Post 270 – by Gautam Shah
Sound and Noise, are two irritants of space design. Both are hard to define and tackle. Clients, Designers, and subject experts, are never fully satisfied by the strategy of a solution finding or results.
In everyday life we use both the terms with different but subjective associations, though sound has more positive affiliation then what noise implies. Noise is a sound, of a type, or rather of a context. Noises are of many types, and have unclear bearing compared to sound that has specificity of quality and origin. The past associations of the perceiver are major determinants, whether a sound is considered as noise or not. Noise and sound are also differentiated on scale of aesthetic awareness. Familiarity or clearer perception can translate an aspect of noise into a sensible experience -the sound.
The term noise is derived from the Latin word nausea = sea sickness, whereas the word sound derives from soun (middle English), son (Anglo-French), sun (Latin) or sonus > sonare > sound.
Noise, even of regular composition if loud, in the short term disturbs people as it makes it difficult to hear wanted sounds, or breaks their concentration. In physics and science of acoustics, noise is an unwanted random rider to a signal, that generates hiss or static.
Noise is excessive, unpleasant, annoying and unwanted sound which results in annoyance, and in the longer term loss of hearing. Hearing impairment (presbycusis) occurs with age, but noise can hasten it. Noise causes changes in the body immune system, stress, hypertension, ischemic heart disease, tinnitus and vaso-constriction. Noise exposure also creates sleep disturbance increases workplace accidents, aggressiveness and antisocial behaviour.
‘Sound’, though desirable than Noise, can also be annoying, due to its loudness, perceptive clarity of detail, inability to localize its source, reverberations, unauthorized infiltration into protected spaces, and in substantial absence of it.
In Space Design the Noise and Sound control mechanisms overlap. Noise mitigation strategies often impact, in suppressing the desirable sounds, removing the background noises, and necessary reverberations that are often required to remove feeling of loneliness and perception of space size, form and other sensorial definitions.
The areas where noise and sound control management become important design issue are: Road, railway and aircraft corridors, cabins of transport operators, industrial plants with impact operations such as forging, transport terminals, public gathering places, underground or covered parking lots, hospitals, sanctimonious locations and buildings. Some spaces like conference halls, auditorium, meeting rooms, concert halls, entertainment and social venues, dining areas, audio recording rooms also need similar attention.
Noise and sound management techniques include: Insulation prevents transmission of noise or sound across spaces and barriers, by providing appropriate mass and surfaces. Absorption is a quality of mass to convert the sound energy into (micro level) heat within the material. Vibration damping is required to remove vibratory energy getting transmitted in thin body (sheets, tout wires) materials and thereby generate sounds. Examples are air craft and automobile bodies and very thin shell structures or roofs. It can be achieved by isolating vibratory body by including breaks or absorbent elements. Vibration causing sound waves in air, hydro-acoustic waves in water, and stresses in solid matter.
Complete sound absorption has very important roles in specialty spaces, where a sound, only from a designated source is valued. It means the perceiver, person or device, gets sound without any spatial modifications (reverberations). This is required in a recording studio, sound calibration labs, and non detectable stealth vehicles like air-crafts or submarines.
The traditional sound and noise handling techniques are based on materials sciences, shape or form configurations, and element siting. These traditional methods required extensive interventions in space, such as partitions, ceilings, floor treatments. These elements use absorbent or insulation materials and techniques that are highly vulnerable to fire and have high ecological concerns. The sound and noise control elements reduced the daylight into deeper spaces and reduced the outdoor viewing. For a unified space configuration, reduction of barricading and intervening elements is very important, which can occur by adopting sound masking technologies.
Sound masking is opposite of soundproofing, as it is an active addition of noise to a space, to counter certain sounds. It is like in an Interior Space where to reduce the glare from an opening, one can either place a curtain on the opening, or put on additional illumination in the room. Sound insulation works like the former and sound masking like the later method.
Sound masking is addition of natural or artificial sound into a space to suppress the effects of unwanted sound. It is done with specially designed speakers installation to add ‘low level’ sounds over the existing sounds in the space. It reduces the chances of imperceptible sounds coming to a personal field, and affect the concentration or add to distraction. Additional sounds reduce or eliminate the pervading feeling of pre-existing sounds to make living areas more audio-comfortable.