Architectural Acoustics

The third most common complaint of defects in buildings is noise. Architectural acoustics is the study of applying sound control within and between buildings. An early well recorded application of architectural acoustics is in opera house design. More recently it has been applied to both new and renovated concert halls. This has much to do with the quality of sound rather than noise suppression which is critical to the design of multi-occupancy building and city centre living. Dwellings and business premises may both generate significant noise and suffer from noise intrusion. The design of workplaces has often to contend with the potential effects of noise on health. Architectural acoustics includes room acoustics, the design of recording and broadcast studios, home theaters, and listening rooms for media playback. Noise propagation The main noise paths into and out of buildings are often found to be where the building envelope is interrupted and through light weight elements, typically roofs, eaves, walls, windows, doors and service penetrations. Sufficient control ensures space functionality and is often required based on building use and local municipal codes. An example would be providing a suitable design for a home which is to be constructed close to a high volume roadway, or under the flight path of a major airport, or of the airport itself. Controlling noise transmission between rooms to ensure privacy and comfort is often poorly served by modern fast track construction. Sound transmission may conveniently be categorized as direct and flanking. The typical direct sound paths are through light weight room partitions, floors and ceilings. Poorly fitting, open or badly sealed doors, windows, service ducts and even small holes can greatly impair sound attenuation between rooms. Room acoustics This is the science of influencing the quality of sound in a room by controlling room dimensions and the characteristics of exposed surfaces. The sound absorbing and reflecting properties of exposed surfaces can modify reverberation time and tonal quality. Within closed spaces sound reflections can create standing waves that produce natural resonances that can be heard as a pleasant sensation or an annoying one. Angling the room boundaries so that they diverge from one another at an angle of 7o or more tends to control the strong resonant effect that standing waves often cause. Reflective surfaces can be angled and coordinated to provide good coverage of sound for a listener in a concert hall or music recital space. Interior building surfaces can be constructed of many different materials and finishes. One way to adjust room acoustics at need is by altering the way the room is furnished and the reflective properties of the bounding surfaces. Another method, often used in open plan offices is the deliberate introduction of pink noise. This can often improve speech privacy at low cost but is best used as a part of an overall strategy