Frye FONIX 7000 User Manual

Page 158

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FONIX 7000 Hearing Aid Analyzer

another measurement curve. It is recommended to perform real-ear measure-
ments as 50, 65, 80, and 90 dB SPL. For this reason, the default source levels of
REAG 2-5 are set accordingly. Use the up-down arrow keys to change the select-
ed source amplitude at any time.

6.4.5 Working with prescription targets

The 7000 Hearing Aid Test System has the following fitting rules available:
NAL-NL1, NAL-RP, 1/3 Gain, 1/2 Gain, 2/3 Gain, Berger, and POGO. The NAL-
NL1 fitting rule is non-linear and changes depending upon the amplitude of the
input signal. The other fitting rules are linear and provide the same amount of
gain regardless of the input level.

To display a target, the clinican must enter the patient’s audiogram in the
Audiogram Entry screen. See Section 6.3.1. Values must be entered at 500, 1000,
2000, and 4000 Hz or the target will not be displayed.

The NAL-NL1 target has a number of settings associated with it that will change
the prescription. Press [MENU] in the Audiogram Entry screen, Insertion Gain,
or Real-ear SPL screen to change the current settings. Press [EXIT] to close the
local menu when the changes are complete.

In the Insertion Gain screen, one insertion gain target is displayed in the top
graph. If the NAL-NL1 fitting rule is selected, this target adjusts according to the
input level setting of the current selected curve. That is, if the amplitude of the
source is set to 50 dB SPL, the displayed target is for a 50 dB SPL input level.
If the clinician changes the input level to 80 dB SPL, the target will decease,
showing the prescription for that input level. When the unaided (REUG 1) is
selected, the target curve uses the source settings for REAR 3.

In the Real-ear SPL screen, up to three SPL targets are displayed on the screen.
When NAL-NL1 is the selected fitting rule, all three targets are automatically
displayed. They are labeled L, M, and H. The L target is tied to the input level
and speech weighting selected for REAR 2. The M target is tied to the input
level and speech weighting selected for REAR 3. The H target is tied to the input
level and speech weighting selected for REAR 4. That is, if the clinican changes
the input level or speech weighting of REAR 2, 3, or 4, the corresponding SPL
target will also adjust.

If a fitting rule other than NAL-NL1 is selected, only the M target is displayed,
which is tied to REAR 3. If desired, the clinican can turn on the display of the
other two targets using [F3], but these targets will be linearly related to each
other. That is, unlike with the NAL-NL1 non-linear target, the shape of the lin-
ear target will not change as the input level of the input signal changes.

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