Improving sound quality and localization

April 14, 2016 by Marco Di Manno


Restoring proper sound localization and sound directivity is an important feature for today’s growing population of behind-the-ear (BTE) hearing aids users. As such, True Directionality™ microphone processing is used to address these specific needs.

First, let’s take the example of a person wearing no hearing aids at all, and of a person fitted with in-the-ear (ITE) hearing aids in both ears. In both cases, sound localization occurs normally from the front, back, and sides, due to the way that sound waves travel around the body, head, and outer ear. Specifically, frequencies greater than 1,000 Hz are collected from the front by the pinna, whereas lower frequencies bend and travel around the head and torso, entering the ear canal directly with no influence from the pinna.

Now, let’s take the example of a person fitted with behind-the-ear hearing aids in both ears. Because the microphones of BTE hearing aids sit higher on the ear—compared to microphone placement on a completely-in-canal (CIC) style, for example—some of the natural characteristics of our inherent spatial localization abilities are lost, making it difficult at times for BTE users to know if sound is coming from the front or back.

True Directionality™ in BTE is a feature designed to eliminate this source of confusion by imitating the way the pinna picks up sound in the unaided ear, thereby preserving the manner in which low and high frequency sounds are initially collected and sent through the auditory system by head shadow effects and the shape of the external ear. The True Directionality™ microphone option adapts to each listening environment and offers the most effective signal-to-noise ratio in both quiet and noisy environments.

Consult an audioprosthetist to learn more.

To determine which hearing aids are best for you, consult an audioprosthetist.

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