Maico MA 42 Operation Manual

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Maico MA 42 Operation Manual Manual pdf 26 page image

Operation Manual MA 428100460 Rev.7 Ver.1 21 12/15Automatic MaskingWith the manual masking, as described above, the masking level should beadjusted every time you change the test signal level. The MA 42 has atracking function for easy masking.Set the tone level and the masking level to a desired difference for effectivemasking. Press the Track button (14) to implement the automatic maskingfeature. The masking level is automatically changed if you adjust the testsignal level (e.g. if the test level is at 30 dBHL and the masking level 50 dBHLand you change the test level to 45 dBHL the masking level will automaticallyadjust to 65 dBHL).6.1.2 High Tone Audiometry (optional)When available, pure tone hearing threshold of high frequencies from 8 kHzto 16 kHz can be tested. The High Tone option must be activated and aseparate high tone transducer must be calibrated for all frequencies.First select the corresponding output Phones by the button (10) or (16). Theitem High Tone is now available at the functional button (13). Select HighTone 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 thefrequency Up (4) or Down (5) key. The test procedure is identical to thedescription in chapter Pure Tone Testing.If a transducer is selected which is not calibrated for high frequencies, thestandard diagram will be displayed and high frequencies will not be available.On the printout, pure tone audiometry results will appear in a high tonediagram combining left and right ear results.6.1.3 Bone Conduction TestingBone conduction - the transmission of sound waves through the skull directlyto the inner ear - provides information about the function of the inner ear. Fora neural hearing loss the values of air conduction and bone conduction arethe 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 thetransducer is placed on the mastoid, at the noticeable ledge of the cranialbone behind the pinna. The other side of the headband is placed in front ofthe opposite ear.Set the receiver selector to Bone (10) or (16) and the signal selector to Tone(11) or (15).