Academic literature on the topic 'Woodwind instruments – Acoustics'

This thesis presents a number of methods for the computational analysis of woodwind instruments. The Transmission-Matrix Method (TMM) for the calculation of the input impedance of an instrument is described. An approach based on the Finite Element Method (FEM) is applied to the determination of the transmission-matrix parameters of woodwind instrument toneholes, from which new formulas are developed that extend the range of validity of current theories. The effect of a hanging keypad is investigated and discrepancies with current theories are found for short toneholes. This approach was applied as well to toneholes on a conical bore, and we conclude that the tonehole transmission matrix parameters developed on a cylindrical bore are equally valid for use on a conical bore.A boundary condition for the approximation of the boundary layer losses for use with the FEM was developed, and it enables the simulation of complete woodwind instruments. The comparison of the simulations of instruments with many open or closed toneholes with calculations using the TMM reveal discrepancies that are most likely attributable to internalor external tonehole interactions. This is not taken into account in the TMM and poses a limit to its accuracy. The maximal error is found to be smaller than 10 cents. The effect of the curvature of the main bore is investigated using the FEM. The radiation impedance of a wind instrument bell is calculated using the FEM and compared to TMM calculations; we conclude that the TMM is not appropriate for the simulation of flaring bells.Finally, a method is presented for the calculation of the tonehole positions and dimensions under various constraints using an optimization algorithm, which is based on the estimation of the playing frequencies using the Transmission-Matrix Method. A number of simple woodwind instruments are designed using this algorithm and prototypes evaluated.
Cette thèse présente des méthodes pour la conception d'instruments de musique à vent à l'aide de calculs scientifiques. La méthode des matrices de transfert pour le calcul de l'impédance d'entrée est décrite. Une méthode basée sur le calcul par Éléments Finis est appliquée à la détermination des paramètres des matrices de transfert des trous latéraux des instruments à vent, à partir desquels de nouvelles équations sont développées pour étendre la validité deséquations de la littérature. Des simulations par Éléments Finis de l'effet d'une clé suspendue au-dessus des trous latéraux donnent des résultats différents de la théorie pour les trous courts. La méthode est aussi appliquée à des trous sur un corps conique et nous concluons que les paramètres des matrices de transmission développées pour les tuyaux cylindriques sont également valides pour les tuyaux coniques.Une condition frontière pour l'approximation des pertes viscothermiques dans les calculs par Éléments Finis est développée et permet la simulation d'instruments complets. La comparaison des résultats de simulations d'instruments avec plusieurs trous ouverts ou fermés montre que la méthode des matrices de transfert présente des erreurs probablement attribuables aux interactions internes et externes entre les trous. Cet effet n'est pas pris en compte dans laméthode des matrices de transfert et pose une limite à la précision de cette méthode. L'erreur maximale est de l'ordre de 10 cents. L'effet de la courbure du corps de l'instrument est étudié avec la méthode des Éléments Finis. L'impédance de rayonnement du pavillon d'un instrument est calculée avec la méthode des matrices de transfert et comparée aux résultats de la méthode des Éléments Finis; nous concluons que la méthode des matrices de transfert n'estpas appropriée à la simulation des pavillons.Finalement, une méthode d'optimisation est présentée pour le calcul de la position et des dimensions des trous latéraux avec plusieurs contraintes, qui est basé sur l'estimation des fréquences de jeu avec la méthode des matrices de transfert. Plusieurs instruments simples sont conçus et des prototypes fabriqués et évalués.

The xiao is a Chinese end-blown flute with a history over a thousand years and well known in China for its elegant sound. The xiao is little known outside China, but its close relative, the Japanese shakuhachi, is better known internationally. The xiao has not been well developed or standardized (because of the bamboo's varying geometries) for the contemporary musical requirements and is imperfect in tuning, tone range, tonal stability and playability of high notes. In acoustics, all these imperfections can be characterized by the acoustical impedance. As an air-reed instrument, the xiao plays at its input impedance minima. In the work reported in this thesis, the xiao was modelled by a modified transmission-matrix method, and an impedance tube was built for measuring the xiao's acoustical impedance to validate the model (accurate to a few cents). Then player effects were taken into account by an empirical formula, and the model was able to predict the playing frequencies of a xiao with any tone hole positions, sizes, and arbitrary bore shape along the symmetry axis. Based on this model, numerical optimizations were applied to improve the xiao, and a set of optimal fingerings for the xiao were obtained systematically. Several xiaos made from PVC pipes with optimized tone holes show good tuning over three octaves. A xiao with additionally optimized bore shape was machined out of acrylic, showing improved tonal stability and rich harmonics.
Science, Faculty of
Physics and Astronomy, Department of
Graduate

This thesis provides a review of a computational modeling technique for woodwind-like musical instruments with arbitrarily shaped bore and finger holes. The model of a simple acoustic structure implemented in Matlab is verified through experimental measurements in terms of radiation directivity. The methods of calculating the acoustical impedance at the input end and the internal sound pressure at any position along the principle axis of the bore are presented. The procedure for calculating the radiation pressure is detailed in an example featuring a main bore with two open holes. The far-field and near-field formulas of radiation distances and angles are given. A modified pulse reflectometry system is used to measure the radiation directivity of the sample woodwind-like instrument. The measurement and data processing are simulated using a digital waveguide model to test the validity of the measurement system. The final measurements are performed with five fingerings for the measured object. The measurement results are compared with the theoretically predicted values to evaluate the fitness of the model. Suggestions for further improvement of both the measurement and the model are given.
Cette thèse propose une analyse des techniques de modélisation informatique des instruments de musique de la famille des bois à perce et trous arbitraires. Le modèle d'une structure acoustique simple implémenté avec Matlab est vérifié par des mesures expérimentales de la directivité du rayonnement. Les méthodes de calcul de l'impédance acoustique à l'entrée ainsi que de la pression acoustique à n'importe quelle position le long de l'instrument sont présentées. La procedure de calcul de la pression de radiation est détaillée pour le cas d'un tuyau cylindrique ouvert avec deux trous latéraux. Les formules de calcul du rayonnement en champ lointain et en champ proche sont données. Un système de mesure de la réponse impulsionnelle est utilisé pour mesurer la directivité de la radiation sur un prototype d'instrument ayant les caractéristiques de la famille des bois. La mesure et le traitement des données sont simulés en utilisant un modèle de guide d'ondes numérique pour tester la validité du système de mesure. Les mesures finales sont effectuées pour les cinq doigts de l'objet mesuré. Les résultats sont comparés aux valeurs théoriques pour évaluer la qualité du modèle. Des suggestions pour l'amélioration de la mesure et du modèle sont données.

Orientador: Stelamaris Rolla Bertoli
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-23T15:37:09Z (GMT). No. of bitstreams: 1 Thomazelli_Rodolfo_M.pdf: 57345196 bytes, checksum: 3da9f24b7c1ff80c9e4ffefcf62d51ed (MD5) Previous issue date: 2013
Resumo: A impedância acústica é um dos conceitos importantes para o estudo da propagação de ondas sonoras em dutos, pois por meio de sua determinação, outros parâmetros acústicos são obtidos. É um espectro em freqüências, e pode ser obtida experimentalmente através de um medidor de impedância acústica. Na presente pesquisa foi construído e validado um medidor de impedância acústica. Como objeto de estudo foi utilizados os pífanos - instrumentos de sopro da família das flautas. Dentre os métodos experimentais indicados na literatura, optou-se pelo uso do TMTC (Two Microphones Three Calibrations), devido à acessibilidade aos requisitos práticos e a possibilidade de investigação das flautas. Foram feitas medidas de impedância de dois dutos cilíndricos, de diferentes comprimentos e diâmetros internos constantes, cujos resultados foram comparados com modelos teóricos (etapa de validação). Determinou-se também a impedância acústica de três pífanos de afinações distintas. Da análise dos resultados, verificou-se a eficácia do método adotado e do aparato construído para a investigação da impedância acústica de dutos simples e, em especial, dos pífanos. Discutiu-se também aspectos importantes da construção do aparato, em termos da acessibilidade e complexidade
Abstract: The acoustical impedance is one of the indissociable factors in the studies of sound wave propagation in ducts, once its measuring provides other acoustical parameters. Its values are frequencydependent and can be determined with the use of an acoustical impedance spectrometer. For this research an acoustical impedance spectrometer was designed and validated. The research focused on a Brazilian woodwind instrument called "pífano", from the flute family. The experimental method known as TMTC (Two Microphones Three Calibrations) was chosen, for it provides easy access to practical needs and has wide capacity to interact with flutes. The spectrum from two cylindrical ducts were taken, each duct with a different length but equal inner diameters. The spectrum of three "pífanos" with different tunings, was also measured. The results from the cylindrical ducts were later compared to theoretical models (validation stage). From the results it was possible to ascertain the efficiency of the adopted method and apparatus built to investigate acoustical impedance of regular ducts and "pífano" flutes. Other important aspects of the process of building the apparatus were also discussed, in terms of accessibility and complexity
Mestrado
Arquitetura e Construção
Mestre em Engenharia Civil

The bassoon is a conical woodwind instrument blown with a double-reed mouthpiece. The sound is generated by the periodic oscillation of the mouthpiece which excites the air column. The fundamental frequency of this oscillation is determined to a large extent by the resonances of the air column. These can be varied by opening or closing tone-holes. For any given tone hole setting a fine-tuning in pitch is necessary during playing. Musicians adjust the slit opening of the double-reed by pressing their lips against the opposing reed blades. These so-called embouchure corrections are required to tune the pitch, loudness and sound color of single notes. They may be tedious, especially if successive notes require inverse corrections. However, such corrections are essential: Due to the very high frequency sensitivity of the human ear playing in tune is the paramount requirement when playing music. This implies, that embouchure actions provide an important insight into a subjective quality assessment of reed wind instruments from the viewpoint of the musician: An instrument requiring only small corrections will be comfortable to play. Theoretical investigations of the whole system of resonator, reed, and musician by use of a physical model nowadays still seem insufficient with respect to the required precision. Therefore the path of well-described artificial mouth measurements has been chosen here. For the separate treatment of the resonator and the double-reed, existing classical models have been used. Modifications to these models are suggested and verified experimentally. The influence of the musician is incorporated by the lip force-dependent initial reed slit height. For this investigation a measurement setup has been built that allows precise adjustment of lip force during playing. With measurements of the artificial mouth parameters blowing pressure, mouthpiece pressure, volume-flow rate and axial lip position on reed, the experiment is fully described for a given resonator setting represented by an input impedance curve. By use of the suggested empirical model the adjustment parameters can be turned into model parameters. A large data set from blowing experiments covering the full tonal and dynamical range on five modern German bassoons of different make is given and interpreted. The experimental data presented with this work can be a basis for extending the knowledge and understanding of the interaction of instrument, mouthpiece and player. On the one hand, they provide an objective insight into tuning aspects of the studied bassoons. On the other hand the experiments define working points of the coupled system by means of quasi-static model parameters. These may be useful to validate dynamical physical models in further studies. The experimental data provide an important prerequisite for scientific proposals of optimizations of the bassoon and other reed wind instruments. It can further serve as a fundament for the interdisciplinary communication between musicians, musical instrument makers and scientists.

A well-made flute is always a compromise and the job of flute makers is to achieve a musically and aesthetically satisfying compromise; a task that involves much trial and-error. The practical aim of this thesis is to develop a mathematical model of the flute and a computer program that assists in the flute design process. Many musical qualities of a woodwind instrument may be calculated from the acoustic impedance spectrum of the instrument. A technique for fast and accurate measurement of this quantity is developed. The technique is based on the multiple-microphone technique, and uses resonance-free impedance loads to calibrate the system and spectral shaping to improve the precision at impedance extrema. The impedance spectra of the flute and clarinet are measured over a wide range of fingerings, yielding a comprehensive and accurate database. The impedance properties of single finger holes are measured using a related technique, and fitformulae are derived for the length corrections of closed finger holes for a typical range of hole sizes and lengths. The bore surface of wooden instruments can change over time with playing and this can affect the acoustic impedance, and therefore the playing quality. Such changes in acoustic impedance are explored using wooden test pipes. To account for the effect of a typical player on flute tuning, an empirical correction is determined from the measured tuning of both modern and classical flutes as played by several professional and semi-professional players. By combining the measured impedance database with the player effects and various results in the literature a mathematical model of the input impedance of flutes is developed and implemented in command-line programs written in the software language C. A user-friendly graphical interface is created using the flute impedance model for the purposes of flute acoustical design and analysis. The program calculates the tuning and other acoustical properties for any given geometry. The program is applied to a modern flute and a classical flute. The capabilities and limitations of the software are thereby illustrated and possible contributions of the program to contemporary flute design are explored.

The bassoon is a conical woodwind instrument blown with a double-reed mouthpiece. The sound is generated by the periodic oscillation of the mouthpiece which excites the air column. The fundamental frequency of this oscillation is determined to a large extent by the resonances of the air column. These can be varied by opening or closing tone-holes. For any given tone hole setting a fine-tuning in pitch is necessary during playing. Musicians adjust the slit opening of the double-reed by pressing their lips against the opposing reed blades. These so-called embouchure corrections are required to tune the pitch, loudness and sound color of single notes. They may be tedious, especially if successive notes require inverse corrections. However, such corrections are essential: Due to the very high frequency sensitivity of the human ear playing in tune is the paramount requirement when playing music. This implies, that embouchure actions provide an important insight into a subjective quality assessment of reed wind instruments from the viewpoint of the musician: An instrument requiring only small corrections will be comfortable to play. Theoretical investigations of the whole system of resonator, reed, and musician by use of a physical model nowadays still seem insufficient with respect to the required precision. Therefore the path of well-described artificial mouth measurements has been chosen here. For the separate treatment of the resonator and the double-reed, existing classical models have been used. Modifications to these models are suggested and verified experimentally. The influence of the musician is incorporated by the lip force-dependent initial reed slit height. For this investigation a measurement setup has been built that allows precise adjustment of lip force during playing. With measurements of the artificial mouth parameters blowing pressure, mouthpiece pressure, volume-flow rate and axial lip position on reed, the experiment is fully described for a given resonator setting represented by an input impedance curve. By use of the suggested empirical model the adjustment parameters can be turned into model parameters. A large data set from blowing experiments covering the full tonal and dynamical range on five modern German bassoons of different make is given and interpreted. The experimental data presented with this work can be a basis for extending the knowledge and understanding of the interaction of instrument, mouthpiece and player. On the one hand, they provide an objective insight into tuning aspects of the studied bassoons. On the other hand the experiments define working points of the coupled system by means of quasi-static model parameters. These may be useful to validate dynamical physical models in further studies. The experimental data provide an important prerequisite for scientific proposals of optimizations of the bassoon and other reed wind instruments. It can further serve as a fundament for the interdisciplinary communication between musicians, musical instrument makers and scientists.:1 Introduction 1 1.1 Motivation 1 1.2 Scientific Approaches to Woodwind Musical Instruments 3 1.3 Organization of the Thesis 6 2 Acoustical Properties of the Bassoon Air Column 7 2.1 Wave propagation in tubes 7 2.1.1 Theory 7 2.1.2 Transmission Line Modeling 8 2.1.3 Implementation 18 2.1.4 Remarks on Modeling Wall Losses in a Conical Waveguide 19 2.2 Input Impedance Measurement 23 2.2.1 Principle 23 2.2.2 Device 23 2.2.3 Calibration and Correction 24 2.3 Comparison of Theory and Experiment 27 2.3.1 Repeatability and Measurement Uncertainty 27 2.3.2 Comparison of numerical and experimental Impedance Curves 32 2.4 Harmonicity Analysis of the Resonator 35 2.4.1 The Role of the Resonator 35 2.4.2 The reed equivalent Volume 35 2.4.3 Harmonicity Map 36 2.5 Summary 38 3 Characterization of the Double Reed Mouthpiece 41 3.1 Physical Model of the Double-Reed 41 3.1.1 Working Principle 41 3.1.2 Structural Mechanical Characteristics 42 3.1.3 Fluid Mechanical Characteristics 44 3.2 Measurement of Reed Parameters 49 3.2.1 Quasi-stationary Measurement 49 3.2.2 Dynamic Measurement 50 3.3 Construction of an Artificial Mouth 52 3.3.1 Requirements Profile 52 3.3.2 Generic Design 53 3.3.3 The artificial Lip 54 3.3.4 Air Supply 55 3.3.5 Sensors and Data Acquisition 57 3.3.6 Experimental setup 59 3.4 Summary 59 4 Modeling Realistic Embouchures with Reed Parameters 61 4.1 Reed Channel Geometry and Flow Characteristics 61 4.1.1 The Double-Reed as a Flow Duct 61 4.1.2 Bernoulli Flow-Model with Pressure Losses 65 4.1.3 Discussion of the Model 68 4.2 Quasi-static Interaction of Flow and Reed-Channel 72 4.2.1 Pressure-driven Deformation of the Duct Intake 72 4.2.2 Reed-Flow Model including Channel Deformation 75 4.2.3 Influence of Model Parameters 76 4.2.4 Experimental Verification 78 4.3 Effect of the Embouchure on the Reed-Flow 81 4.3.1 Adjustment of the Initial Slit Height 81 4.3.2 Quasi-static Flow in the Deformed Reed-Channel 83 4.3.3 Simplified empirical Model including a Lip Force 85 4.4 Summary 93 5 Survey of Performance Characteristics of the Modern German Bassoon 5.1 Experimental Procedure and Data Analysis 95 5.1.1 Description of the Experiment 95 5.1.2 Time Domain Analysis 97 5.1.3 Spectral Analysis – Period Synchronized Sampling 98 5.1.4 Spectral Centroid and Formants 99 5.1.5 Embouchure parameters 100 5.2 Observations on the Bassoon under Operating Conditions 105 5.2.1 Excitation Parameter Ranges 106 5.2.2 Characteristics of the radiated Sound 110 5.2.3 Reed Pressure Waveform Analysis 115 5.2.4 Summarizing Overview 118 5.3 Performance Control with the Embouchure 120 5.3.1 Register-dependent Embouchure Characteristics 120 5.3.2 Intonation Corrections 123 5.3.3 Sound Color Adjustments 127 5.3.4 Relation to the acoustical Properties of the Resonator 129 5.4 Summary 137 6 Conclusion 139 6.1 Summary 139 6.2 Outlook 141

The playing of a musical instrument is one of the most skilled and complex interactions between a human and an artifact. Professional musicians spend a significant part of their lives initially learning their instruments and then perfecting their skills. The production, distribution and consumption of music has been profoundly transformed by digital technology. Today music is recorded and mixed using computers, distributed through online stores and streaming services, and heard on smartphones and portable music players. Computers have also been used to synthesize new sounds, generate music, and even create sound acoustically in the field of music robotics. Despite all these advances the way musicians interact with computers has remained relatively unchanged in the last 20-30 years. Most interaction with computers in the context of music making still occurs either using the standard mouse/keyboard/screen interaction that everyone is familiar with, or using special digital musical instruments and controllers such as keyboards, synthesizers and drum machines. The string, woodwind, and brass families of instruments do not have widely available digital counterparts and in the few cases that they do the digital version is nowhere as expressive as the acoustic one. It is possible to retrofit and augment existing acoustic instruments with digital sensors in order to create what are termed hyper-instruments. These hyper-instruments allow musicians to interact naturally with their instrument as they are accustomed to, while at the same time transmitting information about what they are playing to computing systems. This approach requires significant alterations to the acoustic instrument which is something many musicians are hesitant to do. In addition, hyper-instruments are typically one of a kind research prototypes making their wider adoption practically impossible. In the past few years researchers have started exploring the use of non-invasive and minimally invasive sensing technologies that address these two limitations by allowing acoustic instruments to be used without any modifications directly as digital controllers. This enables natural human-computer interaction with all the rich and delicate control of acoustic instruments, while retaining the wide array of possibilities that digital technology can provide. In this chapter, an overview of these efforts will be provided followed by some more detailed case studies from research that has been conducted by the author's group. This natural interaction blurs the boundaries between the virtual and physical world which is something that will increasingly happen in other aspects of human-computer interaction in addition to music. It also opens up new possibilities for computer-assisted music tutoring, cyber-physical ensembles, and assistive music technologies.

The sonority is one of the definitions widely used by musicians when trying to define the color or timbral balances associated with individual or groups of instruments , such as for ensembles or orchestras. This definition obeys to subjective musical parameters associated with "color balance", "sound amplitude", among others. In the field of musical acoustics, it is well known that the sounds coming from musical instruments depend on several acoustic physical parameters such as Intensity, Frequency, and the number of harmonics, as well as other aspects including, association with its manufacturing process, such as geometry and materials used for construction. This work presents, from a spectral analysis of the timbre with the use of Fast Fourier Transform (FFT), Spectral Power Density (DPE) and Spectrograms, the characterization of the subjective concept of "sonority", for some instruments of the Woodwind family: Piccolo flute, transverse flute, clarinet and oboe. It is concluded that the stage of sound evolution as the attack and sustenance, allow the establishment of harmonics whose powers are fundamental to define the timbric "color" associated with each instrument, as well as the number of harmonics allowed to establish parameters of "sound identity", useful for the generation of a coefficient extracted from the obtained spectral analysis, which allows to advance in the characterization of the Sonority. The generalization of the method is suggested for all families of musical instruments.