Audioscan Axiom - Manual (Page 44)

Axiom ® User's Guide Version 1.8  May 2015
2. Screw the appropriate calibrator ring onto the coupler microphone.
3. Insert the coupler microphone with the attached calibrator ring into the calibrator opening.
4. Turn the calibrator on and adjust it to present one of the available frequencies and levels (e.g., 94 dB SPL at
1000 Hz).
5. Click on , and click on [Manual control] in the Test box menu.
6. Click the [Level] button and click on '0' on the drop-down list.
7. Click the [Frequency] button and highlight and click the frequency of the calibrator (e.g. 1000 Hz) on the
drop-down list.
8. Click the [Filter] button and click on 1/12th octave from the drop-down list.
9. Click [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, click [Stop test].
Coupling the hearing instrument for ANSI tests
The Axiom 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.
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