A Glossary of noise measurement terminology

Below is a glossary of noise measurement terminology. If you have any questions about what any of these terms mean or if you need any help with understanding noise measurement terms, please get in touch and we will be pleased to help.

1:3 Octave Band Filters Single 1:1 Octave bands divided into three parts.
1:1 Octave Band Filters A division of the frequency range into bands, the upper frequency limit of each band being twice the lower frequency limit.
A Weighting A standard weighting of the audible frequencies designed to reflect the response of the human ear to noise.
Acoustic Calibrator An instrument that provides a reference noise source that is used to calibrate and check the performance of a Sound Level Meter.
Broadband Noise Measurements using parameters which include all the audible noise, such as dB(A) and dB(C)
C Weighting A standard weighting of the audible frequencies used for the measurement of Peak Sound Pressure level.
CE Marking A label used to show that the Sound Level Meter conforms to the specification of a European Directive
Data Logging Measurements can be stored in the Sound Level Meter for download to a PC
dB(A) Decibels A weighted
dB(C) Decibels C Weighted
dB(Z) Decibels Z weighted
Decibel (dB) The units of sound level and noise exposure measurement
DIN 45641 German Standard which defines the additional measurements LAFTeq & LIeqT
% Dose The noise exposure expressed as a percentage (%) of a fixed level for 8 hours
Exposure Noise Exposure in Pa2h (Pascal Squared Hours)
Fast Time Weighting A standard time weighting applied by the Sound Level Meter
IEC 60804:1984 The International Standard for Integrating & Integrating-Averaging Sound Level Meters
IEC 61672:2002 The International standard for Sound Level Meter and Integrating Averaging Sound Level Meters has superseded both IEC 60651 and IEC 60804
IEC 60651:1979 The International Standard for Sound Level Meters
IEC 61260:1995 The International Standard for 1:1 Octave & 1:3 Octave Band Filters
Impulse Time Weighting A standard time weighting applied by the Sound Level Meter
Integrating Averaging Sound Level Meter A Sound Level Meter which accumulates the total sound energy over a measurement period and calculates an average
LA10 The noise level exceeded for 10% of the measurement period with 'A' frequency weighting calculated by statistical analysis
LA90 The noise level exceeded for 90% of the measurement period with 'A' frequency weighting calculated by statistical analysis
LAE Sound Exposure Level (SEL) with 'A' frequency weighting
LAeq,t Equivalent continuous sound pressure level. A measure of the average sound pressure level during a period of time, t, in dB with 'A' weighting.
LAF Sound level with 'A' Frequency weighting and Fast Time weighting
LAFmax The maximum Sound level with 'A' Frequency weighting and Fast Time weighting
LAFTeq Takt maximal sound level as defined by DIN 45641
LAI Sound level with 'A' Frequency weighting and Impulse Time weighting
LAImax The maximum Sound level with 'A' Frequency weighting and Impulse Time weighting
LAS Sound level with 'A' Frequency weighting and Slow Time weighting
LASmax The maximum Sound level with 'A' Frequency weighting and Slow Time weighting
LCE Sound Exposure Level (SEL) with 'C' frequency weighting
Lceq,t Equivalent continuous sound pressure level. A measure of the average sound pressure level during a period of time, t, in dB with 'C' weighting.
LCF Sound level with 'C' Frequency weighting and Fast Time weighting
LCFmax The maximum Sound level with 'C' Frequency weighting and Fast Time weighting
LCI Sound level with 'C' Frequency weighting and Impulse Time weighting
LCImax The maximum Sound level with 'C' Frequency weighting and Impulse Time weighting
LCpeak Peak Sound pressure level with 'C' frequency weighting
LCS Sound level with 'C' Frequency weighting and Slow Time weighting
LCSmax The maximum Sound level with 'C' Frequency weighting and Slow Time weighting
LEP,d Daily personal noise exposure
Leq Equivalent continuous sound pressure level. A measure of the average sound pressure level during a period of time, t, in dB
LIeqT Impulse weighted Leq,t as defined by DIN 45641
Ln Statistical analysis of noise levels. The n denotes the percentage exceedence.
LZE Sound Exposure Level (SEL) with 'Z' frequency weighting
LZeq,t Equivalent continuous sound pressure level. A measure of the average sound pressure level during a period of time, t, in dB with 'Z' weighting.
LZF Sound level with 'Z' Frequency weighting and Fast Time weighting
LZFmax The maximum Sound level with 'Z' Frequency weighting and Fast Time weighting
LZI Sound level with 'Z' Frequency weighting and Impulse Time weighting
LZImax The maximum Sound level with 'Z' Frequency weighting and Impulse Time weighting
LZS Sound level with 'Z' Frequency weighting and Slow Time weighting
LZSmax The maximum Sound level with 'Z' Frequency weighting and Slow Time weighting
Overload The input to the Sound Level Meter is too high for the current measurement range. Change the range
Peak The maximum value reached by the sound pressure at any instant during a measurement period (in dB usually with C frequency weighting)
SEL Sound Exposure Level, displayed as LAE, LCE or LZE
Slow Time Weighting A standard time weighting applied by the Sound Level Meter
Sound Level Sound Pressure Level with a Frequency weighting, such as dB(A)
Sound Level Meter An instrument for measuring various noise parameters
SPL Sound Pressure Level, the basic measure of noise level, expressed in decibels
Statistical Analysis A calculation performed by a Sound Level Meter on the noise levels measured during the measurement period to describe the statistical spread of the noise.
Type 2 General Field Grade for Sound Level Meter
Type 1 Laboratory & Field Grade for Sound Level Meters
Under Range The input to the Sound Level Meter is too low for the current measurement range. Change the range
Z Weighting Z weighting is a flat frequency response between 10Hz and 20kHz ±1.5dB excluding microphone response.
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