Short answer: the Xiaomi Sound Outdoor, if you are buying new. The EarFun Uboom Slim measures as well as it (#43 vs #46 of 179 medium speakers, 3.7/5 vs 3.7/5) but is discontinued, so only consider it used; the Xiaomi Sound Outdoor is still sold new at $49.99.
The EarFun Uboom Slim is the longer-running choice. A slim, affordable waterproof stereo speaker with long battery life that doubles as a speakerphone. It is rated for 16 hours of battery against 12 for the Xiaomi Sound Outdoor. It keeps a wired aux input, which the Xiaomi Sound Outdoor lacks. It plays in stereo from a single unit, unlike the Xiaomi Sound Outdoor. The catch: Not as deep bass as others.
What the Xiaomi Sound Outdoor does well: An affordable waterproof outdoor speaker with a separate tweeter, decent battery life and linking to many more speakers. The catch: Bass reach is limited for the cabinet size, with a rated lower limit of 60Hz, and the boosted bass gets somewhat uncontrolled at high levels.
Buy the Xiaomi Sound Outdoor, since the EarFun Uboom Slim is discontinued and only worth hunting down used.
Want more options? Browse the full Portable Bluetooth rankings.
Prices on this page were last checked November 11, 2026 at 3:26 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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Specifications Side By Side
| EarFun Uboom Slim | Xiaomi Sound Outdoor | |
|---|---|---|
| Price | $79 Discontinued | $49.99 |
| Ranked | #43 of 179 in Medium Size Portable Bluetooth Speakers | #46 of 179 in Medium Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | ~63Hz | - |
| Battery Life | 16 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| Power Input | USB-C | USB-C |
| Stereo | Yes | No |
| Omnidirectional | No | No |
| Weight | 1.2 lbs (560 g) | 1.3 lbs (597 g) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC (inferred; additional codecs unverified) |
| Bluetooth Version | 5.2 | 5.4 |
| Built-in Microphone | Yes | Yes |
| Drivers | 45mm speaker drivers | 20W woofer, 10W tweeter + 2x passive radiators |
| Amplifier Power | 20W | 30W |
| IP Rating | IPX7 | IP67 |
| Digital Aux Input | No | No |
| Dimensions | 2.6”H x 7.1”W x 2.6”D (65 x 180 x 65 mm) | 7.7” x 2.7” x 2.6” (196.6 x 68 x 66 mm) |
| App | No | No |
| Aux Input | Yes | No |
| EQ | No | No |
| TWS | Yes | Yes |
| Party Mode | - | Yes (Speakersync, up to 100 speakers) |
| Frequency Response | - | 60Hz - 20kHz (Manufacturer specified) |
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