SM010-3 Siemens SD 270 Operating & Service Manual Page 57
Note also that the option to output free-field equivalent levels in speech
mode is only available for the DD45 & TDH-39 earphones.
To set an alternative secondary earphone type:
Enter calibration mode using the password as described in
Appendix 5 Section 1
Press the TALKBACK key to cycle around the selection of primary
earphone, secondary earphone and the main calibration display
With “Secondary phones” displayed use the Hz > key to cycle
through the available options (none,DD45,THD39,TDH49,E-5A)
until the required earphone type is displayed
Press the OPTIONS key to save the selection
If the secondary earphone is set to None (or the same as the primary
earphone) then only the primary earphone will be enabled and the option
for the operator to select a secondary earphone will be disabled.
Before calibrating the secondary headphone ensure the correct earphone
type is displayed at the right of the lower line. If necessary use the
PHONES key to switch between the primary and secondary earphone
types and then calibrate as described in Appendix 5 Section 2. To retain
existing calibration values for other transducers do
not
use the ‘+20dB’
key to set all calibration levels to zero.
Unless all other transducers are being calibrated at the same time it is
recommended that the calibration date is not changed but left as the date
of the original calibration. This will keep the calibration of the alternative
secondary headphone in step with the remainder of the transducers.
On completion, the calibration process should be verified. The table in
Appendix 5 Section 4 may be used for this purpose, and if necessary the
entire calibration process should be repeated.