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D00073611 Siemens SD 270 Service Manual
Pressing the ‘MASK’ key will enable narrow-band noise calibration in
the
opposite
ear to the one selected. Change the calibration level by
using the ‘MASK’ control. Left and Right earphones should both be
calibrated. The ‘SIGNAL’ control continues to adjust the calibration of
the tone in the selected earphone.
Pressing the ‘SPEECH’ key will enable calibration for speech and also
for the speech-weighted noise in the
opposite
ear to that selected.
For speech calibration apply a 1kHz sine wave signal of 1Vpk to
the LINE-IN socket on the back of the unit (refer to Section 2.7 of
this manual) and adjust the ‘Hz </>’ keys until 0dB is indicated on
the LEVEL dB bar graph (the top two LED elements should be
extinguished). Now adjust the calibration output level by using the
‘SIGNAL’ control to read the correct level on a sound level meter.
This should be done for both Left and Right earphones
.
For calibration of speech-weighted noise in the
opposite
ear to
the one selected change the calibration level by using the ‘MASK’
control. This should be done for both Left and Right earphones.
Note that the ‘SIGNAL’ control will continue to adjust the speech
calibration
Pressing the ‘BONE’ key will enable calibration of the bone vibrator.
Change the calibration level by using the ‘SIGNAL’ control. There are
10 different frequencies to calibrate (250 to 8k).
Pressing the ‘MASK’ key while in ‘BONE’ mode will enable calibration
of narrow-band noise in the masking insert (if supplied). Change the
calibration level by using the ‘MASK’ control. Note that the ‘SIGNAL’
control will adjust the calibration of the tone in the bone vibrator.
To store the calibrations and leave calibration mode, press the
‘STORE’ key once. This will display the calibration date. If this date is
incorrect use Softkeys 3 and 4 to select the required date field (day,
year, month) and use Softkeys 1 and 2 to change the date as
required. Press the ‘STORE’ key to confirm and exit calibration mode.
3
Secondary Headphone
If a secondary type of earphone has been enabled for use with the
audiometer (e.g. the E-5A insert earphone) this may be selected from the