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FONIX FP35 Quick Reference Guide
3.1.3 Testing Digital Hearing Aids
The ANSI S3.22-1996 “labeling” standard for hearing aids was not designed
with digital hearing aids in mind. In fact, most of the testing methods employed
by ANSI 96 have been around since the 1970s. However, since ANSI is a stan-
dard, in order to conform to that standard, it must use only the testing tech-
niques outlined in the standard. For this reason,
the FP35 has no provisions for
incorporating composite or digital speech into the ANSI 96 standard.
In order to test digital hearing aids with “noise reduction” or “speech enhance-
ment” features to the ANSI 96 standard, put the aid in “test” mode via its pro-
gramming software and do the steps outlined in Section 3.1.2.
In order to get an accurate picture of the aid’s actual performance when it goes
home with your client, put the aid in the mode you will use for that client, and
perform response curve measurements in the coupler and in the real-ear via the
procedures described in Chapter 2 and Chapter 4 using the digital speech (DIG
SPCH) signal source.
3.2 IEC Testing
The IEC 118-7 standard was designed by the International Electrotechnical
Commission to assess hearing aids. The performance part of that standard can
be included as an automated sequence on your FP35.
The [F4] or [F5] key in the Opening screen is normally used for entering the
IEC screen. Press whichever key is labeled as “IEC.”
3.2.1 Setting Up the Hearing Aid for Testing
1. Set the controls on the aid (except for compression controls) to give the
maximum output and gain.
2. Set the aid for the widest frequency response range.
3. Set AGC aids for maximum compression.
4. Make sure that the gain control of the aid is full on.
5. Set the aid up in the sound chamber as usual.
6. Press [F1] to select aid type.
7. Press [F2] to select between a full-on gain measurement at 50 dB or at 60
dB.
8. Press [F3] to select a reference frequency of 1600 Hz or 2500 Hz. Select 2500
Hz for high frequency emphasis aids.
9. Press [F4] to choose whether to test an I/O curve during the test sequence.