Short answer: the Marshall Kilburn III. It ranks #41 of 97 large speakers by sound quality, rated 3.8/5, at $379.99. The Sony ULT Field 5 ranks #52, rated 3.5/5, at $348, $31.99 cheaper, a saving that is not big enough to make up the sound-quality gap.
The Marshall Kilburn III is the longer-running option. Spacious soundstage with broad stereo dispersion from Marshall’s True Stereophonic multi-driver layout, delivering warm, room-filling sound with 45Hz bass extension. It is rated for 50 hours of battery against 25 for the Sony ULT Field 5. The tradeoff: Noticeable dips in the midrange compromise frequency response neutrality, making vocals and acoustic instruments sound somewhat recessed or muffled compared to more linear competitors like the JBL Xtreme 4 unless the bass dial is dialed back.
The Sony ULT Field 5 is the tougher option. A tough 7.3 lbs (3.3 kg) 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. It is rated IP67 against IP54 for the Marshall Kilburn III. It supports LDAC Bluetooth, which the Marshall Kilburn III lacks. The tradeoff: It prioritizes bass and loudness over fidelity: reviews find the upper mids and highs subdued, with limited stereo separation and soundstage depth.
Buy the Marshall Kilburn III. It is rated higher for sound quality, and the $31.99 saving on the Sony ULT Field 5 is not enough to make up the difference.
Want more options? Browse the full Portable Bluetooth rankings.
Specifications Side By Side
| Marshall Kilburn III | Sony ULT Field 5 | |
|---|---|---|
| Price | $379.99 | $348.00 |
| Ranked | #41 of 97 in Large Size Portable Bluetooth Speakers | #52 of 97 in Large Size Portable Bluetooth Speakers |
| Amplifier Power | 50W | 27W |
| App | Yes | Yes |
| Aux Input | Yes | Yes |
| Bass Extension (-10dB) | 45Hz | - |
| Battery Life | 50 hours (Manufacturer specified) | 25 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC, AAC | SBC, AAC, LDAC |
| Bluetooth Version | 5.3 | 5.3 |
| Built-in Microphone | No | Yes |
| Digital Aux Input | No | No |
| Dimensions | 10.7” x 5.9” x 6.7” (272 x 150 x 170 mm) | 12.6” x 5.7” x 4.9” (320 x 144 x 125 mm) |
| Drivers | 1x 4” woofer + 2x 2” full-range drivers | 2x 46mm tweeters + 1x 79mm x 107mm woofer |
| EQ | Yes | Yes (App + ULT button) |
| Frequency Response | 45Hz - 20kHz | - |
| IP Rating | IP54 | IP67 |
| Maximum SPL | 91dB | - |
| Omnidirectional | No | No |
| Party Mode | Yes (Auracast) | Yes (Party Connect up to 100 speakers) |
| Power Bank | Yes | Yes (USB-C) |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Yes |
| Strap | Yes (built-in strap) | Yes (detachable shoulder strap) |
| TWS | Yes | Yes |
| Weight | 6.3 lbs (2.85 kg) | 7.3 lbs (3.3 kg) |
Related Speaker Comparisons
How Marshall Kilburn III compares with other leading options:
- JBL Xtreme 5 vs Marshall Kilburn III
- Tribit Stormbox Lava vs Marshall Kilburn III
- Brane X vs Marshall Kilburn III
- Soundcore Boom 2 vs Marshall Kilburn III
- Marshall Stockwell II vs Marshall Kilburn III
Prices on this page were last checked October 2, 2026 at 10:18 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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The Two Speakers In Full
Marshall Kilburn III: $379.99 Amazon eBay
Older model: the Marshall Kilburn II (ranked lower, rated 3.8/5).
Pros: Spacious soundstage with broad stereo dispersion from Marshall’s True Stereophonic multi-driver layout, delivering warm, room-filling sound with 45Hz bass extension. Independent physical bass and treble dials allow quick tonal adjustments on the fly, backed by app-based EQ and placement compensation. Battery life is outstanding at up to 50+ hours with USB-C power-bank charging, IP54 splash resistance, 3.5mm aux input, and Bluetooth 5.3 with Auracast broadcast support. Measured bass extension of 45Hz (-10dB).
Cons: Noticeable dips in the midrange compromise frequency response neutrality, making vocals and acoustic instruments sound somewhat recessed or muffled compared to more linear competitors like the JBL Xtreme 4 unless the bass dial is dialed back. Kilburn II retains slightly punchier perceived loudness at maximum volume due to a more aggressive V-shaped contour. At 2.85 kg with only IP54 splash resistance, it is heavy and cannot withstand water immersion. Lacks a built-in microphone and LDAC codec support.
Full Marshall Kilburn III review and specifications →
| Amplifier Power | 50W |
|---|---|
| App | Yes |
| Aux Input | Yes |
| Bass Extension (-10dB) | 45Hz |
| Battery Life | 50 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC, AAC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 10.7” x 5.9” x 6.7” (272 x 150 x 170 mm) |
| Drivers | 1x 4” woofer + 2x 2” full-range drivers |
| EQ | Yes |
| Frequency Response | 45Hz - 20kHz |
| IP Rating | IP54 |
| Maximum SPL | 91dB |
| Omnidirectional | No |
| Party Mode | Yes (Auracast) |
| Power Bank | Yes |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | Yes (built-in strap) |
| TWS | Yes |
| Weight | 6.3 lbs (2.85 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Marshall Kilburn III vs Marshall Kilburn II
- Marshall Kilburn III vs JBL Xtreme 4
- Marshall Kilburn III vs Ultimate Ears Everboom
- Marshall Kilburn III vs W-King T9
- Marshall Kilburn III vs Marshall Middleton
- Marshall Kilburn III vs Devialet Mania
- Marshall Kilburn III vs Marshall Middleton II
- Marshall Kilburn III vs Sonos Move 2
- See all 31 comparisons
Sony ULT Field 5: $348.00 Amazon eBay
Older models: the Sony SRS-XB43 (ranked lower, rated 3.5/5) and the Sony SRS-XG300 (ranked lower, rated 3.1/5).
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 | Yes |
| 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 |
| Strap | Yes (detachable shoulder strap) |
| 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 →
- Mateusz Cholewa: SONY ULT Field 5 vs BOGASING S8 PRO MAX More from Mateusz Cholewa →
- Head-to-Head Comparisons