Linner Mercury 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.

Linner Mercury
The Linner Mercury is a budget OTC hearing aid priced at $387, earning a B grade with a SoundScore of 3.0/5 in our lab testing. This visible-in-ear style device ranks #60 of 65 in the OTC Hearing Aid category, positioning it in the lower tier of available options. In our standardized testing, the Mercury demonstrates excellent feedback handling at 4.7/5, scoring 0.16 points above the category average. This means users are unlikely to experience whistling or squealing during typical wear. However, the device shows limitations in other key areas. Speech in quiet scores 2.2/5, falling 0.62 points below the category average, while speech in noise performance is low at 1.0/5, sitting 0.48 points below average. Own-voice comfort is also low at 1.6/5, measuring 0.91 points below the category average. The most significant limitation is music streaming, which scores 0.0/5—a full 1.92 points below the category average. Users who plan to stream phone calls or music through their hearing aids should consider alternatives. At this price point, competitors like the Elehear Beyond and Apple AirPods Pro 2 offer substantially higher overall scores. The Linner Mercury may suit budget-conscious first-time users who prioritize stable, feedback-free wear over streaming capabilities or challenging listening environments. However, those seeking better speech clarity or music quality should explore other options in this price range.
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 5% of the 39 prescription hearing aids tested and ranking #3 in the category. This device demonstrates exceptional speech performance in our testing. Speech in noise scored 4.5/5—an excellent result that measures 2.40 points above the category average of 2.11/5. Speech in quiet also performed strongly at 4.3/5, which is 0.92 points above the category average. These results suggest the Sphere Infinio Ultra may particularly benefit users who frequently navigate challenging listening environments like restaurants or group conversations. Music streaming delivered a solid 3.3/5, measuring 0.54 points above category average. Own-voice comfort scored 2.8/5, which is above the category average by 0.10 points but remains mixed in absolute terms. Feedback handling measured 4.2/5—strong in absolute terms, though 0.52 points below the category average of 4.72/5. The Sphere Infinio Ultra is best suited for users seeking top-tier speech clarity who prioritize performance in noisy environments and are prepared to invest at the premium price tier. Those seeking similar sound quality at a lower price point may also consider the Phonak Sphere Infinio, which scored 4.98/5 in our testing.
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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)
Fitting configuration for tuned fit