Digital Speech-in-Noise Tests

FONIX 6500-CX version 4.30 and above

The Digital Speech-in-Noise Test is designed to provide an accurate way to test digital hearing aids. These hearing aids respond differently to randomly interrupted signals than they do to continuous signals. The Digital Speech-in-Noise Test uses short bursts of real-time composite noise to test units that require a "speech-like" signal to produce accurate results. A bias signal can also be used to test the filtering devices on these aids.

Using the Digital Speech-in-Noise Test

1. Assuming the 6500-CX is on, leveled, and a hearing aid is set up to be tested, press [MENU] and then the [*] button to enter the Star Option.

 

2. Select DIGITAL SPEECH-IN-NOISE.

 

3. Press [START] to enter the Digital Speech-in-Noise screen. Then, to change settings, press [MENU].

 

4. Select between ICRA* and ANSI (the ICRA simulates long term average speech; the ANSI provides a higher signal-to-noise ratio) for the speech signal, PURETONE or NONE for the bias signal. Press [CONTINUE] to return to the test screen.

 

5. While running the test you can change the bias signal frequency (if you are using a bias signal) by pushing the left and right arrow buttons repeatedly. The up and down arrow buttons control the amplitude of the bias signal or the amplitude of the speech signal. Use the [START] button to change which signal you are controlling.

 

6. Exit the Star Option by pressing [CONTINUE].

* International Collegium of Rehabilitative Audiology

Testing Digital Hearing Aids (alternate method)
for FONIX 6500-CXs with software versions below 4.30

If you are using a 6500-CX that is not equipped with the Digital Speech-in-Noise Test or an FP40 that has the Composite Option, you can still determine if a digital aid is functioning properly, though not with the same accuracy.

First Alternative Method:

1. Put the 6500-CX in pure tone mode and turn the signal off.

 

2. Switch the 6500-CX to composite mode, and immediately press [FREEZE]. This procedure will measure the response of the hearing aid before the filtering device begins working.

 

3. To test the noise filter, press [FREEZE] again to start the signal. Leave the signal on. A hearing aid with a working noise filter will steadily reduce the gain over a period of five to ten seconds.

Second Alternative Method:

1. If your unit is equipped with the 0/60 option, you can use it to test whether or not a digital aid is functioning properly.

 

2. In the composite mode, push [0/60] once. This will turn off the signal.

 

3. Wait a couple of seconds, then press [0/60] again. Immediately press [FREEZE] to capture the response of the aid before the filtering device begins working.