Frye FP35 Manual

A SERVICE OF

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Real-Ear Measurements 163

NOTE: Although the above two measurements calls for the FP35 to be

UNLEVELED with the reference microphone OFF, the rest of the measurements

in this section call for the FP35 to be LEVELED with the reference microphone

ON.

5.9.2. 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.

5.9.2.1 CROS

Unaided—Measurement of “good” ear canal (baffled by head)

Set up the FP35 analyzer as follows.

•ReferencemicrophoneON

•SoundfieldLEVELED

•UnaidedCUSTOM

•Referencemicrophoneoverpinnaof

bad ear

•Probemicrophoneinsideunoccluded

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.

5.9.2.2 BI-CROS

Unaided—Measurement of “better” ear canal (baffled by head)

Set up the FP35 analyzer as follows.

•ReferencemicrophoneON

•SoundfieldLEVELED

•UnaidedsettoCUSTOM

•Referencemicrophoneoverpinna

of “bad” ear

•Probemicrophoneinsideearcanal

of better ear

REFERENCE MIC

PROBE MIC

12"

GOOD

EAR

BAD

EAR

SPEAKER

REFERENCE MIC

PROBE MIC

12"

BETTER

EAR

BAD

EAR

SPEAKER