Overview

The Beats Solo 4 are wireless Bluetooth on-ear headphones released in May 2024, priced at 199 USD. Featuring custom 40mm drivers, 50-hour battery life, and support for lossless audio via USB-C, these headphones represent Beats’ latest iteration of their popular Solo series. The Solo 4 maintains the signature Beats aesthetic while incorporating improved acoustic architecture and Spatial Audio with dynamic head tracking.

Scientific Validity

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The Solo 4 exhibits significant deviations from neutral frequency response. Third-party measurements reveal underemphasis from 20Hz through 800Hz, followed by overemphasis from 3kHz to 9kHz [1]. The bass response, while deep, lacks precision and control, with reviewers noting it can be “impactful at times but wooly at others” [2]. The lower mids experience problematic muddiness, though upper mids maintain acceptable clarity. The treble response heavily favors higher frequencies, creating an unbalanced presentation that prioritizes brightness over accuracy. Objective listening algorithm results (MDAQS, HEAD acoustics) in Default mode report: Timbre 4.3, Distortion 3.0, Immersiveness 3.2, Overall 3.9 [1]. The Solo 4 does not offer ANC and—typical of on-ear designs—passive isolation is modest [1]. No independent THD, SNR, or distortion measurements were publicly available, limiting objective assessment of transparency criteria.

Technology Level

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The Solo 4 features custom-built 40mm transducers designed to minimize electronic artifacts and distortion. The upgraded acoustic architecture incorporates passive tuning, typically reserved for higher-end headphones, to maintain frequency response without artificial boosting. Class 1 Bluetooth 5.3 provides extended range and improved connectivity stability. The headphones support AAC and SBC codecs wirelessly, with lossless audio capability via USB-C or 3.5mm connections. While the engineering represents competent consumer-grade implementation, the technology level remains conventional with no significant innovations distinguishing it from industry standards.

Cost-Performance

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At 199 USD, the Solo 4 faces strong competition from superior alternatives. The Sennheiser ACCENTUM Wireless provides equivalent-or-better user-facing functionality and measured performance at 149.95 USD [4]. Equivalence basis (user perspective): adds hybrid ANC and aptX/aptX HD with USB-C audio; lab isolation reaches 30–40 dB above 1 kHz with ANC contributing ~15–20 dB below 1 kHz; standardized battery test measured 46 h 40 min (50-hour class) [4]. CP calculation: 149.95 USD ÷ 199 USD = 0.75 → 0.8 (rounded to the first decimal).

Reliability & Support

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Beats provides standard 1-year limited warranty coverage with established support infrastructure through Apple. Battery endurance is strong in practice: a standardized test peaking at 75 dBSPL measured 84 hours 18 minutes [1]. Fast Fuel quick charging (5 hours from 10 minutes) adds practical resilience. Build quality appears adequate for the on-ear category, though long-term reliability data for this specific model remains limited due to recent release. The integration with Apple’s ecosystem provides consistent firmware updates and device compatibility, maintaining industry-average support standards.

Rationality of Design Philosophy

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The Solo 4’s design philosophy aims for consumer-friendly sound signature with emphasis on convenience features. The 50-hour battery life and rapid charging address practical user needs effectively. However, the frequency response tuning prioritizes marketing appeal over scientific accuracy, with excessive treble emphasis that deviates significantly from neutral reproduction. The decision to omit advanced codec support (aptX, LDAC) limits high-quality wireless audio capability. While the passive tuning approach shows engineering awareness, the final implementation fails to achieve transparent reproduction, suggesting design priorities favor brand sound signature over scientific validity.

Advice

The Solo 4 is suitable for casual listeners who prioritize brand recognition, battery life, and Apple ecosystem integration over audio accuracy. For users seeking superior sound quality at this price point, the Audio-Technica ATH-M50xBT2 or Sennheiser Accentum Wireless provide measurably better frequency response and overall performance. The Solo 4’s value proposition weakens significantly when compared to alternatives offering equivalent features with superior acoustic performance at equal or lower prices.

References

[1] SoundGuys, “Beats Solo 4 review”, https://www.soundguys.com/beats-solo-4-review-115347/, accessed 2025-08-12, measurement conditions: standard test rig [2] TechRadar, “Beats Solo 4 review: a solid update to an iconic pair of wireless headphones, but the competition is now too hot”, https://www.techradar.com/audio/headphones/beats-solo-4-review, accessed 2025-08-12 [3] RTINGS, “Audio-Technica ATH-M50xBT2 Wireless Review”, https://www.rtings.com/headphones/reviews/audio-technica/ath-m50xbt2-wireless, accessed 2025-08-12, measurement conditions: RTINGS test rig [4] SoundGuys, “Sennheiser ACCENTUM Wireless review”, https://www.soundguys.com/sennheiser-accentum-wireless-review-100972/, accessed 2025-08-12

(2025.8.12)