Fig 8. Acoustic calibration of microphone
Fig 9 Calibration setup
First row: Acoustic Calibration. You can use acoustic calibrator to calibrate the sensitiv-
ity of the instrument.
Second row: Calibration Setup. You can set the SPL of the acoustic calibrator or the
sensitivity of the microphone.
Third row: Calibration History of the instrument.
“Lp= dB 94”: The number “94” is the SPL of the calibrator, i.e. the SPL for the instrument
to be calibrated. The data after “Lp=” is the SPL which is measured by the instrument
during the calibration. “Lx= dB -30.0”: The number “-30.0” is the sensitivity level of
microphone. The data after “Lx=” is the newly calibrated sensitivity level of the micro-
phone. Range: 25-120 dBA the lower measurement range with the Lx above.
Move the cursor to the second row on the calibration submenu, press key and
enter calibration setup interface. The following message appears:
“Serial:”: Serial number of the microphone set by the producer. It cannot be modified.
“MIC.Sen.”: Sensitivity level of the microphone. You can adjust the sensitivity level of the
microphone by pressing or key.
“Cali.SPL”: Sound pressure level of the calibrator. If your calibration SPL is not 94.0 dB,
press or key to make it reach the output SPL of the calibrator. Press key
after the adjustment, the instrument will save the operation and display “OK” on the
lower right corner of the screen.
When sound level calibrator is installed on the microphone, turn on the power supply.
Press key to initiate the calibration process. A digit is displaying on the lower right
corner of the screen, which change to 9 from 0 and then pauses, press key and the
new microphone sensitivity level is saved.
Move the cursor on the first row and press key, then you enter the calibration
interface. The display shown as follows:
5.1 Acoustic calibration
5.2 Calibration setup (Use ST-120 Calibrator)
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