User:Moonexma/sandbox

Sound Fields
As sound is emitted from a source it propagates through different sound fields. Each has its own unique properties, the most common being; near field. far field, free field, and reverberant field.

Understanding the sound levels of each field is an important of modeling how sound from a source behaves.

Near Field
"The near field region is probably the most difficult to predict as this describes the region where noise propagation is not well developed and construction techniques and equipment installation details that are generally unknown affect the amount of noise around the equipment or structure. "

Far Field
"The far field starts where the sound field becomes more stable and propagation is fairly uniform. This location is frequency (wavelength) dependent and is usually two to four major source dimensions (width and height as you look at the source) away from the noise source. "

Free Field
"The free field describes where sound freely propagates and spreads uniformly. The sound level decreases approximately six decibels for every doubling of distance. As you get farther away from the source the decay rate starts to flatten out once the sound from the source approaches the ambient or background sound level as illustrated in the right section of the figure."

Reverberant Field
"The reverberant field occurs where freely propagating sound waves are reflected back from a wall, a ceiling, or other surfaces again causing variation in sound levels as illustrated. "