MDHearing VoltMax vs Phonak Sphere Infinio Ultra
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.
Choice

Phonak Sphere Infinio Ultra
The Phonak Sphere Infinio Ultra is a premium behind-the-ear prescription hearing aid priced at $4,898. In HearAdvisor's lab testing, it earned an A grade with a SoundScore of 4.9/5, placing it in the top 3% of the 36 prescription hearing aids tested and ranking #2 in its category. This device delivers exceptional speech performance in our testing. Speech in noise scored an excellent 4.5/5, a remarkable 2.55 points above the category average of 1.96/5—one of the largest margins we've measured in this critical metric. Speech in quiet also performed strongly at 4.3/5, exceeding the category average by 1.00 point. These results suggest the Sphere Infinio Ultra prioritizes speech clarity across challenging listening environments. Music streaming quality is solid at 3.3/5, sitting 0.66 points above the category average. Own voice comfort scored 2.8/5, which is above the category average but remains mixed in absolute terms—listeners sensitive to occlusion may notice this limitation. Feedback handling measured 4.2/5, which is strong in absolute terms though 0.51 points below the category average of 4.71/5. The Sphere Infinio Ultra is best suited for users who prioritize speech understanding, particularly in noisy environments, and who are prepared to invest in premium technology. Those seeking the highest feedback stability or improved own-voice comfort may want to compare alternatives, though this device's speech performance stands out as a category leader.
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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
Using MUSHRA scenes (Tuned)
Fitting configuration for tuned fit