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Decibel: Difference between revisions
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Noise level is expressed in decibels (dB), using a logarithmic scale. A difference of 3 dB is the smallest that can be detected by the human ear, while a noise that is 10 dB louder than another is perceived to be twice as loud, although it is physically 10 times higher in pressure. An increase in noise level of 6 dB or more causes widespread annoyance and disruption. The usual measurement is in dB(A), which emphasizes the | Noise level is expressed in decibels (dB), using a logarithmic scale. A difference of 3 dB is the smallest that can be detected by the human ear, while a noise that is 10 dB louder than another is perceived to be twice as loud, although it is physically 10 times higher in pressure. An increase in noise level of 6 dB or more causes widespread annoyance and disruption. The usual measurement is in dB(A), which emphasizes the frequencies easily heard (consciously) by humans. A quiet rural night may have an ambient sound level of 20-30 dB(A). Fifteen hundred feet from an industrial wind turbine, the sound level may be 45-70 dB(A), at least four to sixteen times as loud. | ||
Another measurement is dB(C), which includes lower frequencies that are not so much heard as felt and have adverse medical and psychological effects. Lower-frequency sounds more easily penetrate walls and windows and are a significant component of wind turbine noise.<ref>https://www.wind-watch.org/documents/wind-turbine-acoustics-research-bibliography-with-selected-annotation/</ref> Yet another measurement is dB(G), which includes very-low-frequency infrasound, which recent research shows the inner ear to be sensitive to.<ref>https://www.wind-watch.org/documents/responses-of-the-ear-to-low-frequency-sounds-infrasound-and-wind-turbines/</ref> | Another measurement is dB(C), which includes lower frequencies that are not so much heard as felt and have adverse medical and psychological effects. Lower-frequency sounds more easily penetrate walls and windows and are a significant component of wind turbine noise.<ref>https://www.wind-watch.org/documents/wind-turbine-acoustics-research-bibliography-with-selected-annotation/</ref> Yet another measurement is dB(G), which includes very-low-frequency infrasound, which recent research shows the inner ear to be sensitive to.<ref>https://www.wind-watch.org/documents/responses-of-the-ear-to-low-frequency-sounds-infrasound-and-wind-turbines/</ref> | ||