Head of Online Medical Content
Audiology Expert at Hearing Aid UK

Overview | What's actually inside | Comparison chart | Where Phonak is better | Which one is right for you? | Key takeaways
Latest Hearing Aid UK Update: 08/07/2026
Buying a premium hearing aid can feel like a big decision, especially when you're not sure whether you're getting the best price for what you actually need. If you've recently been quoted for a Phonak Audeo Infinio Ultra Sphere i90, it's worth knowing that Phonak's parent company, Sonova, also owns Unitron.
Unitron's Smile Moxi RX 9 (launched in June 2026) uses the same AI chip as the Phonak Audeo Infinio Ultra Sphere i90, and it's significantly less expensive.
The two aids aren't identical, but for many people they do a very similar job. We know brand names and model numbers can feel like a maze when you're trying to make a sensible decision, so this article compares these two specific models directly, based on our own HCPC-registered audiologists' hands-on experience fitting both brands.
In plain terms, both of these aids have an extra chip built purely to help you follow speech in noisy places, like restaurants or family gatherings: one for everyday processing (Bluetooth, streaming, automatic switching between listening environments) and a second, dedicated AI chip called DEEPSONIC.
Sonova launched the Phonak Audeo Sphere Infinio in August 2024; this was its first hearing aid with this kind of dedicated chip. The range also got an upgraded version called the Phonak Audeo Ultra Sphere Infinio in October 2025. Sonova launched the Unitron Smile Moxi RX 9 in June 2026; this is their most recent hearing aid using the DEEPSONIC AI chip.
The hardware in all of these aids is the same, but the software and appearance of the aids are a little different, so they won't look and sound completely identical, just very similar.
The brands describe the features using different terms for the same process; Phonak markets the noise reduction feature as "Spheric Speech Clarity," whereas Unitron's name for the feature is "SoundSonic360."
The trickiest bit tends to be the confusing model names. For Phonak, if you want these features, make sure the model name has the word "Sphere" in it; for Unitron, the model must have "RX" in it. The ones without do not have the DEEPSONIC AI chips.
"People often assume the more expensive aid must be the better one, and sometimes that can be true, but not here. These two share the same core technology. What actually matters is a proper assessment of your hearing and your day-to-day listening situations, not the price tag."
Paul Harrison, Audiology Expert & Founder, Hearing Aid UK


| Feature | Phonak Infinio Ultra Sphere i90 | Unitron Smile Moxi RX 9 |
| Style | RIC (Receiver-in-Canal, worn behind the ear with a small wire to the ear canal) | RIC (Receiver-in-Canal, worn behind the ear with a small wire to the ear canal) |
| Technology level | Premium | Premium (only the RX models have this chip) |
| Speech-in-noise chip | Spheric Speech Clarity | SoundSonic360 |
| Rechargeable | Yes | Yes |
| Bluetooth | Yes, up to 8 paired devices | Yes, up to 8 paired devices |
| RogerDirect | Yes | Yes |
| Roger microphone blending | Yes, blends Roger mic audio with nearby voices | As far as we know, but worth double-checking with your audiologist |
| Colour options | 7 | 6 |
As far as we can tell, this specific setting isn't currently available on the Unitron. Beyond that one setting, if Roger matters to you (practically speaking, for most people it doesn't), it's worth asking your audiologist to confirm.
If you've been quoted for the Phonak i90 purely because you were shown it first, it's worth asking your audiologist to price the Unitron Smile Moxi RX 9 alongside it. If Roger microphones, or the longest available track record, matter most to you, the Phonak is likely still the better fit, and that's a perfectly good reason to choose it.
If you mainly care about strong speech-in-noise performance at a lower price, the Unitron deserves serious consideration. Either way, you're not expected to make this decision alone. The final recommendation should come from a qualified audiologist who has actually assessed your hearing and your day-to-day listening situations, not from a brand name alone.
This isn't unusual. Sonova runs Phonak as its premium flagship brand and Unitron as its value-focused sibling, sharing engineering across both to keep research and manufacturing costs down. If two aids are doing essentially the same job, the price difference is simply worth knowing about before you commit to either.
Hearing Aid UK doesn't manufacture hearing aids, has no affiliation to any brand, and therefore has no reason to steer you towards either brand.
Around 18 million adults in the UK live with hearing loss, according to RNID, and most will encounter this exact "which one do I choose" moment at some point. Our job is simply to lay out what we found, honestly, so you can make a decision that feels right for you, with proper support from someone qualified to give it.
There's no single "better" hearing aid here, only a better fit for how you actually live and listen, and an honest comparison from our experts. If you'd rather get similar speech-in-noise performance without paying for the flagship name, the Unitron is a genuinely credible choice.
Either way, the decision doesn't rest on brand names or spec sheets, but a professional hearing assessment from someone qualified to help you find the right fit.
Book a free hearing test with one of our HCPC-registered audiologists, in a local clinic or in your own home, and get honest, impartial advice on which of these two aids (if either) is right for you. Call 0800 567 7621 or book your free hearing test today.
We'll say this again because it matters: even the most sophisticated hearing aid 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 Ultra and a poorly-fitted Sphere 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.
Phonak Infinio Ultra Sphere i90 vs Unitron Smile Moxi RX 9
Rugged Hearing Aids
How long do hearing aids last? 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.