Noise

Professional Definition

Any undesirable, unpleasant, annoying, disruptive, or harmful sounds affecting a person.

From a physics perspective, noise is often an aperiodic (non-periodic) vibration with a complex spectral structure. However, a key element of the definition is the subjective factor – intent and perception. A sound with the same sound pressure level (SPL) can be regarded as a useful signal (e.g., music at a concert) or as noise (the same music heard through the wall in the bedroom).

Acoustics in Simple Words

Imagine a beautiful garden. A rose is a noble flower, right? But if that same rose grows in the middle of a cornfield, the farmer will call it a weed. Noise is just such an acoustic weed. It is any sound that is in the wrong place and time, disturbing us while we work or rest. Even the most beautiful symphony of Beethoven becomes noise when you are trying to concentrate on a challenging math problem.

Summary

Noise is a relative concept, depending on the context and the listener's disposition, although its harmfulness (e.g., hearing damage) is objectively measurable. In acoustic engineering, we strive to minimize these unwanted energies to protect people's health and comfort.