Title: Sone
Content: direct field or free field) or R (for room field or diffuse field). Sone The sone () is a unit of loudness, how loud a sound is perceived. Doubling the perceived loudness doubles the sone value. Proposed by Stanley Smith Stevens in 1936, it is not an SI unit. In acoustics, loudness is the subjective perception of sound pressure. The study of apparent loudness is included in the topic of psychoacoustics and employs methods of psychophysics. According to Stevens' definition, a loudness of 1 sone is equivalent to the loudness of a signal at 40 phons, the "loudness level" of

Title: Loudness
Content: shows that humans with normal hearing are most sensitive to sounds around 2–4 kHz, with sensitivity declining to either side of this region. A complete model of the perception of loudness will include the integration of SPL by frequency. Historically, loudness was measured using an "ear-balance" audiometer in which the amplitude of a sine wave was adjusted by the user to equal the perceived loudness of the sound being evaluated. Contemporary standards for measurement of loudness are based on summation of energy in critical bands. When sensorineural hearing loss (damage to the cochlea or in the brain) is present, the

Title: Psychoacoustics
Content: Equal-loudness contours were first measured by Fletcher and Munson at Bell Labs in 1933 using pure tones reproduced via headphones, and the data they collected are called Fletcher–Munson curves. Because subjective loudness was difficult to measure, the Fletcher–Munson curves were averaged over many subjects. Robinson and Dadson refined the process in 1956 to obtain a new set of equal-loudness curves for a frontal sound source measured in an anechoic chamber. The Robinson-Dadson curves were standardized as ISO 226 in 1986. In 2003, was revised as equal-loudness contour using data collected from 12 international studies. Sound localization is the process of

Title: Equal-loudness contour
Content: Equal-loudness contour An equal-loudness contour is a measure of sound pressure (dB SPL), over the frequency spectrum, for which a listener perceives a constant loudness when presented with pure steady tones. The unit of measurement for loudness levels is the phon, and is arrived at by reference to equal-loudness contours. By definition, two sine waves of differing frequencies are said to have equal-loudness level measured in phons if they are perceived as equally loud by the average young person without significant hearing impairment. Equal-loudness contours are often referred to as "Fletcher-Munson" curves, after the earliest researchers, but those studies have

Title: Loudness
Content: levels. Loudness normalization is a specific type of audio normalization that equalizes perceived level such that, for instance, commercials do not sound louder than television programs. Loudness normalization schemes exist for a number of audio applications. Historically Sone (loudness "N") and Phon (loudness level "L") units have been used to measure loudness. A-weighting follows human sensitivity to sound and describes relative perceived loudness for at quiet to moderate speech levels, around 40 phons. Relative loudness monitoring in production is measured in accordance with ITU-R BS.1770 in units of LKFS. Work began on ITU-R BS.1770 in 2001 after 0 dBFS+ level

Question: Which scientific unit gives a measure of loudness?
Answer: Decibel