Short answer: the Tronsmart Mirtune C3 Plus. It ranks #84 of 182 medium speakers by sound quality, rated 3.3/5, at $49.99; the Ultimate Ears Boom 4 ranks #114, rated 2.9/5, and costs $114.99, so there is not much of a tradeoff to weigh.
The Tronsmart Mirtune C3 Plus is the better-sounding choice. An affordable waterproof speaker with a separate tweeter, app EQ, Auracast linking, stereo pairing and USB-C audio input. The tradeoff: In side by side tests by Clinch Audio Bass and Mateusz Cholewa, the Xiaomi Sound Party and Soundcore Boom 3i sounded more refined and fuller, and listeners described the C3 Plus’s treble as dull.
The Ultimate Ears Boom 4 is the lighter option. A tough waterproof speaker that floats, with USB-C charging, app EQ and pairing with other UE speakers. At 1.4 lbs (620 g) it weighs noticeably less than the Tronsmart Mirtune C3 Plus at 1.8 lbs (810 g). It plays in stereo from a single unit, unlike the Tronsmart Mirtune C3 Plus. Watch for: Not much improvement over the old ones.
Buy the Tronsmart Mirtune C3 Plus. It is rated higher for sound quality than the Ultimate Ears Boom 4 and costs less, so only choose the other one for a particular feature it does better.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Prices on this page were last checked November 14, 2026 at 6:17 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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Specifications Side By Side
| Tronsmart Mirtune C3 Plus | Ultimate Ears Boom 4 | |
|---|---|---|
| Price | $49.99 | $114.99 |
| Ranked | #84 of 182 in Medium Size Portable Bluetooth Speakers | #114 of 182 in Medium Size Portable Bluetooth Speakers |
| Aux Input | No | No |
| Amplifier Power | 50W | - |
| App | Yes (Tronsmart) | Yes |
| Battery Life | 12 hours at 50% volume (Manufacturer specified) | 15 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| Bluetooth Version | 6.0 | 5.1 |
| Charging Time | 4 hours | - |
| Digital Aux Input | Yes (USB-C) | No |
| Dimensions | 8.3”H x 3.1”W x 3.3”D (210 x 80 x 85 mm) | 7.2” x 2.9” x 2.9” (184 x 73 x 73 mm) |
| Drivers | 1x racetrack woofer + 1x tweeter | 2x 1.57” (40mm) active drivers + 2x 1.81” x 2.57” (46.1 x 65.2mm) passive radiators |
| EQ | Yes (app) | Yes (via app) |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) | - |
| IP Rating | IPX7 | IP67 |
| Omnidirectional | No | No |
| Party Mode | Yes (Auracast) | - |
| Power Input | USB-C | USB-C |
| Stereo | No | Yes |
| Strap | Yes (lanyard) | Yes (built-in loop) |
| TWS | Yes | Yes |
| Weight | 1.8 lbs (0.81 kg) | 1.4 lbs (620 g) |
| Built-in Microphone | - | No |
| Power Bank | - | No |
| Maximum SPL | - | 85dBC (Manufacturer specified) |
Where the Ratings Come From
- Tronsmart Mirtune C3 Plus: reviews by Oluv, Mateusz Cholewa and Techder Audios.
- Ultimate Ears Boom 4: reviews by Smart Home Sounds and Cameron Dougherty Tech.
This comparison is generated from the ratings, specifications and measurements on each product’s own page, and it updates when that data changes. How we rank explains how each rating is decided.
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