Numerical Techniques for Acoustic Modelling and Design of Brass Wind Instruments

Preface. When H. Bouasse published his Instrumentsà Vent in two volumes in 1929–30, he set the starting point for what can be regarded as modern research on musical acoustics. Some 40 years later, the stock of published papers could be counted in their hundreds. However, it is only during the last two or three decades that our physical understanding, in combination with the development of computers, has made it possible to analyse wind instruments with the precision necessary, not only to explain the basic principles of their function, but also to be of practical use for instrument makers. This thesis deals with numerical methods and procedures for the analysis and design of acoustic horns of the kind found in brass instruments. The same models are applicable also to loudspeaker horns, with which one part of the thesis is concerned. Although the properties and merits of different systems for sound reproduction , such as loudspeakers, are sometimes debated lively, it is at least possible to define an ideal system, in the sense that the sound at the position of the listener's ears should be in as good agreement as possible with the sound at the position of the microphone in the concert hall during the recording. When speaking about optimisation of musical instruments, one has to be much more careful. The instruments of the modern western orchestra are the result of centuries of evolution, where tradition, musical ideals, performance techniques , and acoustical considerations have been inextricably intertwined with each other. Our judgement about a certain instrument is dependent on a pre-conception about how the instrument should sound [13], and this preconception may vary between individuals, different musical settings and different times. It is important to bear in mind that the term " quality " for the sound of a musical instrument lacks sense, unless one also places the instrument in its musical context. Nevertheless, research on musical acoustics is of more than constructional interest. Firstly, it gives the possibility to quantify the differences between instruments , and to answer the question why one instrument is considered to be better than another. Secondly, once we have a clear-cut idea about what we expect from an instrument, we can apply the mathematical tools in order to make instruments that comply with our standards as far as possible. 1. Introduction. Inasmuch as one can only judge what is the most agreeable of the …