Autiphon U0 Series vs Phonak Sphere Infinio Ultra
Side-by-side HearAdvisor lab results with SoundGrades, expert pick badges, and the same visualizations we use in product reviews.

Autiphon U0 Series
The Autiphon U0 Series is a budget amplification product available at $99, earning a B grade with a SoundScore of 3.0/5 in HearAdvisor's lab testing. This visible-in-ear device ranks #6 of 8 amplification products tested, placing it in the top 63% of its category. In our testing, the U0 Series demonstrates excellent feedback handling at 5.0/5, scoring 0.72 points above the category average. This means users can expect stable performance without the whistling issues that plague some amplifiers. Speech in quiet environments scores 2.3/5—above the category average by 0.22 points, though only mixed in absolute terms. The device shows notable limitations in other areas. Speech in noise performance is low at 1.0/5, falling 0.37 points below the category average, which may make challenging listening environments difficult. Music streaming is the weakest area at 0.0/5, coming in 1.16 points below category average—users seeking audio streaming functionality should look elsewhere. The Autiphon U0 Series is best suited for budget-conscious consumers who primarily need basic amplification in quieter settings and prioritize reliable, feedback-free operation over advanced features. The rechargeable batteries add convenience at this price point. However, those who frequently encounter noisy environments or want to stream music should consider alternatives despite the higher cost.
Choice

Phonak Sphere Infinio Ultra
The Phonak Sphere Infinio Ultra is a premium behind-the-ear prescription hearing aid priced at $4,898. In HearAdvisor's lab testing, it earned an A grade with a SoundScore of 4.9/5, placing it in the top 3% of the 36 prescription hearing aids tested and ranking #2 in its category. This device delivers exceptional speech performance in our testing. Speech in noise scored an excellent 4.5/5, a remarkable 2.55 points above the category average of 1.96/5—one of the largest margins we've measured in this critical metric. Speech in quiet also performed strongly at 4.3/5, exceeding the category average by 1.00 point. These results suggest the Sphere Infinio Ultra prioritizes speech clarity across challenging listening environments. Music streaming quality is solid at 3.3/5, sitting 0.66 points above the category average. Own voice comfort scored 2.8/5, which is above the category average but remains mixed in absolute terms—listeners sensitive to occlusion may notice this limitation. Feedback handling measured 4.2/5, which is strong in absolute terms though 0.51 points below the category average of 4.71/5. The Sphere Infinio Ultra is best suited for users who prioritize speech understanding, particularly in noisy environments, and who are prepared to invest in premium technology. Those seeking the highest feedback stability or improved own-voice comfort may want to compare alternatives, though this device's speech performance stands out as a category leader.
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Performance metrics
Scale 1-5 (Tuned)
Lab metric by fit
Scale 1-5 (Tuned)
Speech level
Adjust input dB (Tuned)
Amplification (REIG)
Insertion gain at 65 dB (Tuned)
Audio scenes
Using MUSHRA scenes (Tuned)
Fitting configuration for tuned fit