Acoustics / Noise
Etymologically the word can be traced back to Old French (noyse) and to 11th century Provençal (noysa, nosa, nausa), but its origin is uncertain. It has a variety of meanings and shadings of meaning, the most important of which are the following:1. Unwanted sound: The Oxford English Dictionary contains references to noise as unwanted SOUND dating back as far as 1225.
2. Unmusical sound: The 19th century physicist Hermann von Helmholtz employed the term 'noise' to describe sound composed of non-PERIODIC vibrations (e.g. the rustling of leaves), by comparison with musical sounds, which consist of periodic vibrations. Noise is still used in this sense in expressions such as BROAD BAND NOISE, GAUSSIAN NOISE, NARROW BAND NOISE, RANDOM NOISE, RUSTLE NOISE or WHITE NOISE.
3. Any loud sound: In general usage today, noise often refers to particularly loud sounds. In this sense a noise abatement by-law prohibits certain loud sounds or establishes their permissible limits in DECIBELs. See: JET PAUSE, LOUDNESS, NOISE POLLUTION, SOUND INTRUSION, SOUND POLLUTION.
4. Disturbance in any COMMUNICATION system: In electronics and engineering, noise refers to any disturbances which do not represent part of the SIGNAL, such as static on a telephone or 'snow' on a television screen. See: BACKGROUND NOISE, SIGNAL-TO-NOISE RATIO. Compare: REDUNDANCY.
The most satisfactory definition of noise for general use is still 'unwanted sound'. This makes noise a subjective term: one person's music may be another's noise. But it also provides the opportunity for a society to come to a general agreement as to which sounds constitute unwanted intrusions.
It should be noted that each language preserves unique nuances of meaning for words representing noise. Thus in French one speaks of the bruit of a jet, but also the bruit of the birds or the bruit of the waves.
Compare: SACRED NOISE, SOUND PHOBIA, SOUNDSCAPE DESIGN. See also: ACOUSTIC TRAUMA, AMBIENCE, DAMAGE-RISK CRITERIA, HEARING LOSS, NOISE LEVEL, THRESHOLD SHIFT.