natus Madsen A450, Руководство пользователя

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the same ear, masking is needed. The Masking Assistant can assist you in determining which thresholds need to be
masked.
If the SRT of the test ear and the bone conduction PTA of the nontest ear differ by 45 dB or more, masking is needed.
Mastoid placement
1. Move any hair covering the mastoid out of the way and place the flat round part of the bone conductor securely on
the boniest portion of the mastoid without any part of the transducer touching the external ear.
2. Make sure the bone conductor is tight on the mastoid but still comfortable.
3. If you are going to perform masking with earphones, position the other end of the bone conductor headband over the
patient's temple on the opposite side of the head so that the headband of the earphones and bone conductor fit on
the patient's head.
Loudspeaker placement
The environment in which sound-field audiometry is performed may affect the sound field near the patient.
The performance of loudspeakers for Madsen A450 was tested by Natus under free-field conditions in a large anechoic
chamber. Sound pressure level, frequency response and distortion were measured by a microphone placed 1 m from the
front of the speaker.
When speakers are installed in other types of environment, the characteristics of the resulting sound field should be eval-
uated by qualified personnel.
12 Performing tone audiometry
A.
Menu bar
B. Audiometry toolbar
C. Stimulus bar
D. Control panel
E. Work area
F. Feature boxes
Whenever the test buttons and other functions are used, you can use the corresponding keys on the keyboard, or the on-
screen controls located at the top of the screen or in the Control Panel to the left.
For detailed examples of audiometric testing, see the Madsen A450 Reference Manual.
1. Select the
Tone
screen in the Otosuite Audiometry module.
Madsen A450 17
12 Performing tone audiometry