Short answer: the Sony ULT Field 3. It ranks #68 of 157 medium speakers by sound quality (rated 3.4/5); the Boat Stone 350 ranks #135 (rated 2.3/5).
The Sony ULT Field 3 is the better-sounding, longer-running pick. IP67 rated, dustproof and water resistant. It is rated for 24 hours of battery against 6 for the Boat Stone 350. Watch for: Sounds a bit hollow, a bit boosted in the treble.
The Boat Stone 350 is the lighter pick. 10W cylindrical stereo speaker with dual passive radiators, IPX7 water resistance, microSD card slot, and 3.5mm aux input. At 0.9 lbs (426 g) it weighs much less than the Sony ULT Field 3 at 2.6 lbs (1.2 kg). It keeps a wired aux input, which the Sony ULT Field 3 lacks. The catch: Midrange peaks with rolled-off treble.
Buy the Sony ULT Field 3. It is rated higher for sound quality than the Boat Stone 350.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Specifications Side By Side
| Sony ULT Field 3 | Boat Stone 350 | |
|---|---|---|
| Price | $208.00 | - |
| Ranked | #68 of 157 in Medium Size Portable Bluetooth Speakers | #135 of 157 in Medium Size Portable Bluetooth Speakers |
| App | Yes | No |
| Aux Input | No | Yes |
| Battery Life | 24 hours (Manufacturer specified) | 6 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC, AAC, LDAC | SBC (inferred; additional codecs unverified) |
| Bluetooth Version | 5.2 | 5.0 |
| Built-in Microphone | Yes | Yes |
| Dimensions | 10.1” x 4.4” x 3.1” (256 x 113 x 79 mm) | 3.5” x 7.1” (90 x 180 mm) |
| Drivers | 1x 20mm tweeter + 1x 86mm x 46mm woofer | 2x 20mm tweeters + 2x 45mm drivers |
| EQ | Yes (App + ULT button) | Yes (multiple modes) |
| IP Rating | IP67 | IPX7 |
| Party Mode | Yes (Party Connect up to 100 speakers) | - |
| Power Bank | Yes (USB-C, 5V/1.5A) | - |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 2.6 lbs (1.2 kg) | 0.9 lbs (426 g) |
| Amplifier Power | 27W | 10W |
| Digital Aux Input | No | No |
| Strap | Yes (detachable shoulder strap) | No |
| Bass Extension (-10dB) | - | 87Hz |
| MicroSD Playback | - | Yes |
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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
Sony ULT Field 3: $208.00 Amazon eBay
Older models: the Sony XB33 (ranked lower, rated 3.4/5), the Sony SRS-XE300 (ranked lower, rated 2.8/5) and the Sony SRS-XB30 (ranked lower, rated 2.6/5).
Pros: IP67 rated, dustproof and water resistant. 24 hour battery life. App with 10-band EQ. Party Connect with up to 100 speakers. USB-C in/out for charging your phone.
Cons: Sounds a bit hollow, a bit boosted in the treble. Custom EQ and the ULT bass-boost button can’t be used together: turning on ULT disables the EQ. Bass is very weak with ULT off. Lost to the JBL Charge 6 in a side-by-side comparison despite being the larger speaker.
Full Sony ULT Field 3 review and specifications →
| Amplifier Power | 27W |
|---|---|
| App | Yes |
| Aux Input | No |
| Battery Life | 24 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC, AAC, LDAC |
| Bluetooth Version | 5.2 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 10.1” x 4.4” x 3.1” (256 x 113 x 79 mm) |
| Drivers | 1x 20mm tweeter + 1x 86mm x 46mm 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, 5V/1.5A) |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | Yes (detachable shoulder strap) |
| TWS | Yes |
| Weight | 2.6 lbs (1.2 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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- See all 138 comparisons
Boat Stone 350 eBay
Pros: 10W cylindrical stereo speaker with dual passive radiators, IPX7 water resistance, microSD card slot, and 3.5mm aux input. Measured bass extension of 87Hz (-10dB).
Cons: Midrange peaks with rolled-off treble. Bass extension limited below 87Hz.
Full Boat Stone 350 review and specifications →
| Amplifier Power | 10W |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | 87Hz |
| Battery Life | 6 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) |
| Bluetooth Version | 5.0 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 3.5” x 7.1” (90 x 180 mm) |
| Drivers | 2x 20mm tweeters + 2x 45mm drivers |
| EQ | Yes (multiple modes) |
| IP Rating | IPX7 |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | No |
| TWS | Yes |
| Weight | 0.9 lbs (426 g) |
- Links
- Reviews, Comparisons and Sound Samples
- No independent measurement review is linked for this model; it is ranked from hands-on listening and comparison against similarly priced speakers.
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