Coupler Measurements 59
Figure 3.2.1—Normal leveling setup
3.2.1 Leveling without the Reference Microphone (Standard)
Leveling the sound chamber using only the measurement microphone is accu-
rate enough for most clinical tests.
1. Enter the Coupler Multicurve screen by pressing [F3] in the Opening screen.
2. Open the sound chamber and place the coupler microphone at the center of
the speaker cone in the sound chamber.
If the microphone cables are not positioned properly, the chamber lid can
pinch, and eventually damage them. Avoid damage by placing the cables
between the arrows at the bottom of the speaker face. The foam on the
chamber lid is thicker and softer in this area, offering more protection.
3. Place the coupler that you will be using inside the chamber next to the cou-
pler microphone. This is necessary because of the small volume of the FP35
internal sound chamber, and measurement results, particularly in the high
frequencies, could be affected by the space the coupler takes up inside the
chamber. See Figure 3.2.1.
4. Close the sound chamber lid.
5. Make sure the environment is as quiet as possible.
6. Press [F5], followed by [START/STOP], to level the sound chamber.
7. Follow the instructions in Section 3.2.3 to save the leveling, if desired.
Note: When testing, make sure the hearing aid microphone is located where
the grill of the measurement microphone was placed during the leveling pro-
cess (usually at the center of the speaker cone in the sound chamber). This will
increase accuracy through the low frequency range.
