Speech Direction Detection

Bach Speech Direction Detection

How Our Ears Determine Speech DIRECTION

The secret of determining speech direction is binaural hearing and the location of the ears.

Because our ears are on opposite sides of our heads, the sounds heard by each ear vary in timingvolume, and frequency balance. These subtle differences are the clues that the brain uses to determine a sound’s emanating location.

Bach's Technology

As long as there have been hearing aids with directional microphones, a common assumption has been that hearing aid wearers look at the person to whom they are listening.

That theory is interesting, widespread, reasonable – and sometimes incorrect.

Bach Speech Direction Detection

Understanding speech in noisy environments is the biggest complaint for those with hearing loss.

In the real world, speech doesn’t always come from in front of the listener. We often have conversations with those to our side, even when the focus and our attention need to remain straight ahead. There can also be multiple people involved in a conversation and the target talker is not always positioned directly in front of the listener.

Bach utilizes Speech Target Pro to help hearing aid wearers experience the best perception of speech coming from different directions in noisy environments.

This premium-level technology uses the latest in algorithmic advances, including leveraging wireless technology to provide a variable directional beam based on the presence and location of a speech target.

Bach hearing aids overall strategy supports conversations with different types of background noise, rather than just a single class of “speech in noise”. Bach automatically engages the appropriate microphone and processing strategy in each hearing instrument when the classification is identified to be within a pre-engineered program.

17 wearers were asked to track various aspects of desired sounds and noises over a four-week period. Wearers reported on 1586 instances where speech was present. They disclosed that speech came from their front 1268 times and from other directions 318 times.

Thus, wearers reported that speech came from directions other than from the front approximately 20% of the time.

Why then are other hearing aid brands stuck on prioritizing sound emanating exclusively from the front of the wearer? The answer is their available technology; they had no other options.

Hearing aid technology wasn’t able to determine exactly the direction that the speech was coming from. That was until the introduction of Speech Target Pro and acoustic signal processing. Speech Target Pro is able to determine the speech direction on a moment-to-moment basis.

By analyzing the inputs from both microphones on each hearing aid and then the coordination of these incoming signals between the two devices collaboratively, it is possible to assess the speech direction of the desired signal with great accuracy.

There are important advantages to knowing speech direction and other speech signal variables relative to other surrounding background noises.
Bach points the target area of its directional microphones toward the speaker and away from other non-speech noise. Bach hearing aid technologies can also make other specific directional adjustments to enhance hearing aid performance.
Microphone location effect (MLE) for receiver-in-canal (RIC) hearing aids with microphones at the top of the pinna (outer ear) are different from the front, back, or sides.
Traditionally, the transfer function to account for MLE has always assumed a front-facing speaker because they had to pick a direction and it was the obvious choice.
Bach hearing aids can now determine the direction of speech and can alter the MLE to the best possible values for the orientation of the incoming speech signal, at the moment. This improves sound quality and the natural perception of direction.

Bach hearing aids know where speech is coming from thanks to a combination of binaural spatial processing and wireless communication. Bach uses speech detectors to identify when a dominant speaker is present from any angle, it then uses detectors to look at the signal-to-noise ratio (SNR) difference between the hearing instruments. 

Better Speech Understanding In Noise

Bach makes it possible for hearing aid wearers achieve better speech understanding in situations normally addressed by applying traditional directional microphones and/or noise-canceling algorithms.

Bach hearing aids are an incredibly advanced solution that is only possible by combining directional microphone technology with the latest wireless innovations. Coordination with other Bach signature features puts the focus on conversations for the best speech understanding, no matter what background noise is present.

For more information on Bach Hearing Aids, please email info@bachhearing.com, chat, or call 1-800-416-2434, Monday thru Friday, 9:00 a.m. to 9:00 p.m. Eastern Time (6:00 a.m. to 6:00 p.m. Pacific Time), USA.

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