<P> In acoustics, loudness is the subjective perception of sound pressure . More formally, it is defined as, "That attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud ." The relation of physical attributes of sound to perceived loudness consists of physical, physiological and psychological components . The study of apparent loudness is included in the topic of psychoacoustics and employs methods of psychophysics . </P> <P> In different industries, loudness may have different meanings and different measurement standards . Some definitions, such as ITU - R BS. 1770 refer to relative loudness of different segments of electronically reproduced sounds, such as for broadcasting and cinema . Others, such as ISO 532A (Stevens loudness, measured in sones), ISO 532B (Zwicker loudness), DIN 45631 and ASA / ANSI S3. 4, have a more general scope and are often used to characterize loudness of environmental noise . </P>

What is the meaning of loudness in science