15
Section 1: Coupler Tests of FM Systems
g. You may want to press [
∨
] and [FREEZE] to turn off the display of CRV 3, since
it is not relevant to this comparison. Similarly, press [
∨
] and [FREEZE] again to
turn off the display of CRV 4.
If you don’t have the Multi-Curve Option, press [CRT] to print out EFE90 and com-
pare it to EHA90.
5. If EFM90 is greater than 5 dB above or 10 dB below EHA90, adjust the maximum
output control if possible on the FM receiver or on the hearing aid if necessary. If the
hearing aid is adjusted, the teacher, parents, and therapists must be made aware that
when the FM system is used, the settings on the hearing aid must be changed for
optimum performances. For mild to moderate losses it may be acceptable if the
EFM90 is 5-10 dB below EHA90. See Figure 1.2.4.