Larson Davis System 824, Technical Reference Manual

Page: 324 / 673

9-12 824 Reference Manual 9/29/09
After reaching equilibrium with the ambient environment
and switching the power on, the elapsed time until the meter
may be used to measure the sound level is as follows:
• < 10 seconds using a prepolarized (electret) microphone
• < 1 minute using a traditional condenser microphone
requiring a polarization voltage.
When performing an integrating measurement, the data is
available during and immediately following the
measurement time interval.
Averaging Time
The averaging time is determined by how long the
measurement is allowed to run, as indicated by the digital
display in the lower left of the screen. For low level
measurements where the measured level may be affected by
the system noise floor, it is recommended that an averaging
time of at least 30 seconds be used. For timed
measurements, the value of the averaging time can be preset
and the instrument configured to stop automatically after
that time as described in the section ”Measuring for a Preset
Integration Time” on page 9-16.