Overview

The Sony ULT FIELD 5 (SRS-ULT50) is a portable Bluetooth speaker released in April 2025. It features a 2.1ch configuration with an X‑Balanced Speaker Unit using an approx. 79×107 mm woofer and two 46 mm tweeters, with bass enhancement via the ULT button. It offers IP67 water/dust resistance, up to about 25 hours of battery life, and party lighting, and weighs approximately 3.3 kg.

Scientific Validity

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There are no publicly verified measurement datasets available to us (per our standard FR/distortion/MDaQS criteria). In line with policy, the baseline score is set to 0.5.

Reference numeric specs (as far as confirmable)

• Dimensions: approx. 320 × 144 × 125 mm
• Weight: approx. 3.3 kg
• Battery: up to about 25 hours
• IP rating: IP67
• Bluetooth: 5.3 (profiles/codecs not yet confirmed from primary sources)
• Drivers: approx. 79×107 mm woofer ×1, 46 mm tweeters ×2, dual passive radiators

ULT modes intentionally shape bass; a final transparency judgment should be revisited once measurements are available.

Technology Level

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The non-circular X‑Balanced driver design targets lower distortion via larger effective diaphragm area and is now common. Dual passive radiators for bass extension are also standard. App-based EQ and lighting control are available, but remain software-side optimizations; no breakthrough proprietary technology is evident.

Cost-Performance

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Requirement: compare against the world‑lowest priced product that is not inferior in features (equal‑or‑better).

• This product’s observed lowest new price (example): 177 USD
• Equal‑or‑better candidate: Sony ULT FIELD 7 (SRS‑ULT70)
  • Advantages/equality: IP67, battery around 30 h (≥25 h), bass‑boost modes, lighting, party connection, and overall functionality at least equal or better
  • Observed lowest new price (example): 303 USD

Ratio = 303 ÷ 177 ≈ 1.72 → rounded to the ceiling score of 1.0

Reliability & Support

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Sony’s established support and standard warranty apply. IP67 water/dust resistance and up to about 25 hours of playback aid practical reliability. Software updates and settings are handled via the “Sony

Music Center” app. Long‑term failure data is not yet available, so differentiation remains standard.

Rationality of Design Philosophy

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The bass‑focused concept is explicit, with ULT modes deliberately emphasizing low frequencies. This differs from strict Hi‑Fi neutrality, but clearly balances durability (IP67), long battery life, and lighting features. A final sound quality judgment should be revisited once measurements are available.

Advice

ULT FIELD 5 suits use cases prioritizing weather resistance (IP67), long runtime, and portability. If sound quality is your top priority, audition first and verify ULT/EQ settings for your music. Until measurements are available, starting with more neutral settings is a safe choice.

(2025.8.9)