Using the FONIX 7000 to Verify Coupler and Real-Ear Performance ...

Real Ear Measurements 34
2.3 Measuring the real ear front-to-back ratio in order to determine the efficacy of
directional microphones. This measure is easy to perform at the completion of
insertion gain verification or may be performed as a separate measure.
STEP-BY-STEP
Front
Back
Back
Figure 43 – Real ear insertion gain measurement of front-to-back ratio
1. Press [F2] from the Opening screen to enter the Real Ear Navigation screen.
2. Press [F3] to enter the Insertion Gain screen.
3. Use [F1] to select the test ear.
4. Following otoscopic inspection, insert the probe tube in the test ear 6 mm from
the tympanic membrane as described in the “Basic Overview of Preparations for
Real Ear Measures.”
5. Place the sound field speaker at a distance of approximately 12 inches from the
client’s head at 0° azimuth (directly in front of the patient) from the test ear. The
height of the sound field speaker should be level with the test ear.
6. Insert the hearing aid into the test ear, taking special care not to move the probe
tube.
7. Use [F2] to select REUG 1. Ensure that the source amplitude is 65 dB SPL and
use [F5] to ensure that a modulated source is selected (DigSpeech).
8. Press [START] to begin measurement and press [STOP] when the curve is
present.