Leq Metering
Introduction
Leq encompasses a set of sound level meter specifications, which are described in detail in the BS EN 61672-1 European Standard.
FLUX:: Analyzer implements the following Leq measurements: time-weighted sound level, time-average sound level and sound exposure level.
Frequency weighting is employed for all measurements, A being the standard and default, although other weightings can be specified if necessary.
The Leq module always measures the audio routed through the Mic channel.
Time-weighted sound level
LA is the root-mean-square sound level obtained after exponential time weighting.
Exponential averaging has the effect of progressively ‘forgetting’ past sample values.
The norm specifies two time-weighting constants:
- Fast : 125ms
- Slow: 1s
The corresponding letter symbol is LAF for an A-frequency weighted and F time-weighted sound level, for example.
Time-average sound level
Time-average sound level is basically an RMS meter with frequency-weighting applied.
Sound exposure level
This measures the sound exposure equivalent to a ‘dose’ received for a second.
It is useful for determining the amount of sound pressure to which listeners have been exposed for a certain duration.
This value naturally increases with time. For a constant source level, this value increases in a logarithmic fashion.
Mic. channel Leq setup
Mic. channel Leq setup
Zero ref.
Adjusts the reference point. See RMS for more information.
Weighting
Frequency weighting employed. Can be switched between ANSI standard (A, B, C, D) and none. The default is A.
Time-weighted F
Indicates the time-constant for the Fast time-weighted sound level.
Time-weighted S
Indicates the time-constant for the Slow time-weighted sound level.
Average integration
Sets the integration time for the time-average sound level, between 1s and 14400s (4 hours). Default is 10s.
Main display
Switches the main measurement display from time-average sound level (the default) to sound exposure level.
SPL
SPL reference
This is the reference level of the calibrator’s output, indicated on the device itself or in the corresponding datasheet. A typical value is -94dB.
SPL trim
This is the offset applied to RMS dB values in order to obtain dB SPL readings. It is determined automatically by the calibration procedure.
Calibrate
Press this button after having insert the microphone into the calibrator socket and activated it in order to determine the SPL trim value.
Color
The following settings control the visual aspect of the Leq display.
Font back
Common font background color.
Main level font color. ### Level
Time-weighted F
Fast time-weighted level font color.
Time-weighted S
Slow time-weighted level font color.
Name
Name font color
Unit
Unit display font color.
Freq. weighting
Frequency weighting type display font color.
Font blur
Toggles font blurring on (default) and off.