MK:440 Environmental Noise Microphone
Page 10 of 13
8
Maintenance & calibration
The system is designed to be durable and should not need routine maintenance other than
calibration. Under no circumstances should the preamp be removed from the enclosure and never
remove the microphone from the preamp.
It is recommended that the system is calibrated once a year to maintain the accuracy of the system,
it requires removal of the lid of the MK:440 and must be carried out by a competent person in a
suitable environment.
Remove the windshield and top preamp assembly by holding the windshield and black preamp and
unscrewing gently to avoid damaging the windshield. The will expose the microphone allowing an
acoustic calibrator to be placed over it.
A CR:514/CR:515 can be used to set an absolute reference point for the system. The calibrator emits
a 94dB tone, the current output then needs to be measured to determine the level being measured
by the device. Turning the screw on the blue resistor marked “CAL” will adjust the current output.
You will need to refer to your configuration to determine the correct current level for the calibrator
output (typically 94dB, see section 5 for an example on current levels).
If turning the “CAL” screw does not allow you to reach the required current level then it is likely that
there is a problem with the device and should contact your distributor.
8.1
Optional Accessories
The following accessories may be ordered separately from your distributor as required.
Windshield:
UA:440
Wall mounting Kit:
BP:440