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If a calibration of the speech channel is not required:
The output of the external amplifier should be set in order to
achieve the level specified above at 1000Hz (i.e. 72dBSPL) as
measured by the SLM with the audiometer set to 0dB compen-
sation. The amplifier’s level control should
not then be changed.
When 1kHz, Left channel has been calibrated:
At every other frequency the adjustment should then be made
as follows to give the above values as measured by the SLM.
• Change frequency using the <- Hz -> keys and then adjust the
calibration level for the new frequency using the SIGNAL control
to reach the correct level as measured by the SLM.
• Repeat the above until all frequencies have been calibrated for
the Left channel.
• To calibrate the Right channel (if required) press the RIGHT key
(do not change the amplifier’s volume control).
• Adjust the calibration for all of the right channel frequencies
(including 1000Hz) by using the <- Hz -> keys and the SIGNAL
control as described above.
• To store the levels and leave Free-field calibration mode, press
the STORE key.
• If required, all calibration levels can be set to a default of zero
by pressing Softkey 1 (‘Zero all’) while in free-field calibration
mode.
It is possible that, because of the characteristics of the listening
room or test set-up, the calibration levels above cannot be achieved
because the limit of adjustment is reached for one or more frequen-
cies. Re-arrangement of the listening room may improve the situati-
on, but if not, the following is a possible solution: