3. Position the reference microphone (1) pointing straight down from
above and centered 1-2 millimeters above the coupler meas-
urement microphone (3).
4. During calibration the microphones must have the exact same dis-
tance to the main loudspeaker (2), along the Z axis. You can ensure
this by looking at the test chamber from the side when you adjust
the reference microphone position for calibration.
5. Close the lid.
6. Select
Tools
> AURICAL HIT
Calibration
>
Reference Microphone
.
7. Follow the on-screen instructions.
3.2
Positioning the hearing instrument for testing
How you position the hearing instrument for testing in the test chamber depends on the type of hearing instrument or
device you wish to test.
Regardless of form factor (the type of hearing instrument), the only two important things to remember are:
•
Aligning directional microphones along the loudspeaker axis.
•
Positioning the reference microphone as close as possible to the front microphone of the hearing instrument without
touching it.
Single-microphone omni mode:
If the hearing instrument is not capable of single-microphone omni mode, it is recommended that you position the
hearing instrument at a 90° angle so that the distance is the same between the AURICAL HIT main loudspeaker and
the two hearing instrument microphones.This also means that you must reposition the hearing instrument in the
standard position before directional measurements are performed.
3.2.1
General guidelines for positioning the hearing instrument
The absolute position of the hearing instrument is not critical, as long as the reference microphone is correctly positioned.
You can position the hearing instrument to perform all standard hearing instrument tests without repositioning the hear-
ing instrument between the individual tests:
•
acoustic measurements,
•
inductive telecoil measurements,
•
directional microphone test.
1.
Positioning the hearing instrument
–
Angle or turn the hearing instrument so that the front microphone (1) faces the main loudspeaker as it would
when worn on a person’s ear.
16
Otometrics - AURICAL HIT
3 Testing hearing instruments
