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 Sony ULT Field 1 ranks #99, rated 3.1/5, and costs $138, so there is not much of a tradeoff to weigh.
The case for the Tronsmart Mirtune C3 Plus: An affordable waterproof speaker with a separate tweeter, app EQ, Auracast linking, stereo pairing and USB-C audio input. Watch for: 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 case for the Sony ULT Field 1: A tough, waterproof small speaker that survives drops, with long real world battery life and stereo pairing. It supports AAC Bluetooth, which the Tronsmart Mirtune C3 Plus lacks. The tradeoff: Upper midrange peak, rolled off treble.
Buy the Tronsmart Mirtune C3 Plus. It is rated higher for sound quality than the Sony ULT Field 1 and costs less, so it is the default pick unless a specific strength of the other one matters more to you.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
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 | Sony ULT Field 1 | |
|---|---|---|
| Price | $49.99 | $138.00 |
| Ranked | #84 of 182 in Medium Size Portable Bluetooth Speakers | #99 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) | 12 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | AAC, SBC |
| Bluetooth Version | 6.0 | 5.3 |
| 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) | 8.1” x 3” x 3” (206 x 77 x 76 mm) |
| Drivers | 1x racetrack woofer + 1x tweeter | 83mm x 42mm woofer, 16mm tweeter + passive radiator |
| EQ | Yes (app) | Yes |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) | - |
| IP Rating | IPX7 | IP67 |
| Omnidirectional | No | No |
| Party Mode | Yes (Auracast) | Yes (Party Connect up to 100 speakers) |
| Power Input | USB-C | USB-C |
| Stereo | No | No |
| Strap | Yes (lanyard) | Yes (detachable strap) |
| TWS | Yes | Yes |
| Weight | 1.8 lbs (0.81 kg) | 1.4 lbs (650 g) |
| Built-in Microphone | - | Yes |
| Power Bank | - | No |
Where the Ratings Come From
- Tronsmart Mirtune C3 Plus: reviews by Oluv, Mateusz Cholewa and Techder Audios.
- Sony ULT Field 1: reviews by Techder Audios, Jay’s Straight Up Reviews & More and Storytripper HD.
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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