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

MDHearing VoltMax
The MDHearing VoltMax is a behind-the-ear OTC hearing aid priced at $699, earning a B grade with a SoundScore of 3.0/5 in our lab testing. This places it in the lower tier of the OTC hearing aid category, ranking 62nd out of 65 devices tested. In our testing, the VoltMax delivered mixed results across key performance areas. Its standout strength is excellent feedback handling, scoring a perfect 5.0/5—above the category average by 0.46 points. This means users can expect stable performance without whistling or squealing during typical daily activities. However, speech clarity proved challenging, with speech-in-quiet scoring 1.9/5 (0.93 points below category average) and speech-in-noise at 1.0/5 (0.48 points below average). Own-voice comfort measured 2.4/5, slightly below the category norm. A significant limitation is music streaming, which scored 0.0/5—nearly 2 points below the category average. Users who prioritize phone streaming for calls or media should consider alternatives. The device features rechargeable batteries, offering convenience over disposable options. At this price point, several competitors deliver substantially stronger overall performance. The VoltMax may appeal to budget-conscious consumers who primarily need basic amplification with reliable feedback control and don't require streaming capabilities. Those seeking better speech clarity or music streaming should explore higher-scoring options in this price range.
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