Automated Test Sequences 103
4.2.4 Running an IEC Test
1. Level the sound chamber as described in Section 3.2, if needed.
2. Push the [START/STOP] key.
3. The FP35 will pause during the measurement process in order to let you
adjust the gain of the hearing aid to the reference test position.
a. Lift the sound chamber lid and adjust the gain control of the aid until the
MEASURED gain matches TARGET gain.
b. Close the sound chamber lid when finished.
c. The MEASURED gain should be within 1 dB of the TARGET gain.
4. Push [START/STOP] to complete the test.
5. Press [NEXT] to view the I/O Screen if the aid type was set to AGC or
Adaptive AGC.
6. Press [PRINT] for a hard copy of the results.
4.2.5 Defining the Menu Items
There are two menus for the IEC Screen. The first contains the most basic items;
things you may want to change frequently. The Advanced Menu contains more
advanced features that most users probably don’t need to worry about.
Main IEC Menu
Open the main IEC Menu by pressing [MENU] from the IEC Screen.
EQ INPUT NOISE—The type of equivalent input noise measurement (EIN)
made with the IEC test. NORMAL sets the EIN to use the entire 200 Hz—8000
Hz frequency band. A selection of 5KHz sets the frequency band to 200 Hz—
5000 Hz (recommended), and a selection of OFF skips the EIN entirely.
DISTORTION FREQ—The frequency used to take the harmonic distortion test.
NOISE RED— The amount of noise reduction used for the pure-tone measure-
ments. See Section 2.5.1.3.
REF MIC— The status of the reference microphone.
Advanced IEC Menu
Reach the following menu choices by pressing [NEXT] while the IEC Menu is
open.
PREDELAY TIME—The delay after the first tone is presented and before the first
measurement is taken. See Section 2.4 for more information.
SHORT SETTLE—The time delay between the frequencies of pure-tone sweeps and
input/output curves.
