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• Set all of the frequencies for which calibration can be achieved.
• For frequencies where this is not possible, adjust each to be a
multiple of 5dBs from the required level.
• Produce a correction table for each frequency for which calibra
tion could not be achieved to be applied to the output level of the
audiometer while conducting a test to relate the instrument dis
play to actual output level from the speakers.
5.2. Calibrating the Competing Noise Channel
This part of the calibration procedure may be omitted if Free-field
speech calibration is not required.
• Enter the Free-field calibration mode as described in A2 5.1.
• Press the SPEECH key and the display will change to indicate the
option to adjust the competing noise calibration level – the
legend “Sp Mask” is used to indicate this.
• Without changing the setting on the external amplifier use the
SIGNAL control to adjust the level of the competing noise to
90dBSPL as measured by the SLM using dBA settings.
• Calibrate each channel, pressing the RIGHT and LEFT keys to
switch between channels.
• If necessary it is possible to switch between speech (competing
noise) and warble calibration modes by pressing SPEECH and
WARBLE respectively.
• To store the levels and leave Free-field calibration mode, press
the STORE key.