Feedback Canceller

Feedback Canceller prevents feedback in various environments by setting the desired adjustment control (Off, Static, or Adaptation) per program. Maximum Stable Gain (MSG) data including the Added Stable Gain (ASG) can be viewed per program for the hearing aid(s). The graph displays the range of stable gain in each channel and at what frequencies the gain may be limited. Added Stable Gain (ASG) measures the feedback canceller performance and reflects the additional gain available when the Feedback Canceller is initialized. The larger the number, the less chance there is for potential feedback.

 

Programs and Adjustment Control SettingsPrograms and Adjustment Control Settings

 

Feedback Canceller should be initialized before setting individual programs and viewing Maximum Stable Gain. Static cannot be selected until a successful initialization has occurred during the current fitting. The adjustment control setting automatically defaults based on the program selected. Music is automatically set to Subtle Adaptation, and Telecoil, Autocoil, Loop, and tinnitus stimulus only enabled programs are automatically set to Off and disabled unless the microphone is enabled. All other programs are automatically set based on the aid's recommended acoustic configuration. If earbud type 'Open' or 'Sleeve' or a 'Large' vent size is selected, the program is automatically set to Subtle Adaptation. The program is automatically set to Strong Adaptation for all other acoustic configurations.

 

Mid-frequency ManagementMid-frequency Management

 

If potential feedback is discovered in any program's mid frequencies during the initialization, Pro Fit will automatically enable the Mid-frequency Management feature to eliminate feedback in these channels. If this feature is enabled in a program and the adjustment control setting is changed to Off, or the microphone is turned off when previously on in a Telecoil, Autocoil, Loop, or tinnitus stimulus enabled program, this feature is automatically disabled. This feature can be enabled/disabled in any program except Disabled by clicking Settings.

  1. Connect and select the desired hearing aid(s) to adjust via Connect.
    Note:  The hearing aid(s) must be in the patient's ear(s) and the patient should remain quiet during the measurement.
  2. Click Connect.
  3. Click Feedback Canceller from the Left Navigation Menu.
  4. Enable or disable Optimize Acoustic Model if available.
    Note:  If On is selected and no REM Target Match data exists in the device, Feedback Canceller will automatically apply any recommended acoustic modeling changes if the initialization is successful. See Acoustics for more information. Feedback Canceller will not automatically apply recommended acoustic modeling changes if Off is selected. Click Information for more information.
  5. Click Begin Test to start the initialization measurement, and an animated icon appears, indicating the presence of a brief, complex sound in the patient's ear.
    Note:  This button is only enabled during a live or remote programming fitting. If a good static filter was obtained through the initialization, the initialization status Successful: Gain Margin Measured displays. If the initialization was unsuccessful, the status Completed: No Feedback Measured, and an alert Alert displays. Point to Alert and suggestions on obtaining a successful initialization display in a tooltip. If the initialization was successful and Optimize Acoustic Model was enabled, a message to match targets was displayed if Pro Fit applied any recommended acoustic modeling changes. A graph showing the 'Measured' response compared to the original 'Predicted' response is also displayed for select products. Click Target Match or Yes to match targets, or Do Not Target Match or No if target adjustments were made previously.
    Tip:  The Begin Test button changes to Cancel during the initialization process. Click Cancel to cancel the initialization during a live fitting only.

  6. Pro Fit automatically defaults to a binaural view if applicable. To adjust only the right or left hearing aid, click Select Right Only or Select Left Only.

    Note:  If fitting CROS/BiCROS devices, only the receiver aid can be adjusted; therefore, the side cannot be selected.
  7. Click on the specific program to view the adjustment control setting assigned.
    Note:  Custom programs created in the My Starkey mobile application can be adjusted during a live fitting. See Adjusting Custom Programs During a Live Fitting for more information.
  8. Select the desired adjustment control setting for the right hearing aid only, both hearing aids, or the left hearing aid only from the drop-down list.
    Note:  Static is recommended for patients who have specific lifestyle environments where an adaptive feedback cancellation system is not desired, such as healthcare workers and musicians who are exposed to high-frequency, repetitive sounds which may be interpreted as feedback. The Static setting would not attempt to cancel these sounds automatically. Static is unavailable if the program's directionality setting selected via Sound Manager is dynamic or adaptive. Click Information for more information regarding these adjustment control settings. This feature is unavailable for CROS/BiCROS products for programs assigned CROS mode. If the default adjustment control setting is changed and the feedback canceller is initialized again successfully, the setting will be reset to the default.
  9. If the program currently selected is dynamic or adaptive, click or to view the program's directional or omni Maximum Stable Gain data.
    Note:  Maximum Stable Gain data automatically displays if available. Maximum Stable Gain references 2cc Coupler Gain, which may differ from the graphical view currently selected. The graph displays a single value for the Peak Added Stable Gain (in dB), Maximum Stable Gain per channel, and bars representing the available gain margin per channel basis. The blue or red bars represent the amount of gain margin for each of the channels, and the gold bars (when present) represent the channel specific amount of gain with potential feedback.
    Note:  This feature is only available if the hearing aid connected supports a directional system. If there is feedback potential in any of the programs, an alert displays on the Left Navigation Bar and Alert to the right of Auto Adjust Apply button. Point to Alert and a list of programs with potential feedback displays in a tooltip.
  10. Click Apply to perform an automatic adjustment, and a pop-up window will appear if more than one program has potential feedback.
    Note:  The programs that have potential feedback are automatically checked. If only one program has potential feedback, the pop-up window does not display and the auto adjustment is automatically applied.
    Note:  If Apply Auto Adjust to eliminate feedback is checked via General Preferences, Pro Fit may automatically apply feedback-management processes following Feedback Canceller initialization. Depending on the hearing aid firmware and the detected feedback conditions, this may include mid-frequency management optimization, fast-compressor adjustments, and/or automatic gain reduction to Maximum Stable Gain. In addition, if a program is changed, these adjustments may be automatically applied if this preference is checked.
  11. Uncheck any programs to maintain the current settings and click Apply
    Tip:  To reverse any auto adjustments, see undo.