Norsonic nor1217, Инструкция по эксплуатации

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4 Chapter 3
Microphone calibration
Microphone calibration
The Nor1217 can be calibrated with a sound calibra-
tor for ½” microphones without the need for special
couplers. We recommend using Nor1251 (1000 Hz) or
Nor1253 (250 Hz).
Unscrew the upper part of the microphone to gain
access to the microphone cartridge. Mount the cali-
brator slowly and carefully while turning the calibrator
and switch it on. See figure.
If the calibrator frequency is 250 Hz, adjust the
reading to be the level stated for the calibrator, e.g.
124,0 dB for Nor1253 with 124 dB specified level.
If the calibrator frequency is 1000 Hz, adjust the
reading to be 0,1 dB below the stated calibrator level,
e.g. 113,9 dB for Nor1251 calibrator with a stated level
of 114 dB.
This is only valid if the frequency response correc-
tion is turned off. For the Nor140 the frequency cor-
rection is turned off, when entering into the calibration
menu. Perform calibration and calibrate the micro-
phone as a normal free field microphone. I.E. -0.1 dB
if using a 1000 Hz calibrator. When leaving the cali-
bration menu, you will observe that the level measured
with the calibrator on, is different from what obtained
in the calibration mode. This is correct, and is due to
the frequency correction added. If horizontal position
is selected, the signal will be about 0.1 dB higher than
the calibrated signal, in vertical position the signal will
be 0.3 dB lower than the calibrated level. This does
not apply if you calibrate with a 250 Hz calibrator since
there is no correction added at this frequency.