DFS Ultra™ II


DFS Ultra II

  • Suppresses feedback, while allowing sufficient gain
  • No introduction of artifacts or compromised sound quality
  • Music Mode setting ensures a clear, rich, distortion-free music experience

    The feedback challenge

    Most feedback suppression systems have limited ability to operate effectively in dynamic real-world situations.

    Factors such as room reverberation and nonlinearities of the hearing aid can cause the very whistling and chirping the system is supposed to eliminate.

    In addition, most systems cannot distinguish between real feedback and certain external tonal sounds such as tones, beeps and musical notes. This failure often results in disturbing echoing or ringing artifacts.

    No compromises

    As a result, most feedback suppression systems compromise. They must “choose” between providing sufficient gain, sound quality or feedback suppression in critical situations.

    For example, getting sufficient amplification might mean tolerating poor sound quality caused by the system erroneously attacking non-feedback sound inputs.

    Yet DFS Ultra II, in contrast, can amplify important everyday sounds like phones ringing, alarm beeps and music to desired levels without mistaking them for feedback – thanks to the most refined sound input analysis and our unique two-filter feedback cancellation system.

    Unlike other feedback systems, which use calibration for limiting gain only, DFS Ultra II uses the calibration procedure to set a static filter. Better precision and scaling optimizes the system’s performance and allows the adaptive filter to cancel feedback more accurately than was previously possible.

    DFS Ultra Figure_13

    DFS Ultra II analyzes and models the incoming sound and uses this information to prevent the feedback cancellation filters from attacking desired sounds. This results in excellent feedback cancellation performance without creating disturbing sound quality artifacts.

    Undistorted sound

    DFS Ultra II also uses input signal modeling, a major breakthrough in feedback cancellation processing.

    This unique technology enables our system to maintain a representation of the sound entering the hearing aid – unlike other systems that only model the feedback path.

    The advantage is that DFS Ultra II accurately distinguishes between feedback and non-feedback sounds, which vastly improves its dynamic behavior.

    Advanced setting for music

    Music is a perfect example of how DFS Ultra II’s accuracy can make a difference.

    Music is different from speech and other sounds in that it comprises a greater dynamic range and often contains tonal qualities that can be easily mistaken for feedback. Traditional feedback control systems may erroneously attempt to cancel these tones, resulting in sound artifacts that are detrimental to the overall sound quality.

    The Music Mode feature in DFS Ultra II controls feedback while maintaining a more accurate representation of music. It provides excellent sound quality without tonal artifacts for hearing aid users who enjoy or play music, giving users a clearer, richer distortion-free music experience.

    Whistle Control

    Whistle Control is usually needed when there are large, sudden changes in the feedback path, like when a phone is placed near the hearing aid. It breaks the amplification loop that can otherwise result in whistling and squealing.

    DFS Ultra II with integrated Whistle Control is an advanced feedback suppression system with no compromise. Allowing users to enjoy extra comfort and better audibility – even in the most challenging situations such as listening to music and using the phone.

    DFS Ultra Figure_14 

    ReSound Verso  features the latest generation of Surround Sound by ReSound, including DFS Ultra II. For more information, download Surround Sound by Resound – Technical Background or the DFS Ultra II and Music Mode whitepaper.