Coupler Measurements 81
Figure 3.8.3—Testing using the reference microphone
If you choose to use the reference microphone, you should use the leveling pro-
cedure described in Section 3.2.2.
1. Press [MENU]
2. Select REF MIC using the [∨, ∧] keys.
3. Set REF MIC to ON using [<, >] keys.
4. Press [EXIT] to exit from menu.
5. Set up the aid as described in Section 3.3.
6. Place the tip of the probe microphone as close as possible to the hearing aid
microphone without touching it.
7. Test as usual.
Caution: If you set the reference microphone ON, you must use it to run tests. If
you do not, the instrument will return erroneous results.
3.8.4 Reversing the Microphones
In normal operation, the coupler microphone functions as the “measurement”
microphone. It takes measurements and, if the reference microphone is on, com-
pares these measurements to the reference microphone.
It’s possible that you might encounter a situation where you want to perform
a measurement in the Coupler Multicurve screen, but the coupler microphone
is too large or somehow otherwise unsuitable for the particular function. If you
have the M300 two-microphone setup on your FP35, you can “reverse” the
microphones in Coupler Multicurve screen so that the probe microphone works
as the “measurement” microphone and the coupler microphone works as the
“reference” microphone. The USER LEVEL must be set to ADVANCED in the
Default Settings menu. See Section 2.3.2 for more details.
