The day-night average sound level (Ldn or DNL) is the average noise level over a 24-hour period. The noise between the hours of 10pm and 7am is artificially increased by 10 dB. This noise is weighted to take into account the decrease in community background noise of 10dB during this period.
The Federal Aviation Administration has established this measure as a community noise exposure metric to aid airport noise analyses under Federal Aviation Regulation Part 150.
Famous quotes containing the words average, sound and/or level:
“One cannot develop taste from what is of average quality but only from the very best.”
—Johann Wolfgang Von Goethe (1749–1832)
“A person is far more likely to appear to have sound character because he persistently follows his temperament than because he persistently follows his principles.”
—Friedrich Nietzsche (1844–1900)
“Why level downward to our dullest perception always, and praise that as common sense? The commonest sense is the sense of men asleep, which they express by snoring.”
—Henry David Thoreau (1817–1862)