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

HSKLock Hearing Aid
The HSKLock Hearing Aid is a budget-priced amplification product available for $69, earning a B grade with a SoundScore of 3.0/5 in our lab testing. This behind-the-ear device uses disposable batteries and ranks #5 of 8 amplification products tested. In our testing, the HSKLock delivered excellent feedback handling at 5.0/5, scoring 0.72 points above the category average. This means users can expect stable performance without whistling during typical wear. Own-voice comfort scored 2.8/5, slightly above the category average but only mixed in absolute terms. However, speech clarity presents significant limitations. Speech in quiet scored 1.5/5, falling 0.63 points below the category average, while speech in noise measured 1.0/5, which is 0.37 points below average. Music streaming scored 0.0/5, well below the already-low category average of 1.16/5, making this device unsuitable for audio entertainment purposes. The HSKLock may appeal to budget-conscious consumers seeking basic amplification with reliable feedback control. Those prioritizing speech understanding or music quality should consider alternatives. At this price point, competitors like the Autiphon U0 Series offer similar overall performance, though each device has distinct trade-offs in specific metrics.

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