ACOUSTICS

As Charles Garnier prepared the design for the Paris Opera House in 1861, the lack of
acoustical design information and the contradictory nature of the information that he
found forced him to leave the acoustic quality to chance and hope for the best. With few
exceptions, this was the condition of architectural acoustics at the beginning of the 20th
century. In 1900, with the pioneering work of Wallace Clement Sabine, the dark
mysteries of “good acoustics” began to be illuminated. In his efforts to remedy the poor
acoustics in the Fogg Art Museum Lecture Hall (1895–1973) at Harvard University,
Entries A–F 19
Sabine began experiments that revealed the relationship among the architectural materials
of a space, the physical volume of the space, and the time that sound would persist in the
space after a source was stopped (the reverberation time). Predicting the reverberation
time of a room provided the first scientific foundation for reliable acoustic design in
architecture. This method is still regularly used as a benchmark to design a range of
listening environments, from concert halls to school classrooms.
The first application of this new acoustical knowledge occurred during the design of
the Boston Symphony Hall (1906) by McKim, Mead and White. Original plans for the
hall called for an enlarged version of the Leipzig Neues Gewandhaus (1884), a classical
Greek Revival theater. The increased size would have been acoustically inappropriate, as
it doubled the room volume, leading to excessive reverberation. Sabine worked with the
architects to develop a scheme with a smaller room volume in the traditional “shoe box”
concert hall shape. The Boston Symphony Hall remains one of the best in the world.
Adler and Sullivan’s Auditorium Building (1889) in Chicago was praised for its
architectural and engineering achievements as well as for the theater’s superb acoustics.
As the profession of acoustical consulting emerged in the design of listening spaces, the
firm of Bolt, Beranek and Newman made a significant impact on the development of
architectural acoustics in the 20th century. Their work with architects Harrison and
Abramovitz on Avery Fisher Hall (1962) in New York City represented a legitimate
attempt to incorporate new scientific principles of acoustical design rather than merely
copying previous halls that were known to be good. Although it presented several
failures, one key acoustic point gleaned from a study of European halls for Avery Fisher
Hall was that the room should hold 1,400 to 1,800 seats. Yielding to economic pressures,
the architect increased seating to almost 3,000.
A more successful implementation of modern acoustical theories is the Berlin
Philharmonic (1963). Architect Hans Scharoun’s vision of a hall in the round blurs the
traditional distinction between performer and audience. The approach posed quite an
acoustical challenge, given the directionality of many orchestral instruments; it required
an extremely unconventional acoustical design. The resulting “vineyard terrace” seating
arrangement resolved many potential acoustical difficulties while creating a spatial
vitality that resonates outward to form the profile of the building. This collaboration
between Scharoun and the acoustic consultant Lothar Cremer engendered a truly inspired
architectural design.
Possibly inspired by the failure of Avery Fisher Hall and the desire to understand what
went wrong, concert halls, as the crucible for applying sonic theories, gave rise to an
acoustical renaissance in the latter part of the 20th century. Acoustically designed spaces
need high-quality direct sound, strong sound reflections from the ceiling and side wall
surfaces soon after the direct sound, a highly diffuse and controlled reverberance, and
heavy solid sound reflecting materials. Formerly thought to be mutually exclusive, these
sonic properties exist together in the latest halls of the 20th century through an integration
of both historic precedent and new understandings of room acoustics and listening. An
extraordinary example of this union is the 1,840-seat Concert Hall in the Cultural
Congress Center (1999) in Lucerne, Switzerland, by architect Jean Nouvel and acoustic
consultant Russell Johnson.
New techniques for improved acoustic environments are applied in many building
types, including school classrooms, music practice rooms, church sanctuaries, movie
Encyclopedia of 20th-century architecture 20
theaters, transportation hubs, and industrial facilities. Simultaneously, with more and
more exposure to digital-quality sound, clients have become keenly aware of their sonic
environment and expect high levels of performance. Speech intelligibility in classrooms
has been related to learning, with efforts to reduce excessive background noise from
mechanical equipment. The issue has become the focus of a U.S. federal government
assessment and proposal for a nationwide acoustical standard for schools. Additionally,
careful selection of materials, their quantities, and their locations in classrooms are
important to enhance speech intelligibility. Music practice spaces require adequate room
volume with both soundabsorbent and sound-diffusing materials to control loudness and
reduce the risk of noise-induced hearing loss to musicians and teachers. Religious liturgy
relies more heavily on intimate spoken sermons, cathedral-like choir singing, and highpowered
amplified music in many denominations. These trends, coupled with a
prevailing increase in sanctuary size and the desire for more congregational interaction,
have demanded sophisticated sound reinforcement systems and carefully configured
room acoustic design strategies to strike a balance among divergent sonic criteria. Digital
surround sound, the new standard in movie theater entertainment, incorporates the
environmental acoustic character as part of the movie sound track, which should not be
colored by the theater space. This requires very low reverberance, low background noise
levels from mechanical equipment, and exceptional sound isolation from adjacent
theaters. Unintelligible announcements, the bane of transportation hubs, have been the
focus of many recent acoustical studies, affirming the need to consider room geometry,
size, and material selection as they play as great a role as the actual announcement system
itself in the success of these spaces.
Many meaningful advances in acoustic knowledge were made in the 20th century. The
application and integration of this information within architectural design leaves much
room for advancement. Alvar Aalto’s famous acoustical ray tracing diagrams for the
lecture room of the Viipuri Public Library (1933–35) in Viipuri, Finland, represent
acoustical thinking in the earliest phases of design. Developing sophisticated methods to
assimilate newer acoustical knowledge as part of the architectural design process is the
work at hand in the 21st century.