Free-field correction

For most accurate calibration of the microphone sensitivity, the following free-field correction should be used when calibrating with the NTi Audio class 1 sound calibrator,

• M2211, M2215, M2230 and M2340: –0.10 dB

and the following correction with the NTi Audio class 1 sound calibrator with 1/4" adapter ADP 1/4-P:

• M4260: +0.10 dB

• M4261: +0.20 dB

All NTi Audio measurement microphones are free-field equalized measurement microphones. The irritation of the free-field level due to the presence of the microphone body in the sound field is already compensated for in the microphone. The calibrator measures in the pressure field. Therefore, the level at the microphone diaphragm differs by –0.08 dB for 1/2" measurement microphones at the reference ambient conditions.

• M2340, M2230 with 50 mm windscreen
  The correction value is +0.12 dB; thus a calibration level of 114.00 dB must be set on the XL3
  (i.e. 114.00 – 0.08 + 0.12 = 114.00).

• M2340, M2230 with 90 mm windscreen
  The correction value is +0.19 dB; thus a calibration level of 114.11 dB has to be set at the XL3
  (i.e. 114.00 – 0.08 + 0.19 = 114.11).

• M2340, M2230 with WP30 windscreen 90 mm
  The correction value is +0.19 dB and thus a calibration level of 114.11 dB has to be set on the XL3
  (i.e. 114.00 – 0.08 + 0.19 = 114.11).

Configuration:

• XL3 + M2340 measurement microphone

• NTi Audio class-1 sound calibrator with 114.00 dB

Setting for customer calibration

• The level for user calibration must be set to 113.90 dB (= 114.00 – 0.10) at .

• Plug the calibrator onto the microphone and turn it on

• Select Start and press the key.