13 Direction for use and maintenance of the sound
level meter
13.1Use warnings
The sound level meter is a measuring instrument using the latest technologies. To maintain accuracy and required reliability, avoid any
chock of the housing and the microphone and keep them away from humidity and corrosive steams.
13.2Direction for use
For each application, you should check measurement technique and conditions in order to get valid and coherent results. The way of
using the instrument has at least as much importance on result than device quality. You have to take into account at least the following
parameters:
•
The sound level meter is designed for a free-field acoustic measurement
•
The instrument is held with reached out arm for short-time measurement or positioned on a tripod for
long-time measurement.
•
The axis of the instrument must face sound source, do not interfere with your own body or with any
close material item (furniture, machines, low wall, trees, etc...).
•
Protect the instrument from bad weather, and use as much as possible the windscreen. It protects the
microphone and minimizes the disruptive effects linked to air currents during measurement.
•
Calibrate the instrument regularly with a suitable calibrator CAL300 (class 1) or CAL200 (class 2) type.
13.3Calibration
A calibration must be performed regularly with a suitable calibrator.
➢
Insert the adapter ring according to the diameter of the microphone sound level meter.
➢
Place the calibrator on the microphone, until the microphone reaches the end of the ring. Do this move
slowly and smoothly so as not to damage the microphone.
➢
Put vertically the sound level meter and the calibrator.
➢
Turn on the calibrator.
➢
Wait for a moment a correct level of acoustic pressure of the calibrator: for example 94.0 dB .
➢
You can begin the procedure of calibration of the instrument as explained below.
Reminder: free-field coefficient
An acoustic reference source, a calibrator or a pistonphone supplies a level of acoustic pressure. During a free-
field measurement, phenomenons of diffraction caused by the microphone and the housing come to affect the measurement. This
perturbation est minimized if the microphone is far from the housing.
For this sound level meter, the induced free-field perturbation is very low, and it is not necessary to introduce a free-field correction.
Operating mode
➢
From starting screen, select
Cal.
with arrows keys then
press
OK
.
Direction for use and maintenance of the sound level meter
52
Ref : dB
C.Cl dB
LCF dB
Corr. dB
CALIBRATION
94.0
0.0
---;-
0.5
05/10/2011
