Short answer: the Tronsmart Mirtune S100. Both are rated 3.1/5 for sound quality (#97 and #99 of 179 medium speakers), and the Tronsmart Mirtune S100 costs $79.99 against $138 for the Sony ULT Field 1, and with sound quality even, the cheaper one is the better buy.
The Tronsmart Mirtune S100 is the longer-running choice. A waterproof speaker with long battery life for outdoor and casual listening. It is rated for 20 hours of battery against 12 for the Sony ULT Field 1. It keeps a wired aux input, which the Sony ULT Field 1 lacks.
The Sony ULT Field 1 is the lighter option. A tough, waterproof small speaker that survives drops, with long real world battery life and stereo pairing. At 1.4 lbs (650 g) it weighs much less than the Tronsmart Mirtune S100 at 3 lbs (1.36 kg). It supports AAC Bluetooth, which the Tronsmart Mirtune S100 lacks. Watch for: Upper midrange peak, rolled off treble.
Buy the Tronsmart Mirtune S100. Both are rated the same for sound quality, and it costs $58.01 less than the Sony ULT Field 1.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Prices on this page were last checked November 7, 2026 at 7:34 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.
As an eBay Partner, we may be compensated if you make a purchase.
Specifications Side By Side
| Tronsmart Mirtune S100 | Sony ULT Field 1 | |
|---|---|---|
| Price | $79.99 | $138.00 |
| Ranked | #97 of 179 in Medium Size Portable Bluetooth Speakers | #99 of 179 in Medium Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | ~64Hz | - |
| Battery Life | 20 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| Built-in Microphone | Yes | Yes |
| IP Rating | IPX7 | IP67 |
| Stereo | Partially | No |
| Omnidirectional | No | No |
| Weight | 3 lbs (1.36 kg) | 1.4 lbs (650 g) |
| Wi-Fi | No | - |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 5.3 | 5.3 |
| Dimensions | 9.1” x 3.5” x 3.9” (231 x 88 x 100 mm) | 8.1” x 3” x 3” (206 x 77 x 76 mm) |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) | - |
| Amplifier Power | 50W | - |
| Drivers | 20W drivers | 83mm x 42mm woofer, 16mm tweeter + passive radiator |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC | AAC, SBC |
| App | Yes | Yes |
| Aux Input | Yes | No |
| EQ | Yes | Yes |
| TWS | Yes | Yes |
| Power Input | USB-C | USB-C |
| Party Mode | - | Yes (Party Connect up to 100 speakers) |
| Power Bank | - | No |
| Strap | - | Yes (detachable strap) |
Related Speaker Comparisons
How Tronsmart Mirtune S100 compares with other leading options: