MDHearing VoltMax vs Sontro Soundwave
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 mid-priced device ranks #62 of 65 in the OTC Hearing Aid category, placing it in the bottom portion of tested products. In our standardized testing, the VoltMax demonstrates excellent feedback handling at 5.0/5, scoring 0.46 points above the category average. This means users are unlikely to experience whistling or squealing during typical wear. However, speech performance presents significant challenges—speech in quiet scores a low 1.9/5 (0.93 points below average), while speech in noise scores 1.0/5 (0.48 points below average). These results suggest limited benefit for understanding conversation in both calm and challenging listening environments. Music streaming is a notable weakness, scoring 0.0/5 and falling 1.92 points below the category average. Users who prioritize streaming audio content from their phones should consider alternatives. Own-voice comfort is mixed at 2.4/5, roughly matching the category average. At this price point, several alternatives offer substantially stronger performance. Devices like the Yeasound RIC800 and Sony CRE-E10 score above 4.5/5 at similar or lower prices. The VoltMax may appeal to users who prioritize feedback-free wear and basic amplification with rechargeable convenience, but those seeking stronger speech clarity should explore higher-performing options in this price range.

Sontro Soundwave
The Sontro Soundwave is a mid-priced OTC hearing aid priced at $849, earning a B grade with a SoundScore of 3.1/5 in HearAdvisor's lab testing. This behind-the-ear device uses disposable batteries and ranks #61 of 65 OTC hearing aids tested, placing it in the top 92% of its category. In our lab testing, the Soundwave shows a notable strength in own-voice comfort, scoring 3.6/5—a solid result that sits 1.09 points above the category average. This suggests users may experience less of the "talking in a barrel" sensation that can occur with some hearing aids. However, the device faces challenges in other key areas. Speech in quiet scores 2.7/5 (mixed, 0.12 points below average), while speech in noise registers at 1.2/5 (low, 0.28 points below average), indicating potential difficulty in challenging listening environments. The most significant limitations appear in music streaming and feedback handling. Music streaming scores 0.0/5, falling 1.92 points below the category average—a notable weakness for users who value audio entertainment. Feedback handling scores 2.5/5, which is 2.04 points below the category average of 4.54/5, suggesting the device may be more prone to whistling issues. At this price point, competitors offer substantially stronger performance. Devices like the Sony CRE-E10 and Lexie B2 Plus deliver significantly higher sound scores in the same price range. The Sontro Soundwave may suit those prioritizing own-voice comfort over speech clarity and streaming quality, but most users would benefit from exploring higher-performing alternatives at similar or lower prices.
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