Short answer: the KEF Muo gen2 for sound, the Sony ULT Field 3 for weather sealing. The ULT Field 3 is IP67 rated and dustproof and water resistant, but it sounds a bit hollow and a bit boosted in the treble. The Muo gen2 benefits from KEF’s improved treble and overall balance, though it still lacks deeper bass.
What the KEF Muo gen2 gets right: KEF seemed to have fixed the rolled off treble and overall balance. The catch: Lacking deeper bass.
On the Sony ULT Field 3 side: IP67 rated, dustproof and water resistant. The tradeoff: Sounds a bit hollow, a bit boosted in the treble.
Buy the Sony ULT Field 3. It ranks higher for sound quality than the KEF Muo gen2 and costs less, which settles it without a real tradeoff to make.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| KEF Muo gen2 | Sony ULT Field 3 | |
|---|---|---|
| Price | $249.99 | $138.00 |
| Ranked | #76 of 142 in Medium Size Portable Bluetooth Speakers | #60 of 142 in Medium Size Portable Bluetooth Speakers |
| App | Yes | Yes |
| Battery Life | 24 hours (Manufacturer specified) | 24 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, aptX Adaptive up to 48 kHz 24 bit | SBC, AAC, LDAC |
| IP Rating | IP67 | IP67 |
| Party Mode | Yes (Auracast) | Yes (Party Connect up to 100 speakers) |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Digital Aux Input | Yes (USB-C) | No |
| Weight | 1.6 lbs (740 g) | 2.6 lbs (1.2 kg) |
| Bluetooth Version | 5.4 | 5.2 |
| Drivers | 1x 58x117mm racetrack woofer, 1x 20mm tweeter | 1x 20mm tweeter + 1x 86mm x 46mm woofer |
| Dimensions | 8.5" x 3.2" x 2.3" (216 x 82 x 59 mm) | 10.1" x 4.4" x 3.1" (256 x 113 x 79 mm) |
| Frequency Response | 43Hz - 20kHz (Manufacturer specified) | - |
| Amplifier Power | 40W | 27W |
| Maximum SPL | 90dB (Manufacturer specified) | - |
| Aux Input | No | No |
| EQ | Yes | Yes (App + ULT button) |
| Power Input | USB-C | USB-C |
| Built-in Microphone | - | Yes |
| Power Bank | - | Yes (USB-C, 5V/1.5A) |
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Prices on this page were last checked September 22, 2026 at 5:11 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
KEF Muo gen2: $249.99 Amazon 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 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
Sony ULT Field 3: $138.00 Amazon eBay
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 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 |
| TWS | Yes |
| Weight | 2.6 lbs (1.2 kg) |
- Links
- Reviews, Comparisons and Sound Samples
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