Sound In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by ...

level Level or levels may refer to: Engineering *Level (instrument), a device used to measure true horizontal or relative heights *Spirit level, an instrument designed to indicate whether a surface is horizontal or vertical * Canal pound or level * Re ...

refers to various logarithmic measurements of audible vibrations and may refer to: *

Sound exposure level Sound exposure is the integral, over time, of squared sound pressure. The SI unit of sound exposure is the pascal squared second (Pa2·s). Mathematical definition Sound exposure, denoted ''E'', is defined by :E = \int_^ p(t)^2\, \mathrmt, where *t ...

, measure of the sound exposure of a sound relative to a reference value *

Sound power level Sound power or acoustic power is the rate at which sound energy is emitted, reflected, transmitted or received, per unit time. It is defined as "through a surface, the product of the sound pressure, and the component of the particle velocity, at ...

, measure of the rate at which sound energy is emitted, reflected, transmitted or received, per unit time *

Sound pressure level Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophon ...

, measure of the effective pressure of a sound relative to a reference value *

Sound intensity level Sound intensity, also known as acoustic intensity, is defined as the power carried by sound waves per unit area in a direction perpendicular to that area. The SI unit of intensity, which includes sound intensity, is the watt per square meter (W/m2 ...

, measure of the intensity of a sound relative to a reference value *

Sound velocity level Particle velocity is the velocity of a particle (real or imagined) in a medium as it transmits a wave. The SI unit of particle velocity is the metre per second (m/s). In many cases this is a longitudinal wave of pressure as with sound, but it can ...

, measure of the effective particle velocity of a sound relative to a reference value

See also