Olive Union Air 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.

Olive Union Air
The Olive Union Air is a budget-priced OTC hearing aid that earned a B grade with a SoundScore of 3.9/5 in our lab testing, placing it in the top 31% of OTC hearing aids at #21 of 65 devices tested. At $250, it represents a competitive entry point in the over-the-counter hearing aid market. In our testing, this visible-in-ear style device demonstrated notable strengths in music streaming, scoring 3.6/5—a solid result that sits 1.67 points above the OTC category average. Feedback handling was excellent at 5.0/5, meaning users should experience minimal whistling or squealing during normal use. Speech understanding in quiet environments also performed well at 3.3/5, measuring 0.46 points above the category average. The Olive Union Air does show limitations in more challenging listening situations. Speech in noise scored 1.0/5, falling 0.48 points below the category average—a common weakness among budget OTC devices that may affect conversations in restaurants or busy environments. Own-voice comfort measured 2.2/5, slightly below average, which some users may notice when speaking. This device is best suited for individuals who prioritize music and media streaming, need reliable feedback control, and primarily listen in quieter environments. Those who frequently encounter noisy social situations may want to consider devices with stronger speech-in-noise performance.
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