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Verifit User’s Guide Version 2.8
Page 52
9.6
Directional HIT procedure
FastFacts 9.6: Directional HIT procedure
9.7
Multicurve procedure
FastFacts 9.7: Multicurve procedure
Multicurve generates 1 to 4 output or gain response curves using either pink noise
or swept pure tones at input levels ranging from 40 – 90 dB SPL and 0 dB (off).
1)
Press <Tests>, then highlight and <PICK> [Multicurve].
2)
Refer to
7.11: Coupling the hearing instrument
,
7.12: Positioning the hearing
instrument
and
2.6: Battery pill use and care
to prepare the instrument for
testing.
Turn the instrument ON.
3)
Highlight and <PICK> button 1, 2, 3 or 4 in the Test column.
4)
Highlight and <PICK> the Stimulus window, then highlight and <PICK> either
[Pink noise] or [Swept] from the drop-down list.
5)
Highlight and <PICK> the Level window for the selected Test, then highlight
and <PICK> a stimulus level from the drop-down list.
6)
Press <Continue> to run a sweep or to capture a pink noise curve; press
<Cancel> to abort the test.
7)
To measure another response curve, highlight and <PICK> another test button;
to overwrite a curve, highlight and <PICK> its test button.
To change scale from dB SPL to dB Gain, highlight & <PICK> the Scale window.
To test directional function in the
test chamber
:
1)
Mount the hearing aid to the appropriate coupler (see
7.11: Coupling the
hearing instrument
).
2)
Position the hearing instrument in the test chamber as shown in
9.4: Directional
ITE positioning
or
9.5: Directional BTE positioning
.
3)
Press <Tests>, then highlight and <PICK> [Directional] from the HIT list.
4)
Highlight and <PICK> button 1, 2, 3 or 4 in the Tests column. This presents test
signals from both speakers. Two real-time curves appear on the screen - the
heavier one is the response to the left speaker signal and the lighter one the
response to the right speaker signal. For a non-directional instrument, the two
curves will be nearly identical. Setting the instrument for directional operation
should produce a separation of the curves. For an adaptive directional
instrument, the separation may change with time and stimulus SPL so vary the
level. For a noise-reducing instrument, both curves may change with time.
Curve separation
may
be reduced at high stimulus levels if the aid distorts.
5)
On the Test control poster, highlight and <PICK> the Level window, then
highlight and <PICK> a level from the drop-down list.
6)
Press <Continue> to capture curves or press <Cancel> to abort the test.
Captured curves are labeled
L
(
left speaker
response) and
R
(
right speaker
response) followed by the test number (1 - 4).
To test directional function in situ, see
12: Real-Ear Directional Test
