If you’re comparing the photos of the Audeo Infinio Ultra Sphere—Phonak’s most powerful hearing aid to date—to the product’s name, you’re not crazy: It’s not the slightest bit round. Rather, it’s a traditional, teardrop-shaped, behind-the-ear hearing aid that takes its name from Phonak’s new Spheric Speech Clarity 2.0 system, designed to enhance the understandability of conversations in noisy conditions, no matter what direction the voices are coming from.

Yes, Phonak Audeo Infinio Ultra Sphere is indeed a mouthful. For this review, I’ll call it the Ultra Sphere. The other new hearing aid system in the Infinio Ultra line, called the R, is available as a less advanced, cheaper model.

The big sell with the Sphere is that it includes not one processing chip but two. The new DeepSonic DNN (deep neural network) chip is responsible for multidirectional speech processing in noise. That’s included on top of Phonak’s older Era chip, which launched in 2024 and handles core audio processing and wireless functions. Are two chips better than one for hearing clearly? I wore the Ultra Sphere hearing aids for a week to find out.

An Oversize Profile

The Ultra Sphere hearing aids are visibly larger than most modern behind-the-ear (BTE) aids, clearly due to the extra silicon inside. At 3.39 grams each, that’s a significant size increase over devices like the 2.58-gram Jabra Enhance Select 700 or the 2.68-gram Horizon Go 7IX. But while they’re more readily visible to outside observers, that differential doesn’t noticeably impact comfort, even with long-term wear. (More on this later.)

Both hearing aids have a two-way rocker button used for power, volume, and media control. Tap control is also an option for certain Bluetooth functions, but this is disabled in the MyPhonak app by default. The units carry an IP68 weatherproof rating and are available in seven colors. (I tested them in black.) You’ll also be fitted with your preferred eartip style (open, closed, or Phonak’s new wax-resistant EasyGuard domes) during your professional evaluation.

These prescription hearing aids worked quite well across the board in my testing. Tuned professionally by a Phonak representative, their claims of hearing better in noisy conditions were accurate, mildly—though not transformatively—dulling background sound in most cases. It’s nearly impossible to quantify exactly how much better the Ultra Sphere aids worked compared to other models on this front. Oddly, they worked better in noise than they did in relative silence. In a quiet room, the hearing aids would occasionally hiss gently for a few seconds, then stop, only to hiss again a few minutes later. This light hiss effect was sustained throughout my experience, but I could only detect it when there wasn’t any other noise in the room.