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  2. Sound pressure - Wikipedia

    en.wikipedia.org/wiki/Sound_pressure

    While 1 atm (194 dB peak or 191 dB SPL) [11] [12] is the largest pressure variation an undistorted sound wave can have in Earth's atmosphere (i. e., if the thermodynamic properties of the air are disregarded; in reality, the sound waves become progressively non-linear starting over 150 dB), larger sound waves can be present in other atmospheres ...

  3. A-weighting - Wikipedia

    en.wikipedia.org/wiki/A-weighting

    A graph of the A-, B-, C- and D-weightings across the frequency range 10 Hz – 20 kHz Video illustrating A-weighting by analyzing a sine sweep (contains audio). A-weighting is a form of frequency weighting and the most commonly used of a family of curves defined in the International standard IEC 61672:2003 and various national standards relating to the measurement of sound pressure level. [1]

  4. Decibel - Wikipedia

    en.wikipedia.org/wiki/Decibel

    where p rms is the root mean square of the measured sound pressure and p ref is the standard reference sound pressure of 20 micropascals in air or 1 micropascal in water. [ 34 ] Use of the decibel in underwater acoustics leads to confusion, in part because of this difference in reference value.

  5. Sound exposure - Wikipedia

    en.wikipedia.org/wiki/Sound_exposure

    The commonly used reference sound exposure in air is [2] E 0 = 400 μ P a 2 ⋅ s . {\displaystyle E_{0}=400~\mathrm {\mu Pa^{2}\cdot s} .} The proper notations for sound exposure level using this reference are L W /(400 μPa 2 ⋅s) or L W (re 400 μPa 2 ⋅s) , but the notations dB SEL , dB(SEL) , dBSEL, or dB SEL are very common, even if ...

  6. Weighting filter - Wikipedia

    en.wikipedia.org/wiki/Weighting_filter

    Sound has three basic components, the wavelength, frequency, and speed. In sound measurement, we measure the loudness of the sound in decibels (dB). Decibels are logarithmic with 0 dB as the reference. [1] There are also a range of frequencies that sounds can have. Frequency is the number of times a sine wave repeats itself in a second. [2]

  7. Hearing conservation program - Wikipedia

    en.wikipedia.org/wiki/Hearing_conservation_program

    The action level for enrollment in a hearing conservation program is 85 dBA 8-hour TWA, integrating all sound levels between 80 dBA to at least 130 dBA. MSHA uses a 5-dB exchange rate (the sound level in decibels that would result in halving [if an increase in sound level] or a doubling [if a decrease.in sound level] the allowable exposure time ...

  8. Anechoic chamber - Wikipedia

    en.wikipedia.org/wiki/Anechoic_chamber

    In 2005, the best anechoic chamber measured at −9.4 dBA. [2] In 2015, an anechoic chamber on the campus of Microsoft broke the world record with a measurement of −20.6 dBA. [3] The human ear can typically detect sounds above 0 dBA, so a human in such a chamber would perceive the surroundings as devoid of sound.

  9. Sound reduction index - Wikipedia

    en.wikipedia.org/wiki/Sound_Reduction_Index

    The Sound Reduction Index is expressed in decibels (dB). It is the weighted sound reduction index for a partition or single component only. This is a laboratory-only measurement, which uses knowledge of the relative sizes of the rooms in the test suite, and the reverberation time in the receiving room, and the known level of noise which can pass between the rooms in the suite by other routes ...