Frye FONIX FP40D - Manual (Page 126)

118 FONIX FP40 Portable Hearing Aid Analyzer
6. Use F3 to select AIDED 1.
7. Place the hearing aid in the ear. The aid should be turned off.
8. Push the START/STOP button. Instruct the client to sustain the vowel sound “ee.”
9. While the “ee” is still sounding, and once the curve on the screen has stabilized, press
START/STOP. Note the total RMS Output in the ear canal as indicated in the status box.
10. If the SPL seems high, you might modify the vent size. Use F3 to select AIDED 2 and repeat
steps 6 and 7. If your changes have been successful, you should see a lessening of total RMS
Output. AIDED 2 should be less than AIDED 1.
Note: You could also measure the effects with the hearing aid turned on.
Figure 10.3
A PPLICATION 2: I NSERTION G AIN M EASUREMENTS U SING AN E XTERNAL S OUND S OURCE .
For this procedure the choice of sound source is yours. You may want to use a tape or CD player
through a loudspeaker. Any sustained sound source will work. Whether you use a cocktail noise
tape or one of the new environment CDs, you should find your test results interesting, especially
when testing nonlinear signal processing hearing aids.
Suggested Procedure:
1. Prepare your sound source.
2. Press F5 from the Main Coupler screen to enter the Probe Mode.
3. Use F2 to select IG.
4. Use F7 to select a source type of COMPOSITE.
5. Use the AMPLITUDE knob to turn the source all the way OFF. This puts the analyzer in
Spectrum Analysis Mode.
6 Perform a typical UNAIDED and AIDED real-ear test, except use “your external sound source”
instead of the composite signal.