FONIX® 8000 - Frye Electronics

194 FONIX 8000 Hearing Aid Analyzer
• System UNLEVELED
• Reference microphone OFF
• Unaided CUSTOM
• Probe microphone over the bad ear,
tube jutting just slightly forward of
pinna
• Loudspeaker at 90º, 12 inches from bad ear
aided—Real Ear response on “good” ear side
Same setup as above except:
• Probe microphone over the good ear
The difference curve, labeled “Insertion
Gain” on the screen, shows the attenuation
of sound arriving at the good ear from
the bad ear side. Since this measurement
excludes the external ear, differences
across individuals should be minimal.
note: Although the above two measurements calls for the 8000 test system to
be UNLEVELED with the reference microphone OFF, the rest of the measurements
in this section call for the 8000 test system to be LEVELED with the reference
microphone ON.
8.9.2 Measuring the Overcoming of the Head-Baffle Effect
This section describes measuring how well the hearing aid overcomes the headbaffle
effect. The methods are different for CROS hearing aids than they are for
BICROS hearing aids.
8.9.2.1 CROS
GOOD
EAR
GOOD
EAR
PROBE MIC
BAD
EAR
12"
PROBE MIC
BAD
EAR
12"
SPEAKER
SPEAKER
unaided—Measurement of “good” ear
canal (baffled by head)
Set up the 8000 test system as follows.
GOOD
EAR
BAD
EAR
12"
• Reference microphone ON
SPEAKER
• Sound field LEVELED
• Unaided CUSTOM
PROBE MIC REFERENCE MIC
• Reference microphone over pinna of bad ear
• Probe microphone tube inside unoccluded ear canal of good ear
• Loudspeaker at 90º, 12 inches from bad ear