12
Operation
5. After inserting the microphone into the pistonphone, wait at least 1 minute.
Note
If calibration is performed immediately after inserting the micro-
phone, correct results can not be achieved due to the change in air
pressure. You must wait about 1 minute until the pressure inside
the microphone stabilizes. The exact amount of required time is
vary depending on the microphone. Refer to the documentation of
the microphone or the sound pressure measurement system (sound
level meter) for more information.
6. When the indication of the sound pressure measurement system (sound level meter)
has stabilized, read the indicated value.
7. Turn the power to the pistonphone on.
Wait until the indication of the sound pressure measurement system (sound level
meter) has stabilized. Then read the indicated value. Verify that the value is at
least 30 dB higher than the value obtained in step 6.
Important
If the difference in readings is less than 30 dB, correct
calibration will not be possible, due to the influence of
background noise.