MDHearing VoltMax vs Olive Union Max
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.

Olive Union Max
The Olive Union Max is a behind-the-ear OTC hearing aid priced at $190, earning a B grade with a SoundScore of 3.4/5 in HearAdvisor's lab testing. This budget-friendly device ranks #41 of 65 OTC hearing aids tested. In our lab testing, the Max shows a distinctive performance profile with clear strengths and limitations. Music streaming stands out with a strong 4.0/5 score, measuring 2.08 points above the OTC category average—making it one of the better choices for audio entertainment. Feedback handling is excellent at 5.0/5, meaning the device maintains stability without whistling during typical daily activities. However, speech performance presents challenges. Speech in quiet scores a mixed 2.6/5, falling 0.21 points below the category average, while speech in noise is low at 1.0/5, measuring 0.48 points below average. Own-voice comfort also scores low at 1.6/5, sitting 0.91 points below the category average—users may notice their own voice sounds unnatural or hollow. The Olive Union Max is best suited for budget-conscious consumers who prioritize music and media streaming over demanding listening environments. Those who frequently need to follow conversations in noisy settings like restaurants or social gatherings may find the speech-in-noise limitations frustrating. For basic amplification in quieter environments with excellent streaming quality at an accessible price point, the Max offers reasonable value despite its speech performance trade-offs.
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