Terminology

Absorption (sound)

The process of sound energy dissipating as it is converted into thermal energy.

Absorption coefficient

A unit of measurement indicating how much of the sound is absorbed in the actual material.

Ambient Noise

The background noise in a room or area, being a combination of many sources of sound within the area.

Amplitude

The amplitude is the measure of the amount of energy in the sound wave, measured from the fixed point of the wave to the crest (positive amplitude) or to the trough (negative amplitude).

Decibel

A decibel (dB) is a unit of measurement of the loudness or strength of a sound.

Frequency

Frequency of sound means the number of vibrations or cycles per second a sound wave generates.

Impact Insulation Class (IIC)

The insulating properties of the floor-ceiling assembly with respect to sounds such as footsteps.

Loudness

The intensity of a sound as perceived by an individual.

Mass

The thickness of an object, specifically a wall, ceiling or floor partition, that acts as a barrier to sound.

Mechanical decoupling

The physical disconnection between two sides of a partition used to decrease vibrations and increasing sound deadening.

Noise Reduction Coefficient (NRC)

A measure of the sound absorption qualities of a material. It is calculated by averaging the material's sound absorption coefficients at frequencies of 250, 500, 1000, and 2000 Hz.

Reverberation

The echoing of a sound caused by reflection of sound waves from surfaces in the room.

Sabin

A unit of acoustic absorption equivalent to the sound absorption of one square foot of a surface that completely absorbs sound, such as as open window.

Sound

Sound is the vibration of the individual molecules of any substance, transmitted through solid, liquid or gas.

Soundproofing, Sound Deadening, Sound Damping

Using materials or building processes to lower or eliminate the noise level within a given area.

Sound Transmission Class (STC)

The rating of airborne sound transmission that describes the degree of sound isolation provided by a home construction and materials.

Wavelength

The wavelength is the horizontal distance between two identical and successive points of a sound wave.