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  2. Sound transmission class - Wikipedia

    en.wikipedia.org/wiki/Sound_transmission_class

    The STC or sound transmission class is a single number method of rating how well wall partitions reduce sound transmission. [3] The STC provides a standardized way to compare products such as doors and windows made by competing manufacturers. A higher number indicates more effective sound insulation than a lower number.

  3. 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 ...

  4. 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]

  5. 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 ...

  6. Audio system measurements - Wikipedia

    en.wikipedia.org/wiki/Audio_system_measurements

    Cassette noise, which was predominately high frequency and unavoidable given the small size and speed of the recorded track could be made subjectively much less important. The noise sounded 10 dB quieter, but failed to measure much better unless 468-weighting was used rather than A-weighting.

  7. Noise reduction coefficient - Wikipedia

    en.wikipedia.org/wiki/Noise_reduction_coefficient

    The noise reduction coefficient is "a single-number rating, rounded to the nearest 0.05, of the sound absorption coefficients of a material for the four one-third octave bands at 250 Hz, 500 Hz, 1000 Hz and 2000 Hz". [4]

  8. Sound exposure - Wikipedia

    en.wikipedia.org/wiki/Sound_exposure

    E is the sound exposure; E 0 is the reference sound exposure; 1 Np = 1 is the neper; 1 B = ⁠ 1 / 2 ⁠ ln 10 is the bel; 1 dB = ⁠ 1 / 20 ⁠ ln 10 is the decibel. The commonly used reference sound exposure in air is [2] = .

  9. Audio power - Wikipedia

    en.wikipedia.org/wiki/Audio_power

    Many high-quality domestic speakers have a sensitivity between ~84 dB and ~94 dB, but professional speakers can have a sensitivity between ~90 dB and ~100 dB. An '84 dB' source would require a 400-watt amplifier to produce the same acoustical power (perceived loudness) as a '90 dB' source being driven by a 100-watt amplifier, or a '100 dB ...