FONIX® 8000 - Frye Electronics

Real-Ear Measurements 165
8.3.7 Entering an REDD transform
The REDD transform affects how dB HL values are converted to dB SPL.
to enter a measured reDD value:
1. Enter the Real-Ear Navigation screen by pressing [F2] from the Opening
screen or [EXIT] from a real-ear screen (such as the Audiogram Entry
screen).
2. Press [F2] to enter the Real-Ear Target screen.
3. Press [MENU] in the Real-Ear Target screen.
4. Select REDD using [, ].
5. Choose CUSTOM using [, ].
6. Press [EXIT] to return to the Real-Ear Target screen.
7. Use [F1] to select the desired ear.
8. Use [F2] to select REDD. The REDD column for the selected ear will now be
highlighted.
9. Use the arrow keys to input the REDD transform. The [, ] keys select the
frequency. The [, ] keys select the amplitude.
8.4 Real-Ear Measurements
The 8000 Hearing Aid Test System has three real-ear measurement test screens:
Insertion Gain, Real-ear SPL, and Visible Speech. The Insertion Gain and Realear
SPL screens are explained in this section. See Section 8.7 for operation of
the Visible Speech screen.
8.4.1 Measuring in the Insertion Gain screen
Insertion Gain is the most conventional method used for performing real-ear
measurements. In the typical insertion gain procedure:
1. The probe tube is inserted into the ear canal. (Section 8.2.3)
2. The sound field speaker is leveled. (Section 8.2.4)
3. The unaided response is measured. (Section 8.4.3)
4. The hearing aid is carefully inserted into the ear.
5. The aided response is measured. (Section 8.4.4)
6. The insertion gain response is compared to the prescribed insertion gain target
and any necessary adjustments are made to the hearing aid in order for
the response to better match the target.
The Insertion Gain screen itself consists of two graphs. (See Figure 8.4.1.) The
bottom graph displays an unaided response and up to four aided responses in
dB Gain or dB SPL. The top graph displays a prescribed insertion gain target
and up to four insertion gain curves. Insertion gain is the difference between the
patient’s aided and the unaided responses.