"We shape our buildings, and afterward our buildings shape us." - Winston Churchill, 1943
p.1 "Architecture, which has been called the "mother of all arts," is concerned with the design, arrangement, and manipulation of the physical properties of a space. Unlike other art forms, architecture provides spaces for the daily activities of life; when more the simply utilitarian, it also appeals to our aesthetic sensibilities. By choosing and combining materials, colors and shapes, architects embed their respective artistic messages in structures that we see, hear, and feel. Like poets with their specialized language, architects communicate their worldview with a vocabulary of spatial elements that often contain symbolic meaning reflecting their culture."
p. 2 "The composite of numerous surfaces, objects, and geometries in a complicated environment creates an aural architecture. As we hear how sounds from multiple sources interact with the various spatial elements, we assign an identifiable personality to the aural architecture, in much the same way we interpret an echo as the aural personality of a wall. ... In addition to providing acoustic cues that can be interpreted as objects and surfaces, aural architecture can also influence our moods and associations. Although we may not be consciously aware that aural architecture is itself a sensory stimulus, we react to it."
p. 3 "Aural architecture, with its own beauty, aesthetic, and symbolism, parallels visual architecture. Visual and aural meanings often align and reinforce each other. ... Since listening with understanding depends on culture, rather than on biology of hearing, auditory spatial awareness must be considered the province of sensory anthropology. To evaluate aural architecture in its cultural context, we must ascertain how acoustic attributes are perceived: by whim, under what conditions, for what purposes, and with what meanings. Understanding aural architecture requires an acceptance of the cultural relativism for all sensory experiences."
p. 4 "Aural architecture refers to the properties of a space that can be experienced by listening. An aural architect, acting as both an artist and social engineer, is therefore someone who selects specific aural attribute of a space based on what is desirable in a particular cultural framework. ... In describing the aural attributes of a space, an aural architect uses a language, sometimes ambiguous, derived from the values, concepts, symbols, and vocabulary of a particular culture. ... Because of differences in their perspectives, acoustic architects focus n the way that the space changes the physical properties of sound waves (spatial acoustics), whereas the aural architect focus on the way that listeners experience the space (cultural acoustics)."
p. 5 "Even though aural architecture shares the same intellectual foundation, its language and literature are sparse, fragmented, and embryonic. ... There are four principle reasons why this might be so. First, aural experiences of space are fleeting, and we lack the means for storing their cultural and intellectual legacy in museums, journals, and archives. Second, for both cultural and biological reasons, the language for describing sound is weak and inadequate. Third, being fundamentally oriented toward visual communications, modern culture has little appreication for the emotional importance of hearing, and thus attaches little value to the art of aufditory spatial awareness. And fourth, questions about aural architecture are not generally recognized as a legitimate domain for intellectual inquiry; professional schools provide little or no training in physical acoustics, aural aesthetics, or sensory sociology."
"Architecture begins where engineering ends." - Walter Gropius
"Architecture is to make us know and remember who we are." - Geoffrey Jellicoe, 1989
p. 362 "In contrast with preliterate societies, however, our modern technological society tends to devalue hearing, smell, taste, and touch, preferring sight as the principle means for sensing the environment. Traditionally, we therefore both create and experience architecture visually, rather than with all our senses. ... As modern humans living an familiar spaces with omnipresent illumination, most of us can see little use in having auditory spatial awareness. But should the lights fail, the need to navigate or orient in a space by listening will remind us of how useful it is to sense space without vision. Similarly, we sometimes "feel" someone approaching from behind even when that someone is silent. ... As a culture, we can create social and architectural opportunities to encourage our fellow citizens, especially our children, to acquire spatial awareness. When many of us attend that have a complex and socially desirable aural architecture. In turn, a rich aural architecture is more likely to stimulate development of that auditory spatial awareness.
Sound and Structural Vibration: Radiation, Transmission and Response - Frank Fahy
p. 27 "Natural Frequencies and Modes of Vibration. Although all of these wave phenomena may occur in solid structures, the one having most practical importance is reflection. The reason for its importance is that it is responsible for the existence of sets of frequencies, and associated spatial patterns of vibration, which are proper to a bounded system. An infinitely long beam can vibrate freely only at particular natural or characteristic frequencies. The elements of the beams which are not at boundaries satisfy the same equation of motion in both cases; they clearly only "know about" the boundaries because of the phenomenon of wave propagation and reflection. Wave reflection at boundaries also leads to the vary important phenomenon of resonance. Note carefully that resonance is a phenomenon associated with forced vibration, generated by some input, whereas natural frequencies are phenomena of free vibration. Resonance is of great practical importance because it involves large amplitude response to excitation, and can lead to structural failure, system malfunction, and other undesirable consequences."
p. 217 Acoustically Induced Vibration of Structures
"Any solid structure exposed to a sound field in a contiguous fluid medium will respond to some degree to the fluctuating pressures acting at the interface between the two media. It is common experience that heavy road traffic can produce visually observable low-frequency displacements in window panes of houses adjacent to a highway; heavy rock devotees love the body vibrations induced by the very high powered loudspeaker systems used by performing groups.
The process of transmission of airborne sound energy through partitions involved vibrational response to sound pressures acting on one side, together with the consequent radiation of sound from the other side. This process, generally involves extremely small transverse displacement amplitudes of the partitions, which therefore do not constitute a threat to the integrity of the structures. There are, however, cases of considerable practical significance in which acoustically induced vibrations levels are of such a magnitude as to require the engineer to assess the likely effects on the structural and operational integrity of the system concerned. Acoustically induced fatigue failure first came to prominence in the 1950s owing to the high levels of jet noise to which aircraft structures were exposed; in the 1960s aerospace engineers became concerned with the high levels of vibration induced in spacecraft structures and on-board equipment packages due to rocket noise at launch; and acoustically induced fatigue failure of nuclear reactor and industrial plant components came to light at about the same time.
Other examples of acoustically induced vibration of practical significance include the degradation of receiving sonar array performance by the response if the surrounding hull structure to the incoming sound field; low-frequency, airborne sound-induced vibration of complete building structures by sources such as large reciprocating compressors; vibration of the tank tops (engine support structures) of ships by airborne noise radiated by the underside of the engines; and the process of absorption of sound by structures in buildings, such as lightweight ceilings, glazing, and panelling. The mechanisms of structural vibration caused by explosive blasts and by sonic booms are qualitatively similar, but these airborne disturbances differ from those considered in this book because they are finite amplitude and are therefore non-linear in nature. "
P. 241 Acoustic Coupling between Structures and Enclosed Volumes of Fluid
"The most significant difference between the acoustic behavior of fluid contained within physical boundaries and that of unconstrained fluid is the existence in the former of natural modes of vibration and associated natural frequencies; these are called acoustic modes. As in solid structures, acoustic modes arise fro interference between intersecting wave, and the natural frequencies are associated with the correspondence between the spatial characteristics of the interference pattern and the geometry of the physical boundaries of the fluid volume. An enclosed fluid exhibits resonant acoustic behavior, the effects of which are to produce a strongly frequency-dependent response to vibration by contiguous structures, together with fluid-loading effects that also exhibit strong dependence upon frequency. Practical examples of interest include machinery noise control enclosures, double-leaf partitions, vehicle cabin spaces, tympanic and bodied musical instruments, loudspeaker enclosures, and fluid transport ducts. The skin drum is an example of a system in which solid-fluid interaction is fundamental to its vibrational behavior."
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