BRUEL & KJAER 2221 - Leq and SEL Measurements; Max Hold Fast;Slow Measurements

For measurements in a diffuse field, the Random Incidence Adaptor DZ 9566 should be
mounted on the microphone, and the meter may be oriented in any direction in the diffuse
field. A diffuse field can generally be assumed for indoor measurements or in reverbera-
tion rooms.
3.5.3. Leq and SEL Measurements
1. Carry out the calibration check before commencing with a measurement:
2. Set the controls on the Sound Level Meter as follows:
FUNCTION: Leq or SEL
Leq RANGE: in order to include the expected value
MODE:
"Run"
POWER:
"On"
3. To begin measurement, press RESET.
The Leq or SEL value measured can be read directly from the display which is updated
twice per second while the measurement is running. Alternatively the measurement can
be interrupted by setting the MODE switch to "Pause". The "A" displayed indicates that
A-weighting is applied.
If an input overload occurs, the sign "•" appears (held continuously) and the reading may
be incorrect. Switch Leq RANGE to a higher range. If the input signal is underrange the
sign "'f'" appears. If it is displayed too often, switch Leq RANGE to a lower position.
Switching between measuring ranges automatically resets the instrument.
The Leq measurement duration for periods shorter than 2,77 hours can be obtained by
substracting the measured Leq from the SEL value and using the conversion table at the
back of the instrument. SEL is obtained by setting FUNCTION to "SEL". See Fig.3.7.
The Leq value displayed for measurements over a period of more than 2,77 hours will be
incorrect and a "*" will appear on the display. However, knowing the measurement
duration, the correct Leq value can be obtained from the SEL indication using the
conversion table at the back of the instrument.
The measurement period for an SEL measurement is only limited by the battery life.
Note: It is possible to switch between "Leq" and "SEL" during a measurement without
loosing the results. When measuring low levels it is recommended to set the MODE switch
to "Pause" before switching between "Leq" and "SEL", as the clicking noise from the
switch may introduce an error. This is irrelevant when measuring higher levels.
3.5.4. Max Hold "Fast" or "Slow" Measurements
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1. Carry out the calibration check before commencing with a measurement.
2. Set the controls on the Sound Level Meter as follows:
FUNCTION: Max Hold "Fast" or "Slow"
Leq RANGE:
MODE:
POWER:
to include the expected value
"Run"
"On"