Head of Online Medical Content
Audiology Expert & Founder of Hearing Aid UK

Overview | The chip and speech technology | Size, weight and battery | Connectivity | Comparison table | Which one is right for me? | Conclusion | Key takeaways and FAQs
Latest Hearing Aid UK Update: 22/09/2026
Phonak currently offers two AI-driven ranges: EON, launched in September 2026, and Infinio Ultra, the platform it sits alongside rather than replaces.
Both use a dedicated chip to separate speech from background noise, but they differ in size, battery life and connectivity. Here's how they actually compare.
EON runs Phonak's new HYPERSONIC chip, powering Spheric Speech Clarity 3.0. Infinio Ultra Sphere runs the DEEPSONIC chip, powering the earlier Spheric Speech Clarity 2.0.
Both are built for the same job, separating speech from background noise in real time, from any direction. Phonak states EON's chip does this more efficiently, though the two deliver comparable speech-in-noise performance.
Phonak states EON is 25% smaller and 20% lighter than the previous Sphere generation, with a maximum of 38 hours of battery life, though Phonak's own datasheet suggests around 22 hours is more realistic in typical use, once streaming and time spent in noisy environments are factored in.
Infinio Ultra Sphere is larger but has the longer battery life of the two, up to 56 hours on a single charge, with an IP68 rating for dust and water resistance.
EON supports Auracast broadcast audio from launch, letting you connect directly to public sound systems in venues that support it. Infinio Ultra doesn't currently offer this. Both use AutoSense OS for automatic scene recognition, AI 8.0 on EON and 7.0 on Infinio Ultra.
Neither range has a telecoil. If you rely on induction hearing loops in a theatre, place of worship or community hall, that's worth knowing before choosing either.
Auracast is Phonak's alternative for venues that have installed the transmitters, but UK coverage is still limited, so it isn't yet a like-for-like replacement for a loop system.


| Phonak EON Sphere | Phonak Infinio Ultra Sphere | |
| Chip | HYPERSONIC | DEEPSONIC |
| Speech technology | Spheric Speech Clarity 3.0 | Spheric Speech Clarity 2.0 |
| Scene recognition | AutoSense OS AI 8.0 | AutoSense OS 7.0 |
| Size vs previous Sphere generation | 25% smaller, 20% lighter | |
| Telecoil | No | No |
| Battery life | Up to 38 hours (around 22 in typical use) | Up to 56 hours |
| Fitting styles | RIC only | RIC only |
If size, weight or Auracast compatibility matter to you day-to-day, EON is worth discussing with your audiologist. If longer battery life between charges matters more, or you're happy with the technology you already have, Infinio Ultra Sphere remains a strong, fully current option, not an outgoing one.
If you rely on a hearing loop, neither model has a telecoil, so that's worth raising with your audiologist regardless of which you're considering.
"These two sit closer together than the names suggest. EON is the newer, smaller device, but Infinio Ultra Sphere isn't a step down in what it can actually do for you.
It comes down to which trade-offs suit your day, not which one launched more recently."
says Paul Harrison, Audiology Expert & Founder, Hearing Aid UK
Because Phonak isn't claiming EON Sphere hears better in noise than Infinio Ultra Sphere, there's rarely an urgent case to switch on sound quality alone.
It's more often worth checking your current hearing aids are properly fitted and fine-tuned before considering an upgrade, since that generally makes a bigger difference than the platform itself.
EON and Infinio Ultra Sphere both use a dedicated AI chip to separate speech from noise, but EON is smaller, lighter and adds Auracast, while Infinio Ultra Sphere offers longer battery life and remains fully current. Which suits you depends on your day-to-day priorities rather than which one is newer.
If you'd like to compare both in person, call us free on 0800 567 7621, or book a free hearing test and one of our audiologists can talk you through the differences honestly.
Is Phonak Infinio Ultra being discontinued now that EON has launched? No. Infinio Ultra Sphere and Infinio Ultra R remain current Phonak ranges, fully available and supported through Hearing Aid UK's audiologist network.
Does EON sound better than Infinio Ultra Sphere? Phonak doesn't claim this. Both use a dedicated chip built for the same job, separating speech from background noise, just on different hardware generations.
Which has the longer battery life, EON or Infinio Ultra Sphere? Infinio Ultra Sphere, at up to 56 hours compared with EON's up to 38 hours, though real-world use depends on streaming and which features are active on both.
Can I compare EON and Infinio Ultra Sphere in person before choosing? Yes. You can book a free appointment with one of our audiologists to hear both and talk through which suits your listening environments.
Do I need to upgrade if I already wear Infinio Ultra Sphere? Not necessarily. Since EON isn't claimed to outperform Infinio Ultra Sphere for speech in noise, it's often more useful to check that your current hearing aids are properly fitted before considering a change.
We'll say this again because it matters: even the most advanced Phonak technology won't deliver proper results if it's not fitted and programmed correctly for your specific hearing loss and preferences.
The difference between a well-fitted Infinio Ultra and a poorly fitted EON is far greater than the technology gap between the two models.
We'll take the time to understand not just your hearing loss but your lifestyle, the environments that challenge you, and what you actually need from your hearing aids before recommending either.
Call us free on 0800 567 7621 or book a free hearing test, and one of our HCPC-registered audiologists can talk you through the differences honestly.
Phonak EON Sphere vs Phonak Infinio Ultra Sphere
Phonak Infinio Ultra Sphere i90 vs Unitron Smile Moxi RX 9
Rugged Hearing Aids Do not spend hundreds of pounds without getting a second opinion from us.
Not only are the prices great, but the service is fantastic! Many thanks to your team.In general, any audiologist will always recommend to you the hearing aid model that best suits your needs. Here is a useful checklist to make sure that is the case.
If you have significant hearing loss in both ears, you should be wearing two hearing aids. Here are the audiological reasons why:
Localisation: The brain decodes information from both ears and compares and contrasts them. By analysing the minuscule time delays as well as the difference in the loudness of each sound reaching the ears, the person is able to accurately locate a sound source.
Simply put, if you have better hearing on one side than the other, you can't accurately tell what direction sounds are coming from.
Less amplification is required: A phenomenon known as “binaural summation” means that the hearing aids can be set at a lower and more natural volume setting than if you wore only one hearing aid.
Head shadow effect: High frequencies, the part of your hearing that gives clarity and meaning to speech sounds, cannot bend around your head. Only low frequencies can. Therefore, if someone is talking on your unaided side, you are likely to hear that they are speaking, but be unable to tell what they have said.
Noise reduction: The brain has its own built-in noise reduction, which is only really effective when it is receiving information from both ears. If only one ear is aided, even with the best hearing aid in the world, it will be difficult for you to hear in background noise as your brain is trying to retain all of the sounds (including background noise) rather than filtering them out.
Sound quality: We are designed to hear in stereo. Only hearing from one side sounds a lot less natural to us.
Fancy some further reading on this topic? You can read about why two hearing aids are better than one in our article, hearing aids for Both Ears, here
For most people, the main benefit of a rechargeable hearing aid is simple convenience. We are used to plugging in our phones and other devices overnight for them to charge up. Here are some other pros and cons:
For anybody with poor dexterity or issues with their fingers, having a rechargeable aid makes a huge difference, as normal hearing aid batteries are quite small and some people find them fiddly to change.
One downside is that if you forget to charge your hearing aid, then it is a problem that can't be instantly fixed. For most, a 30-minute charge will get you at least two or three hours of hearing, but if you are the type of person who is likely to forget to plug them in regularly, then you're probably better off with standard batteries.
Rechargeable aids are also a little bit bigger and are only available in Behind-the-Ear models.
Finally, just like with a mobile phone, the amount of charge you get on day one is not going to be the same as you get a few years down the line. Be sure to ask what the policy is with the manufacturer's warranty when it comes to replacing the battery.
For most people, the answer is yes. But it's never that simple.
The majority of hearing problems affect the high frequencies a lot more than the low ones. Therefore, open fitting hearing aids sound a lot more natural and ones that block your ears up can make your own voice sound like you are talking with your head in a bucket. Therefore, in-ear aids tend to be less natural.
However, the true answer is we can't tell until we have had a look in your ears to assess the size of your ear canal, and until we have tested your hearing to see which frequencies are being affected.
People with wider ear canals tend to have more flexibility, also there are open fitting modular CIC hearing aids now that do not block your ears.
There is also the age-old rule to consider, that a hearing aid will not help you if it's sat in the drawer gathering dust. If the only hearing aid you would be happy wearing is one that people can't see, then that's what you should get.
Most people can adapt to any type of hearing aid, as long as they know what to expect. Have an honest conversation with your audiologist as to what your needs are.
Generally speaking, six or more. Unless it's none at all. The number of channels a hearing aid has is often a simplistic way an audiologist will use to explain why one hearing aid is better than another, but channels are complex, and it is really not that straightforward. Here are some reasons why:
Hearing aids amplify sounds of different frequencies by different amounts. Most people have lost more high frequencies than low, and therefore need more amplification in the high frequencies. The range of sounds you hear is split into frequency bands or channels, and the hearing aids are set to provide the right amount of hearing at each frequency level.
Less than six channels, and this cannot be done with much accuracy, so six is the magic number. However, a six-channel aid is typically very basic with few other features and is suitable only for hearing a single speaker in a quiet room. The number of channels is not what you should be looking at; it's more the rest of the technology that comes with them.
As a final note, different manufacturers have different approaches. One method is not necessarily better than any other. For example, some manufacturers have as many as 64 channels in their top aids. Most tend to have between 17 and 20. One manufacturer has no channels at all.
Manufacturer's warranties typically last between 2-5 years, depending on the brand and model, and cover defects in materials and workmanship. This includes repairs for component failures, electronic malfunctions, and manufacturing defects, but excludes damage from misuse, accidents, or normal wear. Most manufacturers also include loss and damage insurance for the first year.
We handle all warranty claims on your behalf, liaising with manufacturers and ensuring you get replacement devices quickly when needed. This comprehensive warranty coverage, combined with our lifetime aftercare, gives you complete peace of mind. Find out more about our warranty cover here
Our hearing tests are completely free, whether at our clinics or in your home. Unlike other providers who charge £30-£100 for home visits, we believe hearing healthcare should be accessible without financial barriers. Our comprehensive assessments include examination by an HCPC-registered audiologist, audiogram results, and personalised recommendations.
All testing, future adjustments, and ongoing support are included at no extra cost. While NHS tests are also free, typical 6-week waiting periods often lead people to seek immediate private testing. We provide prompt, professional assessments that fit your schedule and budget.
Yes, we offer completely free home visits throughout the UK, and this service is included in our prices with no additional charges. Home visits are particularly valuable for people with mobility issues, busy schedules, or those who simply prefer the comfort and convenience of their own environment.
Our audiologists can conduct full hearing tests, fit hearing aids, and provide ongoing support in your home. This service sets us apart from many providers who either don't offer home visits or charge extra for them.
We can offer prices up to 40% lower than high street retailers because of our business model. As a network of 200+ independent audiologists, we don't have the massive overheads of large retail chains - no expensive high street premises, no sales targets pushing audiologists to sell the most expensive options, and no costly marketing campaigns.
However, we maintain the same buying power as the big chains because we purchase on behalf of our entire nationwide network. This means you get access to the same premium hearing aids with professional service, but at genuinely competitive prices.
We offer a comprehensive 60-day money-back guarantee, which gives you twice the industry standard time to properly assess whether your hearing aids are right for you. This extended period recognises that adjusting to hearing aids takes time, and your brain needs several weeks to adapt to the amplified sounds.
Unlike many providers who offer just 30 days, we believe 60 days gives you the confidence to test your hearing aids in all the situations that matter to you - from quiet conversations at home to busy restaurants and outdoor activities.
When we refer to a product as 'Latest Launch', we mean it is the latest to be released on the market.
When we refer to a product as 'New', we mean that the product is the newest hearing aid model on the market.
When we refer to a product as 'Superseded', we mean that there is a newer range available which replaces and improves on this product.
When we refer to a product as an 'Older Model', we mean that it is has been superseded by at least two more recent hearing aid ranges.