Page 26
D00073611 Siemens SD 270 Service Manual
Appendix 1 - Speech Audiometry
The Siemens SD 270 audiometer may be used in the following speech
modes of operation. However users should be aware that there is a
growing body of professional opinion that Live Voice speech audiometry is
generally not recommended. For recorded speech audiometry, only
material with a stated relationship with the calibration signal should be
used. Softkey 1 switches between MIC1 (live) or LINE (recorded) inputs.
Headphone and Free Field Testing
Note that the line outputs from the instrument (used for free-field testing)
are only active when FREEFIELD is selected.
If headphone testing is being performed, it is recommended that any
attached amplifier should be switched off
If Free Field testing is being performed, this option must always be
selected on the audiometer; this disconnects headphones, bone
vibrator and masking insert outputs, and ensures that the correct
calibrated output levels are achieved
Free-field equivalent output is available from the headphones in
Speech mode (see Section 3.6 of this operating manual)
Operator Monitoring
Where an acoustic booth/room is used, a patient microphone is connected
to the MIC2 input, while the operator headset/earpiece is connected to the
MONITOR output. The operator listening levels may be adjusted as
follows:
The level of the speech signal is controlled by the +Hz and -Hz keys,
giving 2dB steps
The level of the patient's responses is controlled by using the SIGNAL
rotary control while pressing and holding TALKBACK
Test Modes in Speech Audiometry
Initially in speech mode either ear may be selected, with the output level
controlled by the SIGNAL rotary control. Pressing TEST MENU followed
by Softkey 1 routes the speech to both ears (Stenger test with speech),
with the left output level controlled by the SIGNAL rotary control and the
right output level controlled by the MASK rotary control. Pressing TEST
MENU again returns to the original speech mode.