Autiphon U0 Series vs MDHearing VoltMax
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.

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.
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