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Testing FM Systems with FONIX 6500-CX Analyzers
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Testing FM Systems with FONIX FP40 Analyzers
1.4 Coupler Setup in the Sound Field
When testing a FM system with a large or directional microphone, the measurements are
performed in the sound field. Therefore, the corresponding hearing aid tests will also have
to be performed in the sound field. This requires a little creativity; you may have to adjust
the following recommended procedure to fit the particular equipment that you are testing.
1.4.1 Hearing Aid Setup
1. Enter the Real Ear Mode by pressing [START/STOP] on the remote module. All fur-
ther key presses described in this section will be performed on the remote module.
2. Affix the reference microphone with Fun-Tak to the platform at the top of the floor
stand, 6 inches (15 cm) in front of the sound field speaker, with the microphone
pointing toward the speaker. See Figure 1.4.1A. (If you don’t have a floor stand, the
back of a chair can suffice. But be sure the chair is facing to the side of the setup to
avoid reflections from the back of the chair.)
Figure 1.4.1A
Sound field leveling setup
3.
Stand clear of the test area, holding the remote module.
4.
Press [LEVEL] on the remote module.
5. Remove the reference microphone and the platform from the floor stand, leaving the
floor stand in its position in front of the sound field speaker.
6. Attach the hearing aid to the HA-2 coupler.
6 inches
Reference mic
Probe mic
(not used)