Maico MA 42, Руководство по эксплуатации

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Operation Manual MA 42
8100460 Rev.7 Ver.1 21 12/15
Automatic Masking
With the manual masking, as described above, the masking level should be
adjusted every time you change the test signal level. The MA 42 has a
tracking function for easy masking.
Set the tone level and the masking level to a desired difference for effective
masking. Press the Track button (14) to implement the automatic masking
feature. The masking level is automatically changed if you adjust the test
signal level (e.g. if the test level is at 30 dBHL and the masking level 50 dBHL
and you change the test level to 45 dBHL the masking level will automatically
adjust to 65 dBHL).
6.1.2 High Tone Audiometry (optional)
When available, pure tone hearing threshold of high frequencies from 8 kHz
to 16 kHz can be tested. The High Tone option must be activated and a
separate high tone transducer must be calibrated for all frequencies.
First select the corresponding output Phones by the button (10) or (16). The
item High Tone is now available at the functional button (13). Select High
Tone by pressing the functional button (13) until High Tone is highlighted.
The high tone diagram is displayed, combining the left and right ears results.
Additional frequencies from 8 kHz to 16 kHz can be selected now by the
frequency Up (4) or Down (5) key. The test procedure is identical to the
description in chapter Pure Tone Testing.
If a transducer is selected which is not calibrated for high frequencies, the
standard diagram will be displayed and high frequencies will not be available.
On the printout, pure tone audiometry results will appear in a high tone
diagram combining left and right ear results.
6.1.3 Bone Conduction Testing
Bone conduction - the transmission of sound waves through the skull directly
to the inner ear - provides information about the function of the inner ear. For
a neural hearing loss the values of air conduction and bone conduction are
the same. In this case a hearing loss of the middle ear can be eliminated.
Place the bone conduction oscillator so that the flat, circular side of the
transducer is placed on the mastoid, at the noticeable ledge of the cranial
bone behind the pinna. The other side of the headband is placed in front of
the opposite ear.
Set the receiver selector to Bone (10) or (16) and the signal selector to Tone
(11) or (15).