Short answer: the Sony ULT Field 5. It ranks #41 of 78 large speakers by sound quality at $198; the Marshall Stockwell III ranks #56 and costs $249.99, which makes this an easy call rather than a real tradeoff.
What the Sony ULT Field 5 offers: A tough 3.3kg portable with IP67 protection, LDAC/AAC support, aux input, a 10-band app EQ, Party Connect, USB-C power-bank output and a claimed 25-hour battery. Reviews find it energetic and dynamic with substantial bass, enough volume for a yard, and two ULT modes that let bass-focused listeners choose a deeper or punchier presentation. Watch for: It prioritizes bass and loudness over fidelity: reviews find the upper mids and highs subdued, with limited stereo separation and soundstage depth. Deep bass is less authoritative than the enclosure suggests, and the loud confirmation tone when pressing the ULT button is an unnecessary annoyance. Use the app EQ and audition it before buying for detail-focused music.
What the Marshall Stockwell III offers: 40+ hour battery life with a user-replaceable battery, strap, sleeve and grilles. Doubles as a USB-C power bank. IP55 dust/water resistance. App includes parametric EQ, a Soundstage widening control, and wall/corner placement compensation. Endless-rotation control knobs. Watch for: Highs are recessed by default and need the treble control maxed to compensate, still lacking detail even then. Bass tends to sound resonant and boomy, with reported frequency cancellation and phase issues on complex material that EQ doesn’t fully resolve. Oluv’s A/B testing against the outgoing Stockwell 2 finds the default tuning muffled and muddy enough to prefer the seven-year-old original out of the box, and output loses dynamics and bass while turning harsh well below maximum volume. No aptX support.
Buy the Sony ULT Field 5. It ranks higher for sound quality than the Marshall Stockwell III and costs less, so there is no real case for the other one.
Battery life favors the Marshall Stockwell III: rated for 40 hours against 25 hours for the Sony ULT Field 5.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Sony ULT Field 5 | Marshall Stockwell III | |
|---|---|---|
| Price | $198 | $249.99 |
| Ranked | #41 of 78 in Large Size Portable Bluetooth Speakers | #56 of 78 in Large Size Portable Bluetooth Speakers |
| App | Yes | Yes |
| Aux Input | Yes | Yes |
| Battery Life | 25 hours (Manufacturer specified) | 40+ hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, AAC, LDAC | SBC, AAC, LE Audio with LC3 |
| Bluetooth Version | 5.3 | 5.3 |
| Built-in Microphone | Yes | - |
| Dimensions | 12.6" x 5.7" x 4.9" (320 x 144 x 125 mm) | 7.1" x 6.4" x 2.9" (180 x 162 x 74 mm) |
| Drivers | 2x 46mm tweeters + 1x 79mm x 107mm 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) | Yes |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Partially |
| Omnidirectional | No | Yes |
| TWS | Yes | - |
| Weight | 7.3 lbs (3.3 kg) | 2.9 lbs (1.3 kg) |
| Amplifier Power | 27W | 44W |
| Digital Aux Input | No | No |
| Frequency Response | - | 54Hz - 20kHz (Manufacturer specified) |
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Prices on this page were last checked September 16, 2026 at 12:41 AM 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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The Two Speakers In Full
Sony ULT Field 5: $198 Amazon eBay
Pros: A tough 3.3kg portable with IP67 protection, LDAC/AAC support, aux input, a 10-band app EQ, Party Connect, USB-C power-bank output and a claimed 25-hour battery. Reviews find it energetic and dynamic with substantial bass, enough volume for a yard, and two ULT modes that let bass-focused listeners choose a deeper or punchier presentation.
Cons: It prioritizes bass and loudness over fidelity: reviews find the upper mids and highs subdued, with limited stereo separation and soundstage depth. Deep bass is less authoritative than the enclosure suggests, and the loud confirmation tone when pressing the ULT button is an unnecessary annoyance. Use the app EQ and audition it before buying for detail-focused music.
Full Sony ULT Field 5 review and specifications →
| Amplifier Power | 27W |
|---|---|
| App | Yes |
| Aux Input | Yes |
| Battery Life | 25 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, AAC, LDAC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 12.6" x 5.7" x 4.9" (320 x 144 x 125 mm) |
| Drivers | 2x 46mm tweeters + 1x 79mm x 107mm woofer |
| EQ | Yes (App + ULT button) |
| IP Rating | IP67 |
| Omnidirectional | No |
| Party Mode | Yes (Party Connect up to 100 speakers) |
| Power Bank | Yes (USB-C) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 7.3 lbs (3.3 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Danny Pops: Don’t TOUCH that ULT Button! Sony ULT Field 5 Review More from DannyPops →
- Mark Ellis Reviews: Sony just changed summer sound 🤨 | Sony ULT Field 5 & 3 Review
- Dominik Reviews: Sony ULT Field 5 vs JBL Xtreme 4 - Outdoor Sound Test - Sony shines or not? More from Dominik Reviews →
- Joy & Oluv’Sone: Sony ULT Field 5 vs Anker SoundCore Boom 2 - listening test More from Oluv’Sone →
- Head-to-Head Comparisons
Marshall Stockwell III: $249.99 Marshall eBay
Pros: 40+ hour battery life with a user-replaceable battery, strap, sleeve and grilles. Doubles as a USB-C power bank. IP55 dust/water resistance. App includes parametric EQ, a Soundstage widening control, and wall/corner placement compensation. Endless-rotation control knobs.
Cons: Highs are recessed by default and need the treble control maxed to compensate, still lacking detail even then. Bass tends to sound resonant and boomy, with reported frequency cancellation and phase issues on complex material that EQ doesn’t fully resolve. Oluv’s A/B testing against the outgoing Stockwell 2 finds the default tuning muffled and muddy enough to prefer the seven-year-old original out of the box, and output loses dynamics and bass while turning harsh well below maximum volume. No aptX support.
Full Marshall Stockwell III review and specifications →
| Amplifier Power | 44W |
|---|---|
| App | Yes |
| Aux Input | Yes |
| Battery Life | 40+ hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, AAC, LE Audio with LC3 |
| Bluetooth Version | 5.3 |
| Digital Aux Input | No |
| Dimensions | 7.1" x 6.4" x 2.9" (180 x 162 x 74 mm) |
| Drivers | 1x 3" woofer, 2x 1.75" wide-band drivers |
| EQ | Yes (parametric, via app) |
| Frequency Response | 54Hz - 20kHz (Manufacturer specified) |
| IP Rating | IP55 |
| Omnidirectional | Yes |
| Power Bank | Yes |
| Power Input | USB-C |
| Stereo | Partially |
| Weight | 2.9 lbs (1.3 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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