FONIX® 8000 - Frye Electronics

66 FONIX 8000 Hearing Aid Test System
3.4.3 Example
Following the instructions above, run 4 Gain curves using amplitudes 50, 60,
70, and 80 dB SPL. Use a signal source of COMPOSITE.
This scenario will provide you with a family of curves. Whenever the curves sit
on top of each other, the gain of the aid is the same for the amplitudes of those
curves. This indicates the aid is running linearly. If the curves provide progressively
less gain as the input rises, then the aid has some sort of compression
circuit. Figure 3.4.3 shows two examples of this scenario.
Here are the steps:
1. Look at the graph. If it has a display of SPL, press [MENU] and change the
DISPLAY from SPL to GAIN, using the arrow keys. Press [EXIT] to return to
the Coupler screen.
2. Use [F2] to select CRV 1. (Press [F2]. Use [, ] to select CRV1. Press [] to
complete the selection and close the pop-up window.)
3. Use [, ] to select a source level of 50 dB SPL.
4. Use [F5] to select a source type of COMPOSITE.
5. Press [START] to run the first measurement. Press [STOP] when the measurement
has stabilized.
6. Use [F2] to select CRV 2.
7. Use [] to select a source level of 60 dB SPL.
8. Use [F5] to select a source type of COMPOSITE.
9. Press [START] to run the second measurement. Press [STOP] when the measurement
has stabilized.
10. Use [F2] to select CRV 3.
11. Use [] to select a source level of 70 dB SPL.
12. Use [F5] to select a source type of COMPOSITE.
13. Press [START] to run the third measurement. Press [STOP] when the measurement
has stabilized.
14. Use [F2] to select CRV 4.
15. Use [] to select a source level of 80 dB SPL.
16. Use [F5] to select a source type of COMPOSITE.
17. Press [START] to run the fourth measurement. Press [STOP] when the measurement
has stabilized. You now have a family of curves.