Architectural acoustics of concert halls : acoustics and design of modern halls for music

Architectural acoustics is that branch of science that studies the acoustics and the design of sites for music. Due to the subjectivity of its nature, this discipline is today still considered as much as a science as a from of art. As suggested by the, architectural acoustics comprises two different fields of study: acoustics and architecture. This work considers only the acoustical half of the topic and the role of the acoustician that, for the successful completion of a project, must work in team with the architect: esthetics needs to be combined with acoustically favourable shapes because, ultimately, music venues are created to perform. One of the purposes of this thesis is also to introduce readers that are not familiar with the subject, to the complex field of architectural acoustics. Starting from the basic sound principles/concepts and arriving to the psychoacoustical understanding of the human auditory systems, the reader is provided with the basis to understand how sound propagates and interacts in indoor environments. This work deals with the in-depth analysis of the acoustics of concert halls that are performance venues constructed specifically for instrumental classical music in which music is performed exploiting the natural properties of the room without the use of any electroacoustical devices. However, as of today, concert halls around the world need to adapt to new music, to a new culture, to a new generation and to the different needs of the audiences. As a consequence the modern music sites introduce new different elements that were not present in traditional halls, such as the occasional use of loudspeakers, new shapes and designs for arranging the audiences and also the application of the new technologies in the realization and use of these structures, that allow them, in the latter case, to adapt their acoustics depending on the type of performance. The core of this work is to analyze the acoustics of concert halls, from their origins in the past up to the present, and in particular the acoustics of the modern halls. What volume is required? How should the room be shaped? What is the necessary reverberation time? How should absorption and reflecting surfaces be placed? These are just a few examples of questions whose answers can be found in this work. In addition, the acoustical noise control of the buildings, the new methodologies for variable acoustics including the modern use of electronic architecture for virtually changing the acoustics of a room are explained. There are also chapters and sections dedicated to the subjective/objective parameters for constructing and evaluating concert halls and how the acoustical design of a hall can be tested prior to its construction by means of computer or acoustic scale models. Besides the examples found throughout the text, at the end of this work four cases of study, that respectively consider four different modern halls around the world, demonstrate the application of all the theoretical concepts studied through this thesis, each one highlighting different characteristics, providing practical and real examples on the acoustical features and on the new design and methodologies used for obtain the superb acoustics of modern concert halls.