Sone
From Wikipedia, the free encyclopedia
The sone is a unit of perceived loudness N after a proposal of S. Smith Stevens in 1936. In acoustics, loudness is a subjective measure of the sound pressure. At a frequency of 1 kHz, 1 phon is defined to be equal to 1 dB of sound pressure level Lp above the nominal threshold of hearing, the sound pressure level SPL of 20 µPa (micropascals) = 2 × 10-5 pascal (Pa).
One sone is equivalent to 40 phons, which is defined as the loudness level NL of a 1 kHz tone at 40 dB SPL. The number of sones to a phon was chosen so that a doubling of the number of sones sounds to the human ear like a doubling of the loudness, which also corresponds to increasing the sound pressure level by 10 dB, or increasing the sound pressure by a factor 3.16 =
. At frequencies other than 1 kHz, the measurement in sones must be calibrated according to the frequency response of human hearing, which is of course a subjective process. The study of apparent loudness is included in the topic of psychoacoustics.
To be fully precise, a measurement in sones must be qualified by the optional suffix G, which means that the loudness value is calculated from frequency groups, and by one of the two suffixes F (for free field) or D (for diffuse field).
[edit] Examples of sound pressure, sound pressure levels, and loudness in sone
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Source of sound sound pressure sound pressure level loudness pascal dB re 20 µPa sone threshold of pain 100 134 ~ 676 hearing damage during short-term effect 20 approx. 120 ~ 250 jet, 100 m distant 6 - 200 110 - 140 ~ 125 - 1024 jack hammer, 1 m distant / discotheque 2 approx. 100 ~ 60 hearing damage during long-term effect 6×10−1 approx. 90 ~ 32 major road, 10 m distant 2×10−1 - 6×10−1 80 - 90 ~ 16 - 32 passenger car, 10 m distant 2×10−2 - 2×10−1 60 - 80 ~ 4 - 16 TV set at home level, 1 m distant 2×10−2 ca. 60 ~ 4 normal talking, 1 m distant 2×10−3 - 2×10−2 40 - 60 ~ 1 - 4 very calm room 2×10−4 - 6×10−4 20 - 30 ~ 0.15 - 0.4 leaves' noise, calm breathing 6×10−5 10 ~ 0.02 auditory threshold at 2 kHz 2×10−5 0 0
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sone 1 2 4 8 16 32 64 phon 40 50 60 70 80 90 100
