What are CROS B Hearing Aids?
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What are CROS B Hearing Aids?

Published On: July 15, 2019

What are CROS B Hearing Aids?

A person with single-sided hearing loss has lots of challenges when it comes to perceiving sounds from his or her environment. One of them is the inability to perceive sound on the sound of the non-hearing ear.

To compensate for this, a person with only one hearing ear will need to adjust his or her head to receive the sound more clearly.

Another problem with single-sided hearing loss is that he or she cannot make up for the direction of the source of the sound. Both ears work together to create a 360-field. A person with both ears working can, thus, locate the source of the sound. A person with a one-sided hearing takes the information from one side of the ear only making it impossible to approximate the location of the source of the sound.

What is CROS technology?

CROS technology for hearing aids stands for Contralateral Routing of Signal. CROS has two main functions:

  1. It allows picking up the sound on the side of the non-hearing ear and transmits the information wirelessly to the hearing aid on the hearing ear.
  2. The hearing aid on the good ear will play the sound that the device on the non-hearing ear has picked up.

CROS allows one to get complete audio information of the environment even with one non-hearing ear. With this technology, a person’s ability to hear, regardless of where the source of the information comes from, is dramatically improved.

CROS system consists of two individual devices—one with a single microphone and another with a receiver. The non-hearing ear is fitted with the device that has the microphone while the hearing ear is fitted with the device that contains the receiver.

The device on the non-hearing ear picks up sound information and transmit them to the device on the hearing ear through a built-in wireless technology.

This way, the normal ear would be able to pick up sounds from the side of the non-hearing ear improving the hearing of the patient.

A similar but different technology to CROS is the BiCROS system. In this system, the non-hearing ear is fitted with a device that has a microphone in it while the other ear is fitted with conventional hearing aid.

BiCROS works for those which both ears having hearing problems but can still hear to some degree. In BiCROS, the device with microphone is fitted to the ear with poor hearing and the conventional hearing aid, which also receives information from the device on the other ear similar to CROS, is fitted to the better ear.

Who Would Benefit from a CROS System?

CROS is ideal to patients with one hearing ear and one non-hearing ear. The non-hearing ear must not be able to benefit from any amplification and that it mustn’t be able to hear anything at all.

In this condition, the side of the non-hearing ear would not be able to receive any sound information from the environment. CROS works by allowing a patient to pick up sound information from such a side and hear them through the hearing ear.

On the other hand, the BiCROS system only works for those with some form of hearing loss to both ears but both can still pick up the sound to some degree.

Benefits of CROS System

#1 Clearer hearing and improved conversation

People with unilateral hearing loss find it difficult to converse in difficult listening situations like in the public or in a restaurant. This is made worse if the source of the sound is on the side of the non-hearing ear. With CROS technology, patients can experience clearer and easier conversation. The precision of audibility and the accuracy of detecting speech is also improved.

#2 Improved understanding of speech in noise

The unilateral hearing loss makes it difficult for patients to comprehend sounds in a noisy environment. With CROS technology, sounds from objects nearer to the ear are enhanced making it easier for the patient to decode the information he or she hears even in noisy and challenging environments.

#3 Wireless Functionality

CROS technology makes it easier to manage two individual devices because of wireless connectivity. Wireless functionality allows control over the devices without the use of cords or wires. In addition, the sound is transmitted from one device to another without the need to connect them in a way. The process is instantaneous and automatic.

Phonak CROS B Hearing Aid

Currently, one of the big names when it comes to CROS B hearing devices is Phonak. The company has done a lot of progress in providing solutions to people with single-sided hearing loss. Over the years, Phonak has done many changes to their product to improve the user experience.

One of them is compatibility. Phonak CROS B Hearing Aids are compatible with other devices and can be used alongside them. For instance, say you’re already using a different device as a hearing aid, if you want a CROS device from Phonak, chances are, it is compatible with it and can be used alongside.

Phonak CROS B hearing aids boast of the following features:

#1 Easy fitting

The device is operating during the fitting process thus the patient can give his or her feedback during the fitting process. This makes the fitting process precise, easy and fast. The patient is assured of a great sound quality after the fitting process.

#2 Zooms in on a single voice

Phonak CROS B can lock in and zoom in on one voice improving speech intelligibility by up to 60% in challenging and noisy environments. The feature StereoZoom is also available in two levels which the patient can select from for ease of use and improved the user experience.

#3 Automatic Stereo Zoom

The ability of the device to lock in and zoom in on an object is automatic. That is, the patient needs not tweak or toggle buttons in order to improve his or her hearing in the difficult environment. In addition, the device can easily detect the environment type and adjust its settings accordingly.

#4 Rear ear sound

The device can mimic and simulate real-life sound. This provides a natural-feel experience to patients as one can experience natural sound perception. Thanks to a technology that allows the device to adjust the volume and location of the sound.

#5 Rechargeable device

A charge typically lasts for 10-12 days. Afterward, one needs simply to charge the device to enjoy another 10-12 days of operation. This is unlike conventional hearing aids where most of them require a battery. Not only are the batteries expensive, one needs to replace them every now and then to keep the device operational. Phonak devices don’t need you to take the battery out or replace them. By making their device rechargeable, they have effectively provided a solution to this problem that most patients encounter.

How effective is Phonak CROS B Hearing Aid?

To test how effective their products are, Phonak conducts regular research on CROS B products’ effectiveness. What the company boasts about is their binaural adaptive beamformer that improves the experience of the listener in a noisy environment.

In a 2013 study involving 20 patients, Phonak investigated on the effectiveness of their device in terms of improving speech intelligibility using their latest beamformer technology.

The study concluded with a definitive finding that the binaural adaptive beamformer feature of their CROS II (an improved CROS) works.

Models available

For Phonak CROS B hearing aids, there are two popular models to choose from depending on the level of your hearing loss, personal preferences, and hand dexterity.

CROS B-312

This model is small and can be unnoticeable once worn on the ear. Because of its size, its battery life can only last from 10-12 days before you will need to recharge.


CROS B-13 is a larger model of the two. Unlike the B-312, B-13 is noticeable when worn. Its large size makes it ideal for people with handling difficulty and poor eyesight. It also has dedicated volume control buttons that allow one to adjust the volume for ease of use. Because of its size, its battery can last longer—typically, from 18-21 days, before you will need to recharge.


Single-sided deafness (SSD) has its own set of challenges that cannot be addressed by conventional hearing aids. For SSD, the only available solution is Contralateral Routing of Signal.

In SSD, a patient cannot completely gather sound information from the side of the non-hearing ear. Thus, a person needs to constantly adjust his or her head or position well so that he or she can use the hearing ear.

Some instances, however, do not allow one to turn the head or position. This is where benefits from a CROS hearing aid comes in.

CROS hearing aid allows a person to hear from the side of the non-hearing ear through a device that collects sound information. The information is then wirelessly transferred to the hearing ear.

Advanced devices such that of Phonak can even simulate sound location making the hearing experience of people with SSD close to that of a normal person.


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