Acoustic Glossary


 

Sound Energy Terms, Definitions, Units, Measurements ...


Sound Energy is the energy present in a sound field, the SI unit is the joule (J).

Sound Energy is related to the sound pressure, particle velocity and the density of the media.

Sound Energy also known as acoustic energy, causes mechanical vibration in any medium through which a sound wave passes, including air and the human eardrum.

Sound produces a relatively low level of energy when compared to other forms of energy


Sound Energy Level is the logarithmic ratio of the sound energy to the reference sound energy.

Sound Energy Level Lw = 10 lg (w/wo) dB, where w is the sound energy and wo is the reference sound energy level of 10-12 joule ≡ 0 dB

  3 dB is a factor of 2, twice or half the energy.
10 dB is a factor of 10 increase or decrease in the sound energy.
20 dB is a factor of 100
40 dB is a factor of 10000 etc.,

See also our sound level calculations article

Related Terms - listed alphabetically

Reference Sound Energy (Wo) = 10-12 Joule ≡ 0 dB

Reference Sound Energy Density (wo) = 1 pJ/m3 = 10-12 J/m3 ≡ 0 dB

Sound Energy Density (w) is the time-averaged sound energy per unit volume, the SI unit is the joule per cubic metre (J/m3).

Sound Energy Density Definition IEC 801-21-41, sum of the instantaneous potential and kinetic energy densities and is also known as the total energy density

 

Instantaneous Kinetic Sound Energy Density Definition IEC 801-21-40, half the product of the density of the medium and the square of the velocity of a particle in the said medium.

 

Instantaneous Potential Sound Energy Density Definition IEC 801-21-39, half the quotient of the square of the instantaneous sound pressure by the modulus of elasticity of the medium.


Sound Energy Density Level is the logarithmic ratio of the sound energy density to the reference sound energy density

Sound Energy Density Level (LE) = 10 lg (E/Eo) dB
where E is the sound energy density and Eo is the reference sound energy density level = 10-12 J/m3 ≡ 0 dB

20 dB is a factor of 100
40 dB is a factor of 10000 etc.,


Sound Energy Flux is the average sound energy flowing through a specified area

Sound Energy Flux (q), the SI units are W/m2 = J s/m2

Sound Energy Flux Definition IEC 801-21-37, time average product of the in-phase components of the instantaneous sound pressure and the volume velocity through the surface element considered, and is also known as the sound power through a surface element


Sound Energy Flux Density Definition IEC 801-21-38, sound energy flux in a specified direction and sense through an area perpendicular to that direction, divided by the area, and is also known as sound intensity and sound power density

Sound Energy Flux Density units are watts per square metre.


Sound Energy Flux Density Level Definition IEC 801-22-06, logarithm of the ratio of a given intensity of sound in a stated direction to the reference sound intensity. Such intensity level in decibels is ten times the logarithm to the base ten of the ratio, and is also known as the sound intensity level.

Note : unless otherwise specified, the reference sound intensity is 1 pW/m2
See also the IEC Definition of Level

See also • noise dosesound exposure
Related terms • Leqsound intensitysound powersound pressure
 
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