These are not really the same size class, and that is the honest framing here. The Soundcore Boom Go 3i ranks #2 of 62 small speakers by sound quality at $59.98; the Sony ULT Field 3 ranks #71 of 179 medium speakers by sound quality at $208.
The Soundcore Boom Go 3i is the lighter choice. A tough, floating mini speaker with full waterproofing, a long battery and a detachable strap, built for travel and the outdoors. At 0.8 lbs (380 g) it weighs much less than the Sony ULT Field 3 at 2.6 lbs (1.2 kg). The tradeoff: This is still a 15W mono speaker: bass impact and stereo width are limited, and critical listeners may find the upper treble piercing or metallic.
Why pick the Sony ULT Field 3: A rugged waterproof stereo speaker with long battery life, a detailed app EQ, a shoulder strap and a phone charging port. It supports LDAC Bluetooth, which the Soundcore Boom Go 3i lacks. It plays in stereo from a single unit, unlike the Soundcore Boom Go 3i. The catch: Sounds a bit hollow, a bit boosted in the treble.
Buy the Soundcore Boom Go 3i ($59.98) for a small speaker; the Sony ULT Field 3 ($208) suits a medium speaker instead.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Prices on this page were last checked November 7, 2026 at 7:34 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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Specifications Side By Side
| Soundcore Boom Go 3i | Sony ULT Field 3 | |
|---|---|---|
| Price | $59.98 | $208.00 |
| Ranked | #2 of 62 in Small Size Portable Bluetooth Speakers | #71 of 179 in Medium Size Portable Bluetooth Speakers |
| App | Yes | Yes |
| Aux Input | No | No |
| Battery Life | 24 hours (Manufacturer specified) | 24 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC, AAC, LDAC |
| Built-in Microphone | Yes | Yes |
| EQ | Yes | Yes (App + ULT button) |
| IP Rating | IP68 | IP67 |
| Party Mode | Yes (Auracast) | Yes (Party Connect up to 100 speakers) |
| Power Bank | Yes (USB-C) | Yes (USB-C, 5V/1.5A) |
| Power Input | USB-C | USB-C |
| Stereo | No | Yes |
| Omnidirectional | Pointing up | No |
| TWS | Yes | Yes |
| Weight | 0.8 lbs (380 g) | 2.6 lbs (1.2 kg) |
| Bluetooth Version | 6.0 | 5.2 |
| Amplifier Power | 15W | 27W |
| Dimensions | 4” x 4.2” x 1.8” (102.1 x 105.9 x 45.5 mm) | 10.1” x 4.4” x 3.1” (256 x 113 x 79 mm) |
| Drivers | 25mm tweeter + 42mm woofer + passive radiators | 1x 20mm tweeter + 1x 86mm x 46mm woofer |
| Maximum SPL | 92dB (Manufacturer specified) | - |
| Digital Aux Input | No | No |
| Lights | Yes | - |
| Strap | Yes (detachable strap) | Yes (detachable shoulder strap) |
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