MDHearing Volt 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 Volt
The MDHearing Volt is a budget-priced prescription hearing aid available for $397, earning a B grade with a SoundScore of 3.1/5 in our lab testing. This behind-the-ear, rechargeable device ranks #32 of 36 prescription hearing aids tested, placing it in the top 86% of its category. In our standardized testing, the Volt demonstrates excellent feedback handling at 5.0/5, scoring 0.29 points above the category average. This represents a genuine strength, as the device remained stable under our challenge protocols without audible squealing or whistling. However, speech performance presents significant limitations: speech in quiet scored 1.8/5 (1.57 points below the category average of 3.32), while speech in noise scored 1.0/5 (0.96 points below the 1.96 average). Own-voice comfort measured 2.6/5, a mixed result that falls 0.15 points below the category average. Music streaming is notably limited at 0.0/5, scoring 2.64 points below the category average—users prioritizing phone streaming should consider alternatives. The Volt showed no improvement between Initial and Tuned fits, with both configurations yielding identical scores of 3.1/5. The MDHearing Volt may suit budget-conscious consumers who prioritize basic amplification and excellent feedback stability over speech clarity or streaming features. However, shoppers in this price range should note that alternatives like the RxEars Rxi offer substantially higher performance at similar pricing.
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)
Fitting configuration for tuned fit