FONIX® 8000 - Frye Electronics
FONIX® 8000 - Frye Electronics
FONIX® 8000 - Frye Electronics
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74 FONIX <strong>8000</strong> Hearing Aid Test System<br />
Analyzer Setup<br />
It is very important to pick a testing location that is free of magnetic disturbances,<br />
especially those caused by fluorescent lights and power lines. To do this:<br />
1. Locate a wide-range linear hearing aid with good low frequency response<br />
and a telecoil switch.<br />
2. Set the hearing aid to operate in the telecoil position and turn the gain control<br />
up to its full-on position.<br />
3. Connect the hearing aid to a coupler. Don’t insert the measurement microphone.<br />
4. Walk around your possible testing location and listen for raspy humming<br />
sounds from the hearing aid. This will be the aid responding to magnetic<br />
fields in the room.<br />
5. Pick a location that is as free of such sounds as possible. Rotate the aid in<br />
all directions when looking for a good site.<br />
Testing with the Sound Chamber Telecoil board<br />
Every 8120 Polar Plot Chamber and 8050 & 8060 Chambers has a built-in<br />
telecoil that can be used for telecoil testing.<br />
1. Set up the hearing aid for testing in the usual way by connecting it to the<br />
appropriate coupler and inserting the measurement microphone.<br />
2. Enter the Coupler screen by pressing [F1] in the Opening screen.<br />
3. Press [MENU] in the Coupler screen to open the local menu. Set the<br />
TRANSDUCER to TELECOIL under Source Settings and press [EXIT] to<br />
close the local menu.<br />
4. Use [F5] to set the Source Type to Composite.<br />
5. Press [START] to start a composite measurement.<br />
6. Look at the RMS OUT in the Curve Characteristics box. This shows the current<br />
output of the hearing aid to the magnetic field input.<br />
7. Position the hearing aid for maximum output. For BTE hearing aids, this<br />
usually occurs when the body of the aid is in a vertical position. If necessary,<br />
use Fun Tak to help hold the aid in that position. See Figure 3.4.10A.<br />
8. Use [, ] to change the intensity of the magnetic field. The choices are:<br />
OFF, 1.00, 1.78, 3.16, 5.62, 10.0, 17.8, 31.6, 56.2 and 100 mA/m. 31.6 is the<br />
default source intensity.<br />
9. Press [STOP] to stop the measurement or continue to test, as desired.
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