Frye FP35 Manual

A SERVICE OF

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72 FONIX FP35 Hearing Aid Analyzer

8. Press [EXIT] to return to the Coupler Multicurve screen.

9. Use [∨, ∧] to select the RMS source of the test. Each frequency will have an

amplitude 3 dB less than the RMS source.

10. Set up the aid for test in the sound chamber as usual. Make sure to close the

lid of the sound chamber.

11. Press [START/STOP] to perform the IM distortion sweep. See Figure 3.5.3

for an example. The percentage scaling for the measurement is located on

the right side of the graph. Notice the thick line below the lower right corner

of the graph. This is an indication that the current selected measurement

uses the right side scaling.

3.5.4 Changing the Frequencies of an IM Distortion Sweep

By default, the IM distortion sweep is performed at the frequencies used in the

NORMAL pure-tone sweep. This can be changed to perform the measurements

at fewer frequencies (for a faster test), and more frequencies (for a more com-

plete test). The USER LEVEL must be set to ADVANCED in the Default Settings

menu. See Section 2.3.2 for more details.

1. Press [MENU] from the Coupler Multicurve screen to enter the Coupler

Multicurve menu.

2. Press [NEXT] twice to enter the Custom Menu.

3. Use [ ∨, ∧] to select DISTORTION SWEEP.

4. Use [<, >] to make one of the following selections:

•NORM:Tomeasureat1/12octavefrequenciesclosestto100Hzintervals

(default test)

• FAST:Tomeasureat1/3octavefrequenciesclosestto100Hzintervals

(fastest test)

• FULL:Tomeasureatevery100Hzinterval(mostcompletetest)

5. Use the arrow keys to select DIST SWEEP END and choose the final fre-

quency in the IM distortion sweep.

6. Press [EXIT] to return to the Coupler Multicurve screen and follow the

directions in Section 3.5.3 to perform the IM distortion sweep.

3.5.5 Turning on/off Impulse Rejection

Impulse rejection can be used to reduce distortion caused by impulses in the

room noise. When noise reduction is used with IM distortion measurements,

several measurements are made to obtain the test results. See Section 2.5.2.2 for

more details. To change the impulse rejection settings, the USER LEVEL must be

set to ADVANCED. See Section 2.3.2 for more details.

1. Press [MENU] in the Coupler Multicurve screen to enter the Coupler

Multicurve menu.