o que é realizado com auxílio de um mock-up de um veículo automotivo sujeito a distúrbios de características psico-acústicas relevantes para o problema proposto. / This master thesis deals with the study of active noise and sound quality control systems in automotive applications, and the innovative assessment of their performance based on relevant psychoacoustic metrics in this area such as Loudness, Roughness and Tonality. A methodology for designing and implementing active control systems based on psychoacoustic metrics is established. The main challenges reside in defining the set of time-frequency attributes of the disturbance, responsible for the undesirable auditory stimuli. Computer algorithms are used extensively for simulating and analyzing the disturbance, which is a synthesized internal combustion engine noise, integrating both the control system design and psychoacoustics areas. An adaptive active sound quality control algorithm is proposed to resolve the amplitude and/or relative phase interactions among the narrowband components of the multi-harmonic disturbance. Eventually, the numerical results are correlated with real experiments, allowing not only a critical analysis of the psychoacoustic performance of the controllers, but also of the proposed design methodology, which is accomplished with the aid of a vehicle\'s mock-up, subject to disturbances of relevant psychoacoustic characteristics to the proposed problem.