Audioscan Verifit 2 - Manual (Page 111)

Verifit ® User's Guide Version 4.2 © June 2015
To test directional function in situ, see On-Ear Instrument Measures
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).
Multicurve allows the use of the 2cc HA-1 coupler or the 0.4cc Audioscan Wideband Coupler (AWC). The
HA-1 coupler is not useful at high frequencies because of resonances and low signal levels. The use of the
AWC is desirable because it raises the high frequency SPL of the hearing aid by more than 20 dB, making the
rising noise floor of the coupler microphone less significant.
1. Open the home menu using the right mouse button. Select [Multicurve] from the Test box list.
2. Refer to Coupling the hearing instrument, Positioning the hearing instrument for testing.
3. Turn the instrument ON.
4. Click button 1, 2, 3 or 4 in the Test column.
5. Click Stimulus and select either [Pink noise] or [Swept] from the drop-down list.
6. Click on the Level window for the selected Test and stimulus level from the drop-down list.
7. Click to run a sweep or to capture a pink noise curve; click to abort the test.
8. To measure another response curve, click another test button; to overwrite a curve, click its test button.
To change scale from dB SPL to dB Gain, highlight and select the Scale window.
Multicurve results
1. Output curves for the noise signal are in 1/12th octave bands. They will be approximately 19 dB lower than
pure tone curves for a linear instrument.
2. Gain curves for a linear instrument will be the same for both swept and pink noise test signals.
3. For compression instruments, both gain and output curves may be expected to differ for the two test signals.
4. See Test Box Measures - Setup to change screen appearance.
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