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The Basics of Noise

We talk a lot about the impacts of noise and advances in noise-controlling technologies and legislations here at NoiseNet. But what actually is noise? How is it defined by the people it affects, and by the people with the power to mitigate it? Let’s take a look at some solid definitions of noise, how and when it can affect people, and what general practices governing bodies put into place to keep it under control.

What is Noise?

Noise is sound, but when we say ‘noise’ we specifically mean ‘nuisance noise’, which is any sound that is unwanted or unpleasant. It is often defined as being harsh, sudden, repetitive, and/or prolonged. It is always loud and unignorable.

Noise is measured in ‘decibels’ (dB), which are a complex mathematical formula used to describe the amount of air pressure a particular noise carries. For reference, a normal conversation in a quiet room is around 60dB, a hair dryer is around 90dB, and a nearby ambulance siren is 120dB. This air pressure is caught by our eardrums, which vibrate to the same rhythm and intensity as the air pressure, letting us perceive the sound source. This air pressure also dissipates with distance, which is why the closer a sound is, the louder it sounds.

Where Does Noise Come From?

For the general public, most noise comes from neighbours, transport, urban development, or entertainment venues. This can be untrained barking dogs, lawn mowers and power tools, nearby train lines or souped-up cars, construction sites, or even the local pub’s open mic night.

In professional and industrial settings, noises are often more intense. Explosions, heavy machinery, moving materials, and communications equipment are commonplace. However, noise protection equipment is also more commonplace, making mitigation requirements different. When these work sites are in urban areas, those sounds are typically loud enough to impact local residents, which is a large consideration in regulations.