|Sound pressure||p, SPL|
|Particle velocity||v, SVL|
|Sound intensity||I, SIL|
|Sound power||P, SWL, LWA|
|Sound energy density||w|
|Sound exposure||E, SEL|
|Speed of sound||c|
Sound exposure, denoted E, is defined by
- the exposure is being calculated for the time interval between times t0 and t1;
- p(t) is the sound pressure at time t, usually A-weighted for sound in air.
Sound exposure level
Sound exposure level (SEL) or acoustic exposure level is a logarithmic measure of the sound exposure of a sound relative to a reference value.
Sound exposure level, denoted LE and measured in dB, is defined by
- E is the sound exposure;
- E0 is the reference sound exposure;
- 1 Np = 1 is the neper;
- 1 B = 1/ ln 10 is the bel;
- 1 dB = 1/ ln 10 is the decibel.
The commonly used reference sound exposure in air is
The proper notations for sound exposure level using this reference are LW/(400 μPa2⋅s) or LW (re 400 μPa2⋅s), but the notations dB SEL, dB(SEL), dBSEL, or dBSEL are very common, even if they are not accepted by the SI.
- "Letter symbols to be used in electrical technology – Part 3: Logarithmic and related quantities, and their units", IEC 60027-3 Ed. 3.0, International Electrotechnical Commission, 19 July 2002.
- Ross Roeser, Michael Valente, Audiology: Diagnosis (Thieme 2007), p. 240.
- Thompson, A. and Taylor, B. N. sec 8.7, "Logarithmic quantities and units: level, neper, bel", Guide for the Use of the International System of Units (SI) 2008 Edition, NIST Special Publication 811, 2nd printing (November 2008), SP811 PDF