HD2010UC/A
- 54 -
V4.1
A
COUSTIC CALIBRATION
In order to keep the acoustic sensitivity of the microphone-sound level meter chain steady
over time and in the different usage conditions, a reference sound source is used, which generates a
pure tone at a reference frequency with a given pressure level, stable over time. For this purpose
type 1 and type 2 (according to IEC 60942) acoustic calibrators compatible with UC52 microphone
capsule are used. For the HD2010UC/A sound level meter are available Class 1 HD2020 and Class
2 HD2022 calibrators.
The control that the reference sound level provided by the acoustic calibrator is correctly
measured by the sound level meter (it is normally acceptable that the difference between the sound
level measured by the sound level meter and the nominal level of the calibrator be lower than
0.5dB) has to be carried out before and after a series of measurements, to ensure that measured val-
ues are correct. When the difference between the calibrator sound level measured by the sound level
meter and the nominal value is higher than 0,5dB , a new acoustic calibration has to be carried out.
Warning: to prevent damaging the sound level meter, it is important, during the calibration
procedure, to follow carefully the on-screen instructions and the indications provided by this
manual
.
Operating Procedure
Switch on the sound level meter, if necessary, press STOP to finish the measurement on
progress, and perform the following procedure. The program will automatically control that the
warm-up time, indicated by a flashing W, is over.
1.
Press PROG and, with the help of the DOWN arrow, select "Acoustic calibration". Press
SELECT to start calibration.
2003/01/01 10 00 00
:
:
Batt 95% Mem 92.5%
:
:
ACOUSTIC CALIBRATION
Last:2003/01/01 10.00
Calibr.level 94.0dB
Leq dBC
Insert and turn on
the calibrator.
95.3
SELECT PROGRAM
Electric Calibration
Acoustic Calibration
Frequency Response
...
NEXT
EXIT
2.
The first screen shows the date of the last calibration (Date:…) and, in the line below, the
calibrator sound level to be used in the calibration in progress (this value can be modified,
before starting the calibration program, by selecting “Calibration Level” from the MENU:
see page.44). Gently insert the microphone in the calibrator hole and switch it on.
3.
Select the sound level indicated on the sound level meter display (94dB is the reference
value), then press NEXT to continue.
4.
Now, the instrument measures the sound level applied and waits for it to become steady: the
measured level will be displayed. The indication "Waiting for level stabilization…" will be
viewed.
When the sound level has stabilized, the measured value is compared to the reference one
and if the difference is acceptable, it is logged. In this case, the message
“Turn off the
Calibrator”
will appear. Press NEXT to continue.