124 FONIX FP35 Hearing Aid Analyzer
Probe mic
Probe mic
3A
INSERT
EARPHONE
Foam eartip
Figure 5.3.6.2A—Insert probe microphone Figure 5.3.6.2B—Insert foam eartip
connected to insert microphone
5.3.6.3 Taking the RECD Measurement
If you’ve performed the steps described in Sections 5.3.6.1 and 5.3.6.2, you just
have to press [START/STOP] to take the RECD measurement. Results will be
displayed in graphical format in dB GAIN as well as numerical format in the
data table.
To erase the measured RECD, press [F4] and [START/STOP].
See Chapter 6 2CC-Targets for information on performing coupler measurements
to a target.
5.3.7 Measuring the Real-Ear to Dial Difference
The real-ear to dial difference (REDD) is the difference between an audiometer‘s
output in dB HL and the unaided response of the client in dB SPL.
To take the REDD measurement on the FP35 analyzer, you perform a probe
microphone measurement using an insert earphone or the sound field speaker
as the transducer of the test. In other words, when you perform an RECD mea-
surement (using an insert earphone), or an REUR measurement (using the sound
field speaker), you get the REDD for free.
• WhenSPEAKERisselectedintheASSESSMENTfieldinthemenu,the
REUR and REDD are obtained simultaneously by taking a sound field
unaided measurement.
• WhenINSEARisselectedintheASSESSMENTfield,theRECDand
REDD are obtained simultaneously by taking an unaided measurement
using an insert earphone.
