These are not really the same size class, and that is the honest framing here. The Sony ULT Field 3 ranks #71 of 179 medium speakers by sound quality at $208; the Marshall Stockwell III ranks #84 of 120 large speakers by sound quality at $249.99.
The Sony ULT Field 3 is the tougher pick. A rugged waterproof stereo speaker with long battery life, a detailed app EQ, a shoulder strap and a phone charging port. It is rated IP67 against IP55 for the Marshall Stockwell III. It supports LDAC Bluetooth, which the Marshall Stockwell III lacks. Watch for: Sounds a bit hollow, a bit boosted in the treble.
The Marshall Stockwell III is the longer-running pick. A stylish, rugged speaker with a very long battery you can swap yourself, a detailed app EQ, and power bank charging. It is rated for 40 hours of battery against 24 for the Sony ULT Field 3. It keeps a wired aux input, which the Sony ULT Field 3 lacks. The tradeoff: Highs are recessed by default and need the treble control maxed to compensate, still lacking detail even then.
Buy the Sony ULT Field 3 at $208 for a medium speaker, or the Marshall Stockwell III at $249.99 for a large speaker instead.
Looking for alternatives? See the complete Portable Bluetooth rankings.
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Specifications Side By Side
| Sony ULT Field 3 | Marshall Stockwell III | |
|---|---|---|
| Price | $208.00 | $249.99 |
| Ranked | #71 of 179 in Medium Size Portable Bluetooth Speakers | #84 of 120 in Large Size Portable Bluetooth Speakers |
| App | Yes | Yes |
| Aux Input | No | Yes |
| Battery Life | 24 hours (Manufacturer specified) | 40+ hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC, AAC, LDAC | SBC, AAC, LE Audio with LC3 |
| Bluetooth Version | 5.2 | 5.3 |
| Built-in Microphone | Yes | - |
| Dimensions | 10.1” x 4.4” x 3.1” (256 x 113 x 79 mm) | 7.1” x 6.4” x 2.9” (180 x 162 x 74 mm) |
| Drivers | 1x 20mm tweeter + 1x 86mm x 46mm woofer | 1x 3” woofer, 2x 1.75” wide-band drivers |
| EQ | Yes (App + ULT button) | Yes (parametric, via app) |
| IP Rating | IP67 | IP55 |
| Party Mode | Yes (Party Connect up to 100 speakers) | - |
| Power Bank | Yes (USB-C, 5V/1.5A) | Yes |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Partially |
| Omnidirectional | No | Yes |
| TWS | Yes | No |
| Weight | 2.6 lbs (1.2 kg) | 2.9 lbs (1.3 kg) |
| Amplifier Power | 27W | 44W |
| Digital Aux Input | No | No |
| Strap | Yes (detachable shoulder strap) | Yes (detachable strap) |
| Frequency Response | - | 54Hz - 20kHz (Manufacturer specified) |
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