48
Testing FM Systems with FONIX 6500-CX Analyzers
6. This curve will be referred to as the Real-Ear FM Response or RFM80. See Figure
2.2.2.
7. Compare RHA65 (CRV 1) to RFM80 (CRV 2). If you have a child with a mild to
moderate hearing loss (less than 80 dB HL), the output of the two curves should be
within 5 dB of each other. If you have a child with a severe to profound loss (greater
than 80 dB HL), the output of EFM80 should be 7-10 dB higher than the output of
EHA65.
To obtain a better match, first adjust the FM volume control. As a last resort, adjust
the settings on the hearing aid and inform the teacher, parents, and therapists that
when the FM system is used, the settings on the hearing aid must be changed for
optimum performance.
2.2.3 Test aid with high-level input—RHA90
1. If you followed the instructions from Sections 2.2.1 and 2.2.2, you will be in the SPL
Test Screen.
2. Press
[MENU].
3. Select PT_BURST for AIDED CURVE 1 and AIDED CURVE 2.
4. Press [MENU] to return to the SPL Test Screen.
5. Follow the instructions found in Section 2.1.1 to set the client up for a real-ear hear-
ing aid measurement and level the sound field.
Figure 2.2.3
RHA90-real-ear saturation response of the hearing aid
