Audioscan Verifit 2 - Manual (Page 98)

Verifit ® User's Guide Version 4.2 © June 2015
microphone opening of the hearing instrument without touching it. Ensure the reference microphones are
positioned within the safe zone, as indicated by the lighter colored test box foam.
Coupling for ANSI tests
The Verifit is supplied with two blue-colored, metal, 2cc couplers, a type HA-1 (ITE) and a type HA-2 (BTE)
for ANSI test box tests, and two silver-colored 0.4 cc wide-band couplers for all other test-box tests. Note that
an ANSI standard coupler for CICs does not exist; these must be tested in the HA-1 coupler.
When connecting the couplers onto the binaural coupler microphone, it is important that they produce a good
acoustic seal. Ensure each coupler is fully inserted in the retention slot. To remove, push the red or blue levers
while pulling up on the coupler.
For all ANSI tests, the instruments are coupled to the blue (left) side of the binaural coupler microphone.
BTE instruments are coupled to the HA-2 coupler by means of a 9 mm length of black Viton tubing. The only
purpose of this tubing is to seal the tip of the earhook to the coupler inlet. All of the tubing required by ANSI
S3.22 is machined into the metal stem of the HA-2 coupler. The tubing should be inspected regularly for cracks
or stretching which will cause feedback.
Custom instruments are sealed to the HA-1 coupler with putty so that the end of the eartip is flush with the
inside of the coupler opening. Putty should not extend into the coupler cavity or block the sound outlet of the
instrument. Vents should be sealed at the faceplate end. It is very important that the instrument be well-sealed to
the coupler.
Open fit instruments must use the coupler and coupling system specified by the manufacturer. This may involve
a hook that replaces the open fit tubing or an adapter tube that may be sealed to the opening of the HA-1 coupler
with putty or by using the TRIC adapter where appropriate.
RITE (Receiver in the ear) instruments are coupled to the HA-1 coupler using the TRIC adapter, except where
otherwise required by the hearing instrument manufacturer.
Excess low frequency output is usually due to open vents or a poor seal to the coupler.
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