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Section 2: RealEar evaluation with FM system
3. Put the reference microphone on the wedge above the client’s ear so that it points
towards the sound field speaker. See Figure 2.1.1.
4.
Press [LEVEL] on the remote module. This will level the sound field speaker.
5. Mark the probe tube to ensure the desired insertion depth, and place it into the
client’s ear.
6. Carefully insert the earmold attached to the hearing aid.
7. You are now ready to test the hearing aid.
2.1.2 FM System
When testing the transmitting and receiving part of the FM system in the real-ear, the FM
transmitting microphone is placed in the sound field. The probe microphone and the ear
piece of the FM receiver are inserted into the client’s ear, but the client remains outside of the
sound field. Since FM measurements follow hearing aid measurements in all of the
described sets of tests, it is assumed that the analyzer is already in Real Ear Mode.
1.
Place the reference microphone on a platform at the top of a floor stand, 6 inches (15
cm) in front of and facing the loudspeaker, as in Figure 2.1.2A.
2.
Choose a place to stand during testing, preferably away from the loudspeaker and
microphone. Hold the remote module, so you can operate the test. Stand precisely in
this place during both leveling and testing.
3.
Press [LEVEL] on the remote module. This levels the sound field.
4.
Remove the reference microphone and replace it with the FM transmitting micro-
phone.
5
Mark a probe tube attached to the probe microphone to ensure the desired insertion
depth, and place the probe tube and the ear piece of the receiving unit in the client’s
ear. The insertion depth of the probe tube should be the same as used to test the
client’s hearing aid The client should be at least 2 ft (60 cm) from the loudspeaker to
avoid being in the sound field. See Figure 2.1.2B.
6. You are now ready to test the FM transmitter/receiver.
