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Level (decibel, dB |
| A unit used in acoustics in the measurement of physical quantites. It is 10 times of logarithn of the ratio of two variables, the denominator is usually the reference value of the physical quantity, which are related to power in some manner. The most common terms are sound pressure level, sound level and sound power level. |
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Loudness level (phons |
| A logarithmic scale of loudness where a doubling of halving of loudness represents a 3 phon change in loudness level. |
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Loudness (sones) |
| A subjective attribute of sound. A doubling or halving of loudness represents a change of about 10 decibels. The loudness of a sound depends on its sound pressure level and its frequency content. |
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