Frye FONIX 7000 - Measuring the Overcoming of the Head-Baffle Effect; Cros

Real-Ear Measurements 169
6.9.2 Measuring the Overcoming of the Head-Baffle Effect
This section describes how to measure how well the hearing aid overcomes the
head-baffle effect. The methods are different for CROS hearing aids than they
are for BICROS hearing aids.
6.9.2.1 CROS
Unaided—Measurement of “good” ear canal (baffled by head)
Set up the 7000 test system as follows.
• Reference microphone ON
• Sound field LEVELED
• Unaided CUSTOM
• Reference microphone over pinna
of bad ear
• Probe microphone inside unoc-
cluded ear canal of good ear
• Loudspeaker at 90º, 12 inches
from bad ear
Aided—Measurement of “good” ear canal (baffle overcome by aid)
Same setup as above, except:
• Aid in place in good ear and set to normal user gain.
The difference curve, labeled “Insertion Gain” on the screen, shows the benefit
the aid gives for sound arriving from the “bad” side.
REFERENCE MIC
PROBE MIC
12"
GOOD
EAR
BAD
EAR
SPEAKER
REFERENCE MIC
PROBE MIC
12"
GOOD
EAR
BAD
EAR
SPEAKER