The sustained increase in computing performance over the last decades has brought enough computing power to perform significant audio processing in affordable personal computers. Following this revolution, we have witnessed a series of improvements in sound transformation techniques and the introduction of numerous digital audio effects to modify effectively the time, pitch, and loudness dimensions of audio signals. Due to the complex and multi-dimensional nature of timbre however, it is significantly more difficult to achieve meaningful and convincing qualitative transformations. The tools currently available for timbre modifications (e.g. equalizers) do not operate along perceptually meaningful axes of singing voice timbre (e.g. breathiness, roughness, etc.) resulting in a transformation control problem. One of the goals of this work is to examine more intuitive procedures to achieve high-fidelity qualitative transformations explicitly controlling certain dimensions of singing voice timbre. Quantitative measurements (i.e. voice timbre descriptors) are introduced and used as high-level controls in an adaptive processing system dependent on the characteristics observed in the input signal. / The transformation methods use a harmonic plus noise representation from which voice timbre descriptors are derived. This higher-level representation, closer to our perception of voice timbre, offers more intuitive controls over timbre transformations. The topics of parametric voice modeling and timbre descriptor computation are first introduced, followed by a study of the acoustical impacts of voice breathiness variations. A timbre transformation system operating specifically on the singing voice quality is then introduced with accompanying software implementations, including an example digital audio effect for the control and modification of the breathiness quality on normal voices.

Audio signal processing systems for converting two-channel (stereo) recordings to four or five channels are increasingly relevant. These audio upmixers can be used with conventional stereo sound recordings and reproduced with multichannel home theatre or automotive loudspeaker audio systems to create a more engaging and natural-sounding listening experience. This dissertation discusses existing approaches to audio upmixing for recordings of musical performances and presents specific design criteria for a system to enhance spatial sound quality. A new upmixing system is proposed and evaluated according to these criteria and a theoretical model for its behavior is validated using empirical measurements. / The new system removes short-term correlated components from two electronic audio signals using a pair of adaptive filters, updated according to a frequency domain implementation of the normalized-least-means-square algorithm. The major difference of the new system with all extant audio upmixers is that unsupervised time-alignment of the input signals (typically, by up to +/-10 ms) as a function of frequency (typically, using a 1024-band equalizer) is accomplished due to the non-minimum phase adaptive filter. Two new signals are created from the weighted difference of the inputs, and are then radiated with two loudspeakers behind the listener. According to the consensus in the literature on the effect of interaural correlation on auditory image formation, the self-orthogonalizing properties of the algorithm ensure minimal distortion of the frontal source imagery and natural-sounding, enveloping reverberance (ambiance) imagery. / Performance evaluation of the new upmix system was accomplished in two ways: Firstly, using empirical electroacoustic measurements which validate a theoretical model of the system; and secondly, with formal listening tests which investigated auditory spatial imagery with a graphical mapping tool and a preference experiment. Both electroacoustic and subjective methods investigated system performance with a variety of test stimuli for solo musical performances reproduced using a loudspeaker in an orchestral concert-hall and recorded using different microphone techniques. / The objective and subjective evaluations combined with a comparative study with two commercial systems demonstrate that the proposed system provides a new, computationally practical, high sound quality solution to upmixing.

The purpose of this study was to investigate the phenomenon of choral blend through acoustical analysis of individual vocal sounds. One aspect of the study involved identifying and comparing the acoustical qualities of sounds produced in the usual solo manner and sounds produced by the same singers attempting to blend with a unison ensemble. Another aspect of the study involved identifying and comparing the acoustical qualities of vocal sounds identified as blending well and poorly with a unison ensemble. Singers attempting to blend adjust their overall intensity not only to affect the perceived loudness of their tones, but also to facilitate other acoustical changes which are helpful for achieving blend. Vocal blend apparently may be achieved more readily on vowels having few upper partials than on vowels having numerous upper partials. Where vibrato is employed, certain vocal sounds can achieve a good blend even though their fundamental frequencies only approximate the theoretically correct frequency. There apparently is an interaction between the vibrato of a vocal tone and its spectral features, making it advantageous for the singer to adopt mutually beneficial approaches to both factors in order to blend. Vowel modification effective for achieving vocal blend- -at least for sopranos-- appears to consist primarily of changes in the intensity relationships between the vowel formants. Singers' variations in frequency extend beyond the boundaries of any system of tuning or temperament.

Resonant singing creates possibilities with dynamic shading, subtlety of phrasing, and rich vibrant tone that astonishes listeners. Choral singing that employs resonance as a fundamental ensemble virtue yields impressive results that lend themselves well to the varying demands of any choral score. Fortunately, choruses of every level can benefit from an increased understanding of the basic principles of resonance in the singing voice. Research on issues of upper partial energy and the presence of the singer's formant in a choral ensemble has been limited in approach. Many published studies regarding upper partial energy in the choral ensemble are based on what the ensemble is already doing, which is linked to the teaching of that specific director and that specific choir. Research must include a wider range of aesthetic choices with regard to choral unification. Through examining spectrograms that represent the sound of some of the most renowned choirs, it is possible to see that many of these ensembles are producing tone that contains a high level of upper formant energy. Interviews with established conductors reveal approaches and teaching methodologies that reinforce this type of singing. It is possible to teach the individuals in a choir to increase the level of resonance in their voices, creating a collective sound containing a vibrancy that is easier to tune and unify. This paper explores resonance in choral singing by first explaining the basic principles of sound production, then defining a resonant tone as one containing the strong presence in the upper partials generally associated with classically trained singers, and finally discussing how this type of resonance is developed in choirs.

The specific problems investigated involved identifying and describing the characteristics of fundamental frequency, overall intensity, and spectral content in unaccompanied and ensemble performance settings. Additionally, comparisons and descriptions of the relationships among these acoustical parameters were made. Fifteen trombonists were used as research subjects. Each subject recorded a selected musical excerpt in the following performance modes: high register unaccompanied, harmonic, and unison ensemble; and low register unaccompanied and unison ensemble. Tape recordings of these subjects were used in conjunction with certain electronic apparatus to obtain data on frequency, intensity, and spectral content. Based on these data, descriptions of these acoustical parameters and comparisons of unaccompanied and ensemble performance settings were made.

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Mathilde Marchesi played a significant role in vocal education during the nineteenth and early twentieth centuries. Marchesi taught many of the prominent female vocalists of her time and published a wealth of material based on the bel canto style and her own vocal methods. The research presented includes an examination of musical influences in early years, and provides information related to Marchesi's studies with Manuel Garcia II who played an important role in Mathilde's training and future devotion to the bel canto style. Section II defines the Marchesi method, with analysis of her techniques and methodology. Information on three of her most well known students - Nellie Melba, Emma Eames, and her own daughter, Blanche Marchesi, is presented in Section III along with narrative offering insight into Marchesi's personality and character. The thesis concludes with discussion of the viability and applicability of Marchesi's vocal pedagogy one hundred years after her death. / by Joanna Craik. / Thesis (M.A.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

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Acompanha: Oficina de luteria e laboratório de acústica: guia adidático / Como é a relação entre acústica e luteria? Tal pergunta é a que se faz o pesquisador ao início da escrita desta dissertação. Mesma pergunta que faz para cinco professores envolvidos com ensino de luteria, participantes da formação do luthier em cursos de duas instituições brasileiras. Esta pesquisa, diante da questão central, tem como objetivo delinear contribuições para esclarecer e favorecer a relação entre luteria e acústica desvelada na perspectiva de ser-luthier, em experiência e compreensão. Através de um estudo de campo, voltou o olhar para a comunidade formada por professores e estudantes ligados à acústica e luteria, particularmente, nas duas instituições brasileiras, sendo que numa delas o pesquisador se colocou como observador participante. Realizou entrevistas com os professores nas duas instituições. Numa delas, especificamente, participou em sala de aula como professor. Assim, tomou contato com reverberações imediatas da atividade didática nos estudantes em formação como luthiers. Antes da entrada em sala e aula, renovava a perspectiva como professor enquanto elaborava uma estratégia didática para favorecer a relação. Para isto, considerou experiências em campo e base na invenção de uma Ilha de Interdisciplinar de Racionalidade de Gérard Fourez, assim como na Teoria das Situações Didáticas de Guy Brousseau, principalmente, sob a noção de situações adidáticas. Os discursos dos entrevistados foram compreendidos através de uma das maiores lições da fenomenologia, a redução fenomenológica. O pesquisador buscou desvelar o fenômeno (antes estruturado para sua consciência) na descrição de cada entrevistado, ao que contribuíram as experiências em campo. Ao fim, desvelou a relação entre acústica e luteria na perspectiva do ser-luthier. Encontrava as próprias possibilidades de vir a ser luthier. Em conclusão do captado com a pesquisa, uma separação apareceu entre acústica e luteria, como um muro impedindo sua relação. Porém, ao perscrutar a essência através da consciência pura da relação (destituída de preconceitos, limitações, predefinições), o muro apareceu insustentável. A relação está nos fundamentos basais da prática da luteria, que tem a acústica como parte indispensável da formação do luthier. Precisa ser reencontrada no enfrentamento dos desafios da prática, sem ludibriá-los através da estética visual e de modelos predefinidos. Ao mesmo tempo, dependerá da superação dos obstáculos interpostos ao confrontar os desafios, contanto com a colaboração entre diversas perspectivas, bem como com a comunicação e compartilhamento aberto de informações. A reflexão sobre as ações didáticas do pesquisador e pela própria redução fenomenológica foi constante. Dela, emergiu um caminho para favorecer a relação entre acústica e luteria. O produto final das experiências e reflexões aparece no Guia Adidático que acompanha esta dissertação. / How is the relation between acoustics and lutherie? The researcher asks himself this question at the beginning of the dissertation, the same that directs to five teachers involved in lutherie teaching, participants in the luthier formation in courses of two Brazilian institutions. This research, from the initial question, aims to delineate contributions to clarify and favor the relation between lutherie and acoustics unveiled in the perspective of the being that takes it in experience and understanding. Delineated as a field study, looks inside a community formed by teachers and students correlated to acoustics and lutherie, particularly in the two Brazilian institutions. In one institution the researchers becomes a participant observer, where conducts interviews with five teachers in both institutions. In one of them, specifically, toked participant observation in classroom. So takes contact with effects of the immediate implications of (your and by others teachers) didactic's activities on students of lutherie. Concomitantly, developed a didactic strategy to favor the relation between acoustics and lutherie, considering experiences in the field and reasoned in the Interdisciplinary Island of Rationality of Gérard Fourez, as well as Theory of the Didactic Situations of Guy Brousseau, especially the concept of adidactic situation. The discourses of the interviewers are understood through one of the greatest lessons of phenomenology, the phenomenological reduction. The researcher sets out to unveil the phenomenon, previously structured for him, to which the experiences in the field contribute. At the end, the relation between acoustics and lutherie is revealed in being-luthier perspective. Also as a becoming-luthier, taking part in the possibility luthier formation. By field study and the phenomenological reduction, a separation was shown between acoustic and lutherie as a wall blocking the relation. However, inside pure consciousness of relation (leaving of prejudice, limitation, determinism), the wall seemed unsustainable. The relation is in basal foundations for practice lutherie, that take the acoustic how indispensable component of luthier formation. Need to be rediscovered through facing practice’s challenges, without cod them by aesthetics and predefined templates. At same time, will depend overcoming obstacles step in practice, counting on collaboration by others perspectives, as well with open communication and sharing information. In the constant reflection of the didactic actions of the researcher, from the beginning to end of the research, he elaborates and re-elaborates didactic's activities. The experiences and reflections conform an Adidactic Guide, as technical production parallel to present dissertation.