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751 Hearing Conservation Program Management
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The Basics

Sound and Noise

Sound

Sound refers to any auditory sensation that is perceived by the ear. Sound is a series of small changes in air pressure that propagate as waves of positive pressure disturbances (compressions) and negative pressure disturbances (rarefactions), as shown image to the right.

Areas of compression, rarefaction and a sound wave.

Sound can travel through any elastic medium (e.g., air, water, wood, metal). It can be a single frequency or a combination of frequencies that form a pleasant or meaningful experience. Sounds can be intentional or unintentional, and they can range from speech and music to nature sounds and mechanical noises.

Noise

On the other hand, noise refers to any unwanted or unpleasant sound that interferes with the desired sound or interrupts the normal functioning of an activity.

Noise is usually characterized by its loudness, frequency, and duration and can cause stress, annoyance, and even health problems if it is present for extended periods of time.

The key difference between sound and noise is that sound is a general term that encompasses all audible sensations, whereas noise is an unwanted or unpleasant sound that disrupts a desired auditory experience.

Knowledge Check Choose the best answer for the question.

1-1. What is noise?