Table of Contents
Advertisement
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.
For health reasons, hearing instruments should be clean before putty is applied and putty should be replaced
frequently.
Positioning HI for ANSI/IEC tests
1. The hearing instrument should be coupled to the appropriate blue coupler and a battery pill or battery
installed. See Coupling the hearing instrument for ANSI tests.
2. Place the instrument and coupler in the test chamber so that the microphone opening(s) of the instrument are
on the crossbar within the test zone.
3. For directional instruments, the direction of maximum sensitivity should be oriented toward the speaker.
4. Position the test box reference microphone as close as possible to the (front-facing) microphone opening of
the hearing instrument without touching it.
5. Close and seal the test chamber.
Verifit
®
User's Guide Version 4.8 © November 2016
Positioning a BTE instrument for ANSI tests
101
Advertisement
Table of Contents
