DFS Ultra™ 

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 instrument 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 tones, beeps and musical notes. This failure often results in disturbing echoing or ringing artifacts.

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, in contrast, can amplify important everyday sounds like phones ringing, alarm beeps and music to desired levels without mistaking them for feedback.

DFS Ultra 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 instrument – unlike other systems that only model the feedback path.

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

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.

Together DFS Ultra and Whistle Control constitute an effective feedback suppression system with no compromise.

ReSound Alera® features the latest generation of Surround Sound by ReSound™ including DFS Ultra.

For more information, download Surround Sound by Resound  -Technical Background or the DFS Ultra white paper.