News & Reviews

Bernafon Zerena 9 Hearing Aid Review

Bernafon Logo

Independent review of the Bernafon Zerena 9 Hearing Aid

For the past couple of months, I have been trialling and evaluating the Bernafon Zerena 9 hearing aid.

You may not be familiar with Bernafon but they are the sister company to Oticon, one of the larger manufacturers of hearing aids.

I must admit, I really don’t like the name ‘Bernafon’. I have shied away from them for a number of years purely for that reason. Rumour has it their logo was drawn up in 1997 using word art and they haven’t bothered to change it since.

Word Art

Fortunately the lack of passion shown in the brand is not reflected in the quality of the product. I would much rather work with a company with a good product than good branding.

If you can look past the brand you will find a product that is better looking than it’s counterpart, the Oticon Opn. I think the slight ‘S’ bend gives it a real aesthetic edge over it’s competitors.

Bernafon Zerena Colour range

Bernafon Zerena 9 colour range

It shares the same internal architecture as the Oticon Opn and so we know the hardware works well. There is a premium look and feel about the Bernafon Zerena 9 and it uses an approach to amplification that is very unique.

Channel Free Processing

The unique selling point on offer by Bernafon is channel free processing.

It took me a day or so of reading about channel-free processing to really get my head around it. It contradicts everything that we think we know about how hearing aids work.

When I first heard of it, I thought it must be some marketing gimmick but it is actually an interesting approach for amplifying speech.

Before we look at channel free processing we first need to look at the traditional approach of all other manufacturers which is Multi Channel.

Multi-Channel Processing

As audiologists, we are taught that more channels on the hearing aid means greater quality in the sound. This is because it breaks down the same frequency range in to smaller segments.

For example, if we can adjust the volume using only one channel it is either up, or down much like your home television. If we have three channels, we can adjust bass, middle and treble. This is something you often see on home amplifiers or car stereos.

Hearing aids allow up to 20 channels to be adjusted much like a professional recording studio. It becomes very frequency specific and allows the audiologist to match your hearing loss with incredible accuracy.

Spectral Smearing

A hearing aid that uses multiple channels to detect and amplify speech needs to react to syllables rather than to individual phonemes. An example of one syllable is the word ‘car’, whereas the phonemes are the individual sounds ‘c’ ‘ar’.

If the multi-channel hearing aid were to react to phonemes instead of syllables we lose the characteristics of the word. This is because the phonemes are different frequencies and the channels would amplify them independently of each other. This results in all the phonemes being amplified to an identical intensity. This is called spectral smearing.

In reality we know that the consonant ‘c’ in the word ‘car’ doesn’t have as much energy as the vowel sound ‘ar’. The hearing aid needs to maintain the proportionate difference so it sounds natural to the listener.

Channel Free Processing

Bernafon uses a different approach to standard multi-channel processing. With ‘Channel Free’ the hearing aid is able to react much faster than multi-channel hearing aids without degradation of the quality. The Bernafon Zerena is able to process the phonemes rather than the slower syllables.

The Zerena still has all the programming ‘channels’ that an ordinary hearing aid has. We can program the Bernafon Zerena hearing aid just as accurately as any other device. The difference being is that once we click save, those channels lock together and become dependent of each other.

If you were to whistle next to the hearing aid, it would turn the overall volume up or down on all the channels until that pitch was audible and comfortable to the listener. The multi channel hearing aid would have processed this differently. The whistle would be filtered in to a channel and only that specific channel would react to the sound.

Multi-channel has always been the preferred route because processing speeds were not fast enough to react to phonemes.

Fast attack time

If you use the channel free approach and the attack time is too slow the sound quality would be inferior to multi-channel processing.

Fortunately, the processor inside the Bernafon Zerena hearing aid is extremely fast and samples speech much faster than multi-channel devices. This means the hearing aid can adjust the volume for each individual phoneme without affecting the quality of the sound to the listener.

If we go back to our previous example, the word ‘car’ can now be processed at a phoneme level without affecting the natural sound. This is because all the channels are fixed together to maintain the gain curve that was programmed for your hearing loss. This prevents the effect of spectral smearing. The theory is that this will be sharper and clearer than the multi-channel approach.

It is difficult to say whether that is true or not but my clients certainly felt there was a sharpness to the Bernafon Zerena. This was a direct comparison to other Hearables ‘Best Buy’ hearing aids.

Made for iPhone

The Bernafon Zerena hearing aid is made for iPhone. This means that it is able to connect directly to your iPhone using Bluetooth. It allows for streaming of music and telephone calls as well as remote adjustment of the volume and programs. The Bernafon app is identical to Oticon so I know this is intuitive from previous experience.

Bernafon Zerena iphone App


I really like Bernafon’s unique approach to  processing speech. It could be an alternative to try if you have a very dynamic user. They may get a sharpness of signal that may not be achievable from a multi-channel approach. As the architecture is the same as Oticon I am assuming that the technology is as reliable. Bernafon’s biggest weakness is in the brand itself, but look past this and you may be pleasantly surprised.

Need to contact a member of the team?

Get in touch