Otofonix Helix vs Phonak Audéo EON Sphere
Side-by-side HearAdvisor lab results with SoundGrades, expert pick badges, and the same visualizations we use in product reviews.

Otofonix Helix
The Otofonix Helix is a behind-the-ear amplification product priced at $695, earning a C grade with a SoundScore of 2.7/5 in our lab testing. This places it in the lower tier of the amplification product category, ranking #7 of 8 devices tested. In our standardized testing, the Helix demonstrates one clear strength: excellent feedback handling, scoring a perfect 5.0/5—well above the category average. This means users can expect stable performance without whistling or squealing during normal wear and head movements. However, the Helix shows significant limitations in other areas. Speech clarity scores are low in both quiet (1.0/5) and noisy (1.0/5) environments, falling below category averages by 1.11 and 0.37 points respectively. Music streaming capability scored 0.0/5, indicating this device is not suitable for those who want to stream audio content. Own-voice comfort is also a weakness, particularly in the tuned configuration. At this price point, consumers should be aware that several alternatives in the same range offer stronger overall performance. The Otofonix Helix may appeal to those who prioritize feedback-free operation above other factors, but those seeking better speech understanding or streaming functionality should explore other options in the amplification product category.
Choice

Phonak Audéo EON Sphere
The Phonak Audéo EON Sphere is a premium behind-the-ear prescription hearing aid priced at $4,398. In HearAdvisor's lab testing, it earned a SoundScore of 5.0/5 and an A grade, placing it among the top performers in the prescription hearing aid category. Speech performance stands out as this device's greatest strength. Speech in noise scored an excellent 4.5/5, a full 2.53 points above the category average of 1.96/5—a substantial margin that makes this one of the strongest performers in challenging listening environments. Speech in quiet also performed well at 4.3/5, nearly a full point above the category average. These results suggest the Audéo EON Sphere may be particularly well-suited for users who frequently encounter noisy social settings or group conversations. Music streaming delivered a solid 3.7/5, more than a point above the category average of 2.64/5, indicating above-average audio fidelity for phone-streamed content. Own-voice comfort scored 2.8/5, which sits just above the category average but reflects mixed absolute performance—users sensitive to occlusion effects should discuss this with their hearing care provider. Feedback handling scored an excellent 4.6/5 in absolute terms, though it lands slightly below the category average of 4.71/5. The Audéo EON Sphere represents Phonak's latest premium technology and delivers strong results across most metrics in our standardized testing. It's best suited for users prioritizing speech clarity in difficult listening situations who are prepared for the premium price point.
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