Linner Mars vs Sennheiser All-Day Clear Slim
Side-by-side HearAdvisor lab results with SoundGrades, expert pick badges, and the same visualizations we use in product reviews.

Linner Mars
The Linner Mars is a budget-priced OTC hearing aid that earns a B grade with a SoundScore of 3.1/5 in our lab testing. At $399, it falls in the lowest price tier for OTC devices, though its overall sound performance ranks #55 of 65 in the OTC Hearing Aid category. This device presents a stark contrast in performance across different listening situations. Music streaming is a genuine standout, scoring an excellent 4.6/5—well above the category average. Feedback handling also earns a perfect 5.0/5, meaning users shouldn't experience whistling or squealing issues. However, the Mars struggles significantly with its core hearing aid function: speech clarity. Speech in quiet scores just 1.9/5, and speech in noise drops to 1.0/5, both falling below category averages. Own-voice comfort is another weak point at 1.0/5, which is 1.51 points below the category average. Users may find their own voice sounds unnatural or boomy when wearing these devices. The tuned fit shows modest improvement over the initial fit (3.4/5 vs 3.1/5), primarily through better speech-in-quiet performance. The Linner Mars may appeal to budget-conscious consumers who prioritize music and media streaming over speech understanding. However, several competitors in the same price range—including the Elehear Beyond and Apple AirPods Pro 2—offer substantially better overall sound performance. Those seeking improved speech clarity should consider alternatives that score higher in that critical area.
Choice

Sennheiser All-Day Clear Slim
The Sennheiser All-Day Clear Slim is a premium OTC behind-the-ear hearing aid priced at $1,499, earning an A grade with a SoundScore of 4.1/5. This places it in the top 23% of OTC hearing aids tested in our lab, ranking #16 among 65 devices in its category. This device excels in areas that reflect Sennheiser's audio heritage. Music streaming quality is a standout strength, scoring 3.8/5—a solid result that's 1.88 points above the OTC category average. Feedback handling is excellent at 5.0/5, meaning users can expect stability without whistling during typical use. Speech in quiet environments also performs well at 3.6/5, sitting 0.85 points above average for the category. However, the All-Day Clear Slim shows limitations in other areas. Speech in noise scores 1.5/5, matching the category average but representing a low absolute score that may challenge users in noisy restaurants or group conversations. Own-voice comfort is below average at 1.9/5, which could affect how natural users sound to themselves during conversation. The All-Day Clear Slim is best suited for consumers who prioritize music streaming and media consumption alongside hearing support, and who spend more time in quieter environments. Those frequently navigating noisy social situations may want to compare against higher-ranked competitors in this price range, such as the Lucid Tala or Audicus Omni 2, which achieve stronger overall scores.
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