68 FONIX FP40 Portable Hearing Aid Analyzer
Follow the instructions from Section 3.3 to set up the aid in the test box for testing.
4.5.2 Setting up the analyzer for testing
To enter the IEC screen:
1. From the Main Coupler Screen, look at the FP40’s display above the F4 function key. If it says
“IEC” skip to step 6.
2. Press F1 – Menu.
3. Use the AMPLITUDE and FREQUENCY knobs to select MAIN F4 under FUNCTION KEY
DEFIN.
4. Press START/STOP to choose IEC. This will let you use the F4 function key to enter the IEC
screen from the Main Coupler Screen.
5. Press F1 to return to the Main Coupler Screen.
6. Press F4 to enter the IEC screen.
To change IEC
settings:
1. Press F2 to choose the source level for full-on gain measurements and whether or not you
would like to take an I/O measurement. type of aid you are testing. The selections are AGC
50, LINEAR 50, LINEAR 60.
• Choose 60 for most linear aids.
• Choose 50 for high-gain linear aids.
• Choose I/O 60 for AGC aids with the AGC circuit disabled
• Choose I/O 50 for most AGC aids
Note: If you are testing a digital aid, you should usually select I/O 50 for this setting.
However, ask the hearing aid manufacturer for guidance.
2. Press F3 to set the reference test frequency. If possible, use the frequency recommended by
the manufacturer. Otherwise, use 2500 Hz for high frequency emphasis aids and 1600 Hz for
all other aids.
3. Press F5 to select the harmonic distortion test frequency.
4. Press F6 to select the noise reduction used to take the measurements.
5. Press F7 to select the battery type.
6. Press F8 to select whether or not you want to perform an equivalent input noise (EQIN also
known as EIN) measurement.
Note: The equivalent input noise measurement is difficult without a very quiet environment,
especially with low gain aids.
7. Decide whether you want to test with or without the reference microphone. See Section 3.4.9
for more information.
