Developing and evaluating a hybrid wind instrument

A hybrid wind instrument generates self-sustained sounds via a real-time interaction between a computed excitation model (such as the physical model of human lips interacting with a mouthpiece) and a real acoustic resonator. Attempts to produce a hybrid instrument have so far fallen short, in terms of both the accuracy and the variation in the sound produced. The principal reason for the failings of previous hybrid instruments is the actuator which, controlled by the excitation model, introduces a fluctuating component into the air flow injected into the resonator. In the present paper, the possibility of using a loudspeaker to supply the calculated excitation signal is evaluated. A theoretical study has facilitated the modeling of the loudspeaker-resonator system and the design of a feedback and feedforward filter to successfully compensate for the presence of the loudspeaker. The resulting self-sustained sounds are evaluated by a mapping of their sound descriptors to the input parameters of the physical model of the embouchure, both for sustained and attack sounds. Results are compared with simulations. The largely coherent functioning confirms the usefulness of the device in both musical and research contexts

Interaction of reed and acoustic resonator in clarinetlike systems

Sound emergence in clarinetlike instruments is investigated in terms of instability of the static regime. Various models of reed-bore coupling are considered, from the pioneering work of Wilson and Beavers ["Operating modes of the clarinet", J. Acoust. Soc. Am. 56, 653--658 (1974)] to more recent modeling including viscothermal bore losses and vena contracta at the reed inlet. The pressure threshold above which these models may oscillate as well as the frequency of oscillation at threshold are calculated. In addition to Wilson and Beavers' previous conclusions concerning the role of the reed damping in the selection of the register the instrument will play on, the influence of the reed motion induced flow is also emphasized, particularly its effect on playing frequencies, contributing to reduce discrepancies between Wilson and Beavers' experimental results and theory, despite discrepancies still remain concerning the pressure threshold. Finally, analytical approximations of the oscillating solution based on Fourier series expansion are obtained in the vicinity of the threshold of oscillation. This allows to emphasize the conditions which determine the nature of the bifurcation (direct or inverse) through which the note may emerge, with therefore important consequences on the musical playing performances

A microtonal wind controller building on Yamaha’s technology to facilitate the performance of music based on the “19-EDO” scale

We describe a project in which several collaborators adapted an existing instrument to make it capable of playing expressively in music based on the microtonal scale characterised by equal divsion of the octave into 19 tones (“19-EDO”). Our objective was not just to build this instrument, however, but also to produce a well-formed piece of music which would exploit it idiomatically, in a performance which would provide listeners with a pleasurable and satisfying musical experience. Hence, consideration of the extent and limits of the playing-techniques of the resulting instrument (a “Wind-Controller”) and of appropriate approaches to the composition of music for it were an integral part of the project from the start. Moreover, the intention was also that the piece, though grounded in the musical characteristics of the 19-EDO scale, would nevertheless have a recognisable relationship with what Dimitri Tymoczko (2010) has called the “Extended Common Practice” of the last millennium. So the article goes on to consider these matters, and to present a score of the resulting new piece, annotated with comments documenting some of the performance issues which it raises. Thus, bringing the project to fruition involved elements of composition, performance, engineering and computing, and the article describes how such an inter-disciplinary, multi-disciplinary and cross-disciplinary collaboration was co-ordinated in a unified manner to achieve the envisaged outcome. Finally, we consider why the building of microtonal instruments is such a problematic issue in a contemporary (“high-tech”) society like ours

Toward a Single Reed Mouthpiece for the Oboe

International audienceReed woodwind instruments differ in both their geometry (mainly cylindrical or mainly conical) and their excitation mechanism (single or double reed). How much of the resulting sound is due to the single/double reed, and how much to the geometry of the instrument? Measurements done by Almeida et al. (J. Acoust. Soc. Am., 121, 1, 536–546, 2007) show that the flow vs pressure characteristic curve of an oboe reed is not that different from that of a clarinet reed, the only difference probably being due to pressure recovery inside the conical staple. Is it possible to make a single reed mouthpiece for an oboe, while keeping the conical staple, that would still give the oboe its characteristic sound? To find it out, a mouthpiece with the following characteristics was made: A standard clarinet B reed can be attached to it, its volume is approximately that of the missing part of the instrument cone, and a standard French oboe staple can be inserted to it, so that it can be inserted in the usual way in any french oboe. In this paper, the first prototype of the mouthpiece is shown. Also, a sound comparison of the oboe sounds played with this mouthpiece and a standard double reed by a professional player is presented

MoReeSC: a framework for the simulation and analysis of sound production in reed and brass instruments

International audienceThis paper presents a free and open-source numerical framework for the simulation and the analysis of the sound production in reed and brass instruments. This tool is developed using the freely distributed Python language and libraries, making it available for acoustics student, engineers and researchers involved in musical acoustics. It relies on the modal expansion of the acoustic resonator (the bore of the instrument), the dynamics of the valve (the cane reed or the lips) and of the jet, to provide a compact continuous-time formulation of the sound production mechanism, modelling the bore as a series association of Helmholtz resonators. The computation of the self-sustained oscillations is controlled by time-varying parameters, including the mouth pressure and the player's embouchure, but the reed and acoustic resonator are also able to evolve during the simulation in order to allow the investigation of transient or non-stationary phenomena. Some examples are given (code is provided within the framework) to show the main features of this tool, such as the ability to handle bifurcations, like oscillation onset or change of regime, and to simulate musical effects

Idealized digital models for conical reed instruments, with focus on the internal pressure waveform

International audienceTwo models for the generation of self-oscillations of reed conical woodwinds are presented. They use the fewest parameters (of either the resonator or the ex-citer), whose influence can be quickly explored. The formulation extends iterated maps obtained for loss-less cylindrical pipes without reed dynamics. It uses spherical wave variables in idealized resonators, with one parameter more than for cylinders: the missing length of the cone. The mouthpiece volume equals that of the missing part of the cone, and is implemented as either a cylindrical pipe (first model) or a lumped element (second model). Only the first model adds a length parameter for the mouthpiece and leads to the solving of an implicit equation. For the second model, any shape of nonlinear characteristic can be directly considered. The complex characteristics impedance for spherical waves requires sampling times smaller than a round trip in the resonator. The convergence of the two models is shown when the length of the cylindrical mouthpiece tends to zero. The waveform is in semi-quantitative agreement with experiment. It is concluded that the oscillations of the positive episode of the mouthpiece pressure are related to the length of the missing part, not to the reed dynamics

PHYSMISM:a control interface for creative exploration of physical models

In this paper we describe the design and implementation ofthe PHYSMISM: an interface for exploring the possibilitiesfor improving the creative use of physical modelling soundsynthesis.The PHYSMISM is implemented in a software and hardware version. Moreover, four different physical modellingtechniques are implemented, to explore the implications ofusing and combining different techniques.In order to evaluate the creative use of physical models,a test was performed using 11 experienced musicians as testsubjects. Results show that the capability of combining thephysical models and the use of a physical interface engagedthe musicians in creative exploration of physical models

Development and Evaluation of a Hybrid Wind Instrument

A hybrid wind instrument generates self-sustained sounds via a real-time interaction between a computed excitation model (such as the physical model of human lips interacting with a mouthpiece) and a real acoustic resonator. Attempts to produce a hybrid instrument have so far fallen short, in terms of both the accuracy and the variation in the sound produced. The principal reason for the failings of previous hybrid instruments is the actuator which, controlled by the excitation model, introduces a fluctuating component into the air flow injected into the resonator. In the present thesis, the possibility of using a loudspeaker to supply the calculated excitation signal is evaluated; the loudspeaker is placed at the entrance of the resonator (a clarinet-like tube), along with a microphone. This work focusses particularly on two possibilities: using the instrument as a new musical instrument and using it as a tool to carry out wind instrument research. First, a theoretical study facilitates the modelling of the loudspeaker-resonator system and the design of a feedback and feedforward filter to successfully compensate for the presence of the loudspeaker. The prototype is then evaluated using physical models of a single-reed, a lip-reed and a bow-string interaction and using a purely mathematical “polynomial” excitation model. For the design of excitation models, the usefulness of dimensionless and reduced parameter forms is outlined, and a sound prediction theory is presented, enabling the pre-estimation of both amplitude and spectral related features of the self-sustained sounds. The resulting self-sustained sounds are evaluated by a mapping of their sound descriptors to the input parameters of the excitation models, both for sustained and attack sounds. For all excitation models, the sounds produced by the hybrid instrument are shown to match those predicted by simulation. However, the hybrid instrument is more easily destabilised for certain extreme parameter states