Basic Sound Chamber Tests 61
4. Seal any vent on the aid with a small
kernel of Fun-Tak.
5. Complete the acoustical sealing of
the aid to the coupler by using a pen-
cil or finger. You may want to dou
-
ble-check the aid placement through
the open end of the coupler at this
point. Slowly reinsert the coupler
microphone into its access opening.
6. Place the completed assembly at the
reference position in the test cham
-
ber. With ITEs, the position of the aid
can affect the frequency response.
As a rule, point the faceplate of the
aid toward the right, with the micro
-
phone opening as close as possible
to the reference circle. It is best,
when possible, to angle the faceplate
upward instead of downward (see
the photo at left).
For the sake of repeatability, you may
elect to use a ninety degree angle of
the faceplate to the reference circle,
again with the microphone opening
as close as possible to the reference
circle. If you are using a battery pill,
be sure the metal conductor strip
does not obstruct the sound path.
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