Autiphon U0 Series vs Signia Styletto AX
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 priced at $99, earning a C grade with a SoundScore of 2.9/5 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 a mixed performance profile. Its standout strength is excellent feedback handling, scoring a perfect 5.0/5—well above the category average by 0.72 points. This means users are unlikely to experience whistling or squealing during normal use. Speech in quiet environments scores 2.3/5, which is 0.22 points above the category average, though still 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—meaning challenging listening environments like restaurants or gatherings will be difficult. Music streaming capability is essentially non-functional, scoring 0.0/5 and sitting 1.16 points below category average. The Autiphon U0 Series is best suited for budget-conscious users who primarily need basic amplification in quieter settings and prioritize freedom from feedback issues. Those who frequently encounter noisy environments or want to stream music should consider alternatives. At this price point, the HSKLock Hearing Aid offers slightly higher overall performance at 2.98/5.
Choice

Signia Styletto AX
The Signia Styletto AX is a premium prescription behind-the-ear hearing aid that earned an A grade with a SoundScore of 4.3/5 in our lab testing, ranking #21 of 39 prescription hearing aids tested. Priced at $4,398, this 2022 release features a distinctive slim design with rechargeable batteries and iPhone streaming capability. In our testing, the Styletto AX demonstrated strong speech clarity in quiet environments, scoring 4.0/5—0.63 points above the category average. Speech in noise performance was above average at 2.3/5 (+0.17 vs category), though this remains mixed in absolute terms, suggesting challenging listening situations may still require additional strategies. Own-voice comfort scored a solid 3.0/5, sitting 0.30 points above average. Music streaming quality measured 3.1/5, performing 0.34 points above the category average for solid audio fidelity when streaming from compatible devices. Feedback handling scored 3.9/5—solid in absolute terms, though 0.82 points below the category average of 4.72/5, which is worth noting if feedback stability is a priority. The Styletto AX has earned Expert's Choice Awards in both 2023 and 2024. However, buyers in this premium price tier should be aware that several competitors offer higher SoundScores, including the Phonak Sphere Infinio (4.98/5) and Oticon Intent (4.83/5). The Styletto AX may appeal most to those prioritizing its sleek aesthetic and strong quiet-environment speech performance over maximum scores in noise or feedback handling.
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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
Recorded samples (Tuned)
Fitting configuration for tuned fit