How would you manage feedback with a traditional bone-anchored hearing solution?
The new OpenSound Optimizer that has been incorporated into the Ponto 5 Mini and eventually the rest of the Ponto 5 family defies conventional technology with a new unique and patented approach to feedback management. It's going to deliver more sound, not less. It does this by analyzing the amplified sound 56,000 times per second. It can detect and prevent audible feedback before it occurs. This means you no longer have to compromise on the dynamics of sound to reduce feedback and you can fit users with up to 6 dB of more stable gain.
First off with OpenSound Optimizer, the idea behind why we wanted to develop it was started with the knowledge that the most efficient way of removing feedback is by reducing gain. That presents a dilemma. As soon as feedback is detected, gain goes down. In the bigger picture, this isn't a good solution since we need that amplification to maintain audibility for our patients and speech understanding. From there, the idea came to turn off the amplification, but to do so really fast, very briefly, and only in the frequency bands where the feedback is detected. This allows us to be proactive instead of reactive. OpenSound Optimizer can detect and prevent feedback proactively even before it occurs.
First, we're going to use something that breaks the feedback path by introducing a breaker signal, and it's a patented breaker signal that we're using. What it does is pauses the amplification extremely briefly less than 16 milliseconds, and then reapplies it again very rapidly in a characteristic pattern. This is different than conventional technology, where on average they need 500 milliseconds to eliminate that audible feedback. Meaning that it takes them a long time to eliminate it, and then it continues to reduce the amplification until it realizes that the feedback is gone. We use this patented breaker signal that's very proactive and fast. It's going to detect and prevent the feedback in approximately 60 milliseconds. It's very precise. It really is only deployed in the effective frequency bands. It's very non-intrusive, so it's briefly applied, and it's very effective at stopping the feedback. The outcome is that there's no reduction in gain. In fact, we're able to get about 6 dB of additional gain. It has minimal impact on the entire speech spectrum, and the patients will not experience any audible feedback.
OpenSound Optimizer uses this patented technique, and it's called a spectral temporal modulation, to prevent feedback before it even occurs. In order to know if the sound is being re-amplified, OpenSound Optimizer is going to analyze the amplified sound by comparing the output signal to the input signal. It's going to estimate that loop gain. It works continuously performing rapid measurements in 28 independent frequency channels.
If the loop gain is positive, meaning sound is being re-amplified, hence feedback, more than its attenuated, OpenSound Optimizer is going to counter that, detect the acoustic changes, and immediately use that targeted breaker signal in one or more frequency bands, where it's present. When the feedback risk has passed, it automatically disengages the modulated breaker signal.
This Ask the Expert is an excerpt from Introducing the Ponto 5 Mini and RemoteCare for Oticon Medical.