Types of Noise

When categorizing noise, there are generally four main types: continuous, intermittent, impulsive, and low-frequency. The main differentiating factor between these types is how the noise changes with time.

Let’s now discuss in detail the different types of noise that surround us all.

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Continuous Noise

As is obvious by the name, continuous noise is the noise that remains stable and constant over a given period. For instance, machinery that operates without interruption produces continuous noise.

Examples can include:

• a vacuum cleaner
• boilers in a powerhouse
• factory equipment
• sound of an engine
• heating and ventilation systems

The continuous noise level can be measured effectively for simply a few minutes using a sound level meter. For further analyzing the sound, a sound level meter with octave band analysis is the preferred choice.

Octave bands help break down the noise into its separate frequencies, telling you precisely what frequency is producing the noise.

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Intermittent or Variable Noise

As opposed to continuous noise, noise is said to be variable or intermittent if it is a mixture of somewhat noisy and quiet periods.

Intermittent noise levels tend to increase and decrease rapidly; different operations or variable noise sources can cause the intermittent sound to change over time.

Examples include:

• a train passing by
• a washing machine on its ‘wash’ cycle
• factory equipment that functions in cycles
• aircraft flying over your house
• most manufacturing noises

Similar to continuous noise, intermittent noise is also measured using a sound level meter. However, for making an accurate calculation, you will also need to assess each occurrence’s duration and the period between each noisy and quiet cycle.

For more reliable estimation of intermittent noise level, it is suggested that you measure multiple cyclic occurrences and calculate an average.

If you use an integrating-averaging sound level meter, it will simply make the measurements for you.

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Impulsive or Impact Noise

Impulse or impact noise is defined as extremely short bursts of loud noise that last for no more than a second. This may seem to be a rather negligible period, but in a usually calm and peaceful environment, a single, extremely loud noise can also cause sufficient hearing damage.

These types of noise are most commonly linked to the demolition and construction industry. They can startle you due to their quick and unexpected nature.

Examples include:

• gunfire
• a balloon popping
• the noise created by punch presses
• explosions
• pile drivers

For measuring impulsive noise, a sound level meter, or a personal noise dosimeter that can measure Peak values is generally used. However, presently no mathematical description is available which clearly defines impulsive sounds’ calibration and rates their annoyance level.

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Low-frequency Noise

Low-frequency noises are a regular part of our routine soundscape, and we are exposed to them constantly. They include the faint background humming of a nearby power grid and a large diesel engine’s roar.

As is obvious from its nature, the low-frequency sound is the toughest type of noise to reduce, so it can easily travel and spread over long distances.

To effectively measure low-frequency noise, a sound level meter with third-octave band analysis should be used, so that the lowest of frequencies making up the noise can also be recorded.

To prevent the harmful health effects from noise pollution and continuous exposure, noise levels must be reduced to tolerable and acceptable levels.

The most effective noise reduction method is using engineering modifications to either modify the source of the noise or the environment in which the noise is causing problems, such as the workplace.

Keeping this in mind, we at soundear.com provide high-quality services to help companies monitor and control the level of hazardous noise. With 20 years of noise monitoring experience, we offer unique techniques to measure, control, and minimize noise to make your working environment more comfortable.

Soundear believes in creating awareness about the noise. For further assistance and facilitation, and to find out more about our services, products, and vision, visit the website here.