5.2 Use ST-120 to calibrate
At the first time of sound calibration, set the "calibrator’s sound pressure level" accord-
ing to the certificate of inspection of the corresponding sound level calibrator. General-
ly, the sound level calibrator’s sound pressure level is 94.0dB. If the sound pressure
level is not 94.0dB, set it according to the actually inspected result.
Take 94.2dB for example, press key, and press or key to move the cursor to
"Calibrator", and then adjust the value to 94.2 by or key. At last, press to
save the Calibrator SPL.
Every time the user presses or key, the value increases or decreases by 0.1dB.
When the user presses and holds or key, the value increase or decreases by 1dB.
The adjustment continues till the key is released. The above steps can be performed
only when the displayed sound pressure level differs from the used sound pressure
level.
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In the current mode, the cursor can only be moved on "dBA" at the right side of "Current
SPL" and "Calib.". If the user wants to modify the parameters, they should press Key,
shown below:
The status changing from "Ready" to "Modify" allows the user to modify "Free field",
"Calibrator SPL", and "New Sensiti." by pressing or key. When key is pressed,
the modified content will be saved.
When the new sensitivity level that is calibrated differs from the last one by more than
4dB, then the new sensitivity level can’t be saved. And the instrument should be
recalibrated according to the prompt, if the microphone is verified with no problem
(such as change the microphone), the user can set the new sensitivity level manually
and calibrate it again.
