Frye FONIX 7000 - Manual (Page 94)

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FONIX 7000 Hearing Aid Analyzer
Figure 3.5.3—Using the bias signal with Digital Speech. CRV 1-3 have bias signals at 500 Hz,
1000 Hz, and 4000 Hz respectively. CRV 4 was performed with Digital Speech and no bias signal.
7. Use [<, >] to change the frequency of the bias signal. The current selected
frequency will be displayed on the screen below the Curve Characteristics
Box.
8. Press [STOP] when done with the measurement. See Figure 3.5.3 for an
example of using the bias signal at several different frequencies.
3.5.4 Checking Noise Suppression
When testing a digital hearing aid that is supposed to be programmed with a
noise suppression or speech enhancement feature, it is useful to make sure the
feature is working correctly. You can use a combination of Digital Speech and
the Composite signal to test noise suppression.
1. Look at the top left corner of the graph on the Coupler screen. It should
read “dB GAIN.” If it reads “dB SPL,” you will need to change the display to
GAIN. To do this:
a. Press [MENU] from the Coupler screen to open the local menu.
b. Use [∨, ∧] to select Display under Display Settings.
c. Use [<, >] to choose GAIN.
d. Press [EXIT] to return to the Coupler screen.