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

Coupler Measurements 24
6. Use [F5] to select DIG SPEECH as the signal source. This serves to provide a
reference point for the measures that follow.
7. Use the up and down arrows to select an amplitude approximating normal
speech, such as 60 dB SPL.
8. Press [START] to begin the measurement.
9. When the curve has stabilized press [STOP].
10. Press [F2] to select the second curve (CRV 2).
11. Press [MENU] to enter the
Coupler menu. Press the
down arrow to select Bias
Tone under the Source
Settings heading. Use the
right arrow to select a bias
tone amplitude. An
appropriate amplitude is
commonly 55 dB SPL. The
bias tone is now turned on.
Options for bias tone amplitude
include OFF and from 40 to 90 dB
SPL, in 5 dB increments.
12. Press [EXIT] to return to the coupler test screen.
13. Use the right and left arrow keys to vary the frequency of the bias tone.
Options for bias tone frequency range from 200 to 8000 Hz in varying increments.
14. Ensure that the signal amplitude is 60 dB SPL and that DIG SPEECH is
selected as the signal source. Press [START] to begin the measurement.
15. When the curve has stabilized press [STOP].
Figure 30 – Coupler Menu Options
16. Use [F2] to select another curve for testing at another bias tone frequency.
17. Repeat steps 13 through 15 for testing at additional bias tone frequencies,
ensuring that the signal amplitude remains 60 dB SPL and the signal
source remains digital speech.