Phonak Sphere Infinio vs Signia Styletto AX
Side-by-side HearAdvisor lab results with SoundGrades, expert pick badges, and the same visualizations we use in product reviews.
Choice

Phonak Sphere Infinio
The Phonak Sphere Infinio is a premium prescription behind-the-ear hearing aid released in 2024, priced at $4,898. In HearAdvisor's lab testing, it achieved a SoundScore of 5.0/5 and an A grade, ranking #1 among 36 prescription hearing aids tested. This device delivers exceptional speech performance, particularly in challenging listening environments. Speech in noise scored an excellent 4.7/5, measuring 2.74 points above the category average—a substantial margin that sets it apart from competitors. Speech in quiet also performed strongly at 4.5/5, sitting 1.15 points above average. Music streaming earned a strong 4.0/5, exceeding the category average by 1.36 points. The Sphere Infinio does show some trade-offs. Feedback handling scored a solid 3.6/5 in absolute terms, though this falls 1.11 points below the category average of 4.71/5. Own-voice comfort scored a mixed 2.3/5, slightly below the category average. These are areas where some competing premium devices perform better. This hearing aid is best suited for those who prioritize speech clarity, especially in noisy environments like restaurants or social gatherings. The behind-the-ear style offers rechargeable batteries and streaming compatibility with both iPhone and Android devices. Among premium-priced competitors like the Oticon Intent (4.85/5) and Oticon Real (4.75/5), the Sphere Infinio leads in overall sound performance, earning HearAdvisor's Expert's Choice Award for 2024 and 2023.
Choice

Signia Styletto AX
The Signia Styletto AX is a premium prescription behind-the-ear hearing aid released in 2022, priced at $4,398. In HearAdvisor's lab testing, it earns an A grade with a SoundScore of 4.3/5, ranking #19 among 36 prescription hearing aids tested. This device demonstrates strong speech-in-quiet performance at 4.0/5, scoring 0.71 points above the category average. Speech-in-noise shows mixed absolute results at 2.3/5, though this still sits 0.32 points above the category average of 1.96/5. Music streaming quality is solid at 3.1/5, exceeding the category average by 0.46 points—a meaningful advantage for users who frequently stream audio from their iPhone. Own-voice comfort scores a solid 3.0/5, slightly above category average. However, feedback handling at 3.9/5 falls 0.81 points below the category average of 4.71/5—solid in absolute terms but notably weaker than many prescription competitors in our testing. The Styletto AX has earned HearAdvisor's Expert's Choice Award in both 2023 and 2024. With its distinctive slim design, rechargeable batteries, and iPhone streaming capabilities, it may appeal to users prioritizing aesthetics and convenience alongside strong speech clarity in quieter environments. Those frequently in challenging noise situations or requiring maximum feedback stability may want to compare alternatives in this price tier.
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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