Editing Noise (section)

== Measurement ==
[[File:Photo The urban police of Milan while using a noise measurement device for sound level control on city streets 1955 - Touring Club Italiano 07 0626.jpg|thumb|upright|The urban police of Milan while using a noise measurement device for sound level control on city streets in 1955]]
Sound is measured based on the [[amplitude]] and [[frequency]] of a sound wave. Amplitude measures how forceful the wave is. The energy in a sound wave is measured in [[Decibel|decibels (dB)]], the measure of [[loudness]], or [[Intensity (physics)|intensity]] of a sound; this measurement describes the amplitude of a sound wave. Decibels are expressed in a [[logarithmic scale]]. On the other hand, pitch describes the frequency of a sound and is measured in [[Hertz|hertz (Hz)]].<ref>{{Cite web|url=http://sciencelearn.org.nz/Contexts/The-Noisy-Reef/Science-Ideas-and-Concepts/Measuring-sound|title=Measuring sound|website=Sciencelearn Hub|access-date=2016-06-20|archive-date=2016-12-31|archive-url=https://web.archive.org/web/20161231180252/http://sciencelearn.org.nz/Contexts/The-Noisy-Reef/Science-Ideas-and-Concepts/Measuring-sound|url-status=dead}}</ref>

The main instrument to measure sounds in the air is the [[Sound level meter|Sound Level Meter]]. There are many different varieties of instruments that are used to measure noise - [[Noise dosimeter|Noise Dosimeters]] are often used in occupational environments, noise monitors are used to measure [[environmental noise]] and [[noise pollution]],  and recently [[smartphone]]-based sound level meter applications (apps)<ref>{{Cite web|url=https://blogs.cdc.gov/niosh-science-blog/2014/04/09/sound-apps/|title=So How Accurate Are These Smartphone Sound Measurement Apps? {{!}} {{!}} Blogs {{!}} CDC|website=blogs.cdc.gov|date=9 April 2014 |language=en-us|access-date=2018-06-15}}</ref> are being used to crowdsource and map recreational and community noise.<ref>{{Cite news|url=http://noiseandthecity.org/noisescore/|title=NoiseScore: A Free Smartphone App for Community Noise Issues With Live Map|work=Noiseandthecity.org|access-date=2018-06-15|language=en-US|archive-date=2018-06-16|archive-url=https://web.archive.org/web/20180616001925/http://noiseandthecity.org/noisescore/|url-status=dead}}</ref><ref>{{Cite web|url=https://www.soundprint.co/|title=soundprint – Find Your Quiet Place|website=www.soundprint.co|language=en-US|access-date=2018-06-15}}</ref><ref>{{Cite web|url=http://www.ihearu.co/|title=iHEARu|website=www.ihearu.co|language=en|access-date=2018-06-15}}</ref>

[[A-weighting]] is applied to a sound spectrum to represent the sound that humans are capable of hearing at each frequency. Sound pressure is thus expressed in terms of dBA. 0 dBA is the softest level that a person can hear. Normal speaking voices are around 65 dBA. A rock concert can be about 120 dBA.