Audioscan Verifit - Manual (Page 43)

Verifit ® User's Guide Version 3.12  May 2015
9. Highlight, then <PICK> [Start test] (which changes to [Stop test]).
10. Check that the Coupler microphone level is within 1 dB of the calibrator level setting, +/- the calibrator
accuracy. For a 94 dB calibrator with +/- 0.3 dB accuracy, the indicated coupler microphone level should be
94 +/- 1.3 dB.
11. To stop the measurement, highlight and <PICK> [Stop test].
Coupling the hearing instrument for ANSI tests
The Verifit is supplied with 2 metal couplers, a type HA-1 (ITE) and a type HA-2 (BTE). Note that an ANSI
standard coupler for CICs does not exist. These must be tested in the HA-1 coupler.
When threading the couplers onto the coupler microphone, it is very important that they be firmly tightened to
ensure a good acoustic seal. Avoid twisting the coupler microphone cable – turn the coupler not the microphone
or unplug the microphone while tightening the coupler.
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 HA-2 coupler tubing should be inspected
regularly for cracks which will cause feedback. If the tubing is worn or damaged, contact Audioscan for a
replacement. Alternatively, it can be replaced by a 10 mm length of #13 heavy wall earmold tubing.
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.
RITE (Receiver in the ear) instruments are coupled to the HA-1 coupler using putty to seal the receiver module
or soft tip to the coupler opening.
Excess low frequency output is usually due to open vents or a poor seal to the coupler.
For health reasons, hearing instruments should be clean before putty is applied and putty should be replaced
frequently.
Coupling the hearing instrument for Test box Speechmap
The ANSI S3.46-2013 standard specifies RECD referenced to the HA-1 coupler and suggests its use in test
box verification for all instrument types. Audioscan software allows for BTE coupling to either HA-1
through earmold, or HA-2 with a software correction.
BTE instruments may be coupled either directly to the HA-2 (BTE) coupler, or to the HA-1 coupler using
the client’s earmold and blue putty. When using the earmold, ensure that the mold is well-sealed to the
coupler and that the medial end is flush with the inside of the coupler opening. Putty should not extend into
the coupler cavity or block the sound outlet. Vents should be sealed at the lateral end. Coupling method
used for BTE instruments (HA-2 or HA-1) must be specified in Instrument type selection on Speechmap
screen. See Using Speechmap, RECD
Custom instruments are sealed to the HA-1 coupler with putty so that the end of the eartip is flush with the
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