Short answer: the Sony ULT Field 3, if you are buying new. The Sony XB33 ranks higher than the KEF Muo gen2 (#77 vs #97 of 175 medium speakers) but is discontinued; its replacement, the Sony ULT Field 3, is rated 3.4/5 at $208 and is still sold new.
Why pick the Sony XB33: IP67 rated and lightweight (2.4 lb). It supports LDAC Bluetooth, which the KEF Muo gen2 lacks. The tradeoff: Not very loud.
The KEF Muo gen2 is the lighter option. KEF seemed to have fixed the rolled off treble and overall balance. At 1.6 lbs (740 g) it weighs noticeably less than the Sony XB33 at 2.4 lbs (1.1 kg). The catch: Lacking deeper bass.
Buy the Sony ULT Field 3, the replacement for the discontinued Sony XB33; it is rated higher for sound quality than the KEF Muo gen2.
Want more options? Browse the full Portable Bluetooth rankings.
Specifications Side By Side
| Sony XB33 | KEF Muo gen2 | |
|---|---|---|
| Price | $110 Discontinued | $249.99 |
| Ranked | #77 of 175 in Medium Size Portable Bluetooth Speakers | #97 of 175 in Medium Size Portable Bluetooth Speakers |
| App | Yes (Sony Music Connect App) | Yes |
| Aux Input | No | No |
| Bass Extension (-10dB) | 50Hz | - |
| Battery Life | 24 hours (Manufacturer specified) | 24 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC, AAC, LDAC | SBC, aptX Adaptive up to 48 kHz 24 bit |
| Bluetooth Latency | 110ms | - |
| EQ | Yes (3 band) | Yes |
| IP Rating | IP67 | IP67 |
| Maximum SPL | 97dB (measured by Alan Ross Reviews) | 90dB (Manufacturer specified) |
| Party Mode | Yes (Party Connect up to 100 speakers) | Yes (Auracast) |
| Power Bank | Yes (USB-A) | - |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| Weight | 2.4 lbs (1.1 kg) | 1.6 lbs (740 g) |
| Bluetooth Version | 5.0 | 5.4 |
| Dimensions | 9.7” x 3.8” x 4.2” (246 x 97 x 106 mm) | 8.5” x 3.2” x 2.3” (216 x 82 x 59 mm) |
| Amplifier Power | 16W RMS | 40W |
| Drivers | 2x 48x70mm X-Balanced racetrack drivers + 2x passive radiators | 1x 58x117mm racetrack woofer, 1x 20mm tweeter |
| Digital Aux Input | No | Yes (USB-C) |
| Lights | Yes | - |
| Power Input | USB-C | USB-C |
| TWS | Yes | Yes |
| Frequency Response | - | 43Hz - 20kHz (Manufacturer specified) |
Related Speaker Comparisons
More worthwhile head-to-heads for Sony XB33:
- Soundcore Motion 300 vs Sony XB33
- Soundcore Motion+ vs Sony XB33
- Soundcore Boost “upgraded” 2021 vs Sony XB33
- JBL Charge 6 vs Sony XB33
- JBL Flip 6 vs Sony XB33
Prices on this page were last checked October 12, 2026 at 4:13 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 XB33: $110 Discontinued eBay
Newer model: the Sony ULT Field 3, ranked higher, rated 3.4/5, released Apr 2025.
Older models: the Sony SRS-XB31 (ranked lower, rated 2.8/5) and the Sony SRS-XB30 (ranked lower, rated 2.6/5). See every Sony XB and ULT generation.
Pros: IP67 rated and lightweight (2.4 lb). App-controlled color LED lighting, Party Connect links up to 100 speakers. ~19 hour real-world battery without lights. Measured bass extension of 50Hz (-10dB).
Cons: Not very loud. Upper bass peaks, midrange dip, upper midrange peaks, not very neutral. Speaker will not remain at max volume and will turn itself down automatically. Discontinued.
Full Sony XB33 review and specifications →
| Released | May 2020 (6 years ago) |
|---|---|
| Amplifier Power | 16W RMS |
| App | Yes (Sony Music Connect App) |
| Aux Input | No |
| Bass Extension (-10dB) | 50Hz |
| Battery Life | 24 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC, AAC, LDAC |
| Bluetooth Latency | 110ms |
| Bluetooth Version | 5.0 |
| Digital Aux Input | No |
| Dimensions | 9.7” x 3.8” x 4.2” (246 x 97 x 106 mm) |
| Drivers | 2x 48x70mm X-Balanced racetrack drivers + 2x passive radiators |
| EQ | Yes (3 band) |
| IP Rating | IP67 |
| Lights | Yes |
| Maximum SPL | 97dB (measured by Alan Ross Reviews) |
| Omnidirectional | No |
| Party Mode | Yes (Party Connect up to 100 speakers) |
| Power Bank | Yes (USB-A) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 2.4 lbs (1.1 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Alan Ross Reviews: Sony XB33 vs XB32 vs JBL Charge 4 best £120 bluetooth speaker? More from alanrossreviews →
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- Alan Ross Reviews: JBL Charge 5 vs Motion Plus and Sony XB33 - ultimate travel speaker 2021 🤗
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- Alan Ross Reviews: Tribit Xsound Mega vs the world! (JBL Charge 5, Bose Flex, Sony XB33, LG PL7) 👍
- GYMCADDY: Sony XE300 Review And Compared to Sony XB33 - A Muffled Mess More from GYMCADDY →
- Head-to-Head Comparisons
KEF Muo gen2: $249.99 Amazon $249.99 eBay
Pros: KEF seemed to have fixed the rolled off treble and overall balance
Cons: Lacking deeper bass. Very thuddy bass. Appears to be the exact same hardware but with updated tuning. Bass distorts as volume increases, and the claimed 43Hz extension is really only audible at low listening volumes, with a few seconds of lag after volume changes. Loses most of its bass off-axis. Customer reviews are mixed, ranging from praise for detail at low volume to complaints of a boxy, hollow sound.
Full KEF Muo gen2 review and specifications →
| Amplifier Power | 40W |
|---|---|
| App | Yes |
| Aux Input | No |
| Battery Life | 24 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC, aptX Adaptive up to 48 kHz 24 bit |
| Bluetooth Version | 5.4 |
| Digital Aux Input | Yes (USB-C) |
| Dimensions | 8.5” x 3.2” x 2.3” (216 x 82 x 59 mm) |
| Drivers | 1x 58x117mm racetrack woofer, 1x 20mm tweeter |
| EQ | Yes |
| Frequency Response | 43Hz - 20kHz (Manufacturer specified) |
| IP Rating | IP67 |
| Maximum SPL | 90dB (Manufacturer specified) |
| Omnidirectional | No |
| Party Mode | Yes (Auracast) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 1.6 lbs (740 g) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons