Audioscan Verifit 2 - Manual (Page 101)

Verifit ® User's Guide Version 4.2 © June 2015
16 ANSI Hearing Aid Tests
These tests follow the procedures of the ANSI S3.22-2003 standard:
Linear: An automated test sequence for linear hearing aids per ANSI S3.22.
AGC: An automated test sequence for AGC hearing aids per ANSI S3.22.
Input/Output: 1 - 4 curves of coupler SPL vs input SPL at .25, .5, 1, 2 and 4 kHz.
Telecoil: Tests for telephone sensitivity and test loop sensitivity using a telephone magnetic field simulator
(TMFS) and a large coil in the test chamber floor.
ANSI S3.22-2003 facts
ANSI S3.22-2003 has been designated a recognized standard by the FDA and is mandatory for reporting test
data.
The most significant change from the 1996 version is the requirement for the hearing aid to be set in its most
linear mode for the setting of the gain control to Reference Test Setting (changed from Reference Test Position)
and for all tests except attack and release and input-output (I/O) curves. These two tests are to be conducted with
the AGC function set for maximum effect. The AGC test sequence will pause to allow AGC to be set prior to
measuring attack and release time.
Full-on gain is determined with 50 dB input SPL (60 dB was formerly an option) and frequency response curves
are run at 60 dB SPL for Linear and AGC aids.
The OSPL90 curve, the HFA (or SPA) and peak value of this curve, the frequency of the peak, the HFA (or
SPA) full-on gain are determined at full-on gain setting. The response curve, frequency range, Reference Test
Gain, battery drain, equivalent input noise, distortion, attack and release times are determined at RTS.
These changes result in more consistent values for reference test gain, equivalent input noise and attack and
release time. See 2003 ANSI standard, and 8.5: ANSI 2003 Linear and AGC tests.
ANSI 2003 Linear and AGC tests
1. Click the right mouse button to raise the home menu, then select [Linear] or [AGC].
2. Click [Start test] and follow the test setup instructions which are presented.
3. Refer to Test Box Measures – Setup, Coupling the hearing instrument, Positioning the hearing instrument
and Battery pill use and care to prepare the instrument for testing.
4. Turn the instrument ON.
5. Set the gain control (manual or programmable) to maximum with all other controls set to provide the widest
frequency response, greatest gain and highest maximum output. AGC controls and/or programmable
parameters should be set to minimize AGC action (AGC off or threshold high, compression ratio close to 1).
6. Click to run the test or click to abort the test. Note that, if required, the Verifit will pause during
the test to request that the gain control be adjusted to the Reference Test Setting (RTS). If necessary, open
the test box and, without moving the hearing instrument, adjust the gain control until the large vertical arrow
on the screen prompt disappears. Press
to resume the test.
During the AGC test, the Verifit will pause to request that AGC controls or programmable parameters be set for
maximum AGC effect. If the manufacturer does not provide settings to produce maximum AGC effect, use
settings that result in the highest gain for soft sounds and the lowest gain for loud sounds. This will typically
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