Frye FONIX 7000 - Manual (Page 166)

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FONIX 7000 Hearing Aid Analyzer
6.5.2 Choosing a speech weighting
By default, the Digital Speech (and Composite) signal uses the ANSI S3.42
speech weighting. Some clinicians, however, prefer to test using the ICRA
speech weighting, which was used in the development of some digital hearing
aids. The ICRA weighting available on the 7000 analyzer is based on the ICRA
CD track #1, “unmodulated moderate male weighted artificial speech,” devel-
oped by the International Collegium of Rehabilitative Audiologists (ICRA). See
Figure 6.5.2 for a comparison of an aid being tested with the ANSI and the ICRA
speech weightings.
To change the speech weighting:
1. Press [MENU] from a real-ear measurement screen.
2. Use [∨, ∧] to select Composite Filter under Source.
3. Use [<, >] to choose ANSI or ICRA.
4. Press [EXIT] to return to the real-ear measurement screen. Any Digital
Speech or Composite signal will use the new selected speech weighting.
Figure 6.5.2—A comparison of an aid being tested with Digital Speech using the ICRA (CRV 3)
and the ANSI S3.42 (CRV 2) speech weightings
6.5.3 Testing the digital filters
It is possible to add a bias tone to the Digital Speech signal in order to see how
the aid responds in the presence of noise at different frequencies. This is useful
for checking the filters of the hearing aid and determining how one channel of
the hearing aid reacts to noise in a different channel of the aid.
To introduce a bias signal in a measurement screen:
1. Enter the Real-ear Insertion Gain or Real-ear SPL screen, set up the patient
for real-ear measurements, and level the sound field speaker.