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  2. Decibel - Wikipedia

    en.wikipedia.org/wiki/Decibel

    The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. Until the mid-1920s, the unit for loss was miles of standard cable (MSC). 1 MSC corresponded to the loss of power over one mile (approximately 1.6 km) of standard telephone cable at a frequency of 5000 radians per second (795.8 Hz), and matched closely the smallest attenuation detectable to a ...

  3. Sound transmission class - Wikipedia

    en.wikipedia.org/wiki/Sound_transmission_class

    Sound Transmission Class (or STC) is an integer rating of how well a building partition attenuates airborne sound.In the US, it is widely used to rate interior partitions, ceilings, floors, doors, windows and exterior wall configurations.

  4. dBm - Wikipedia

    en.wikipedia.org/wiki/DBm

    The decibel (dB) is a dimensionless unit, used for quantifying the ratio between two values, such as signal-to-noise ratio. The dBm is also dimensionless, [ 1 ] [ 2 ] but since it compares to a fixed reference value, the dBm rating is an absolute one.

  5. Noise curve - Wikipedia

    en.wikipedia.org/wiki/Noise_curve

    Noise can be an annoyance that creates fatigue and negatively affects productivity, safety and the ability to communicate. Therefore, standard methodologies for quantifying noise have been developed. Noise curves reflect different standardized means of creating a single number rating for the background noise spectrum in a space.

  6. 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 ...

  7. Sound power - Wikipedia

    en.wikipedia.org/wiki/Sound_power

    Sound power or acoustic power is the rate at which sound energy is emitted, reflected, transmitted or received, per unit time. [1] It is defined [2] as "through a surface, the product of the sound pressure, and the component of the particle velocity, at a point on the surface in the direction normal to the surface, integrated over that surface."

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  9. Sound intensity - Wikipedia

    en.wikipedia.org/wiki/Sound_intensity

    1 dB = ⁠ 1 / 20 ⁠ ln(10) is the decibel. The commonly used reference sound intensity in air is [ 5 ] I 0 = 1 p W / m 2 . {\displaystyle I_{0}=1~\mathrm {pW/m^{2}} .} being approximately the lowest sound intensity hearable by an undamaged human ear under room conditions.