Short answer: the Sony ULT Field 1, if you are buying new. The Bogasing M4 ranks higher than it (#28 vs #97 of 164 medium speakers, 4.0/5 vs 3.1/5) but is discontinued, so only consider it used; the Sony ULT Field 1 is still sold new at $138.
The Bogasing M4 is the better-sounding, longer-running pick. Super Bass mode gives the most balanced sound. It is rated for 24 hours of battery against 12 for the Sony ULT Field 1. It keeps a wired aux input, which the Sony ULT Field 1 lacks. It plays in stereo from a single unit, unlike the Sony ULT Field 1. The catch: It sounds a bit harsh and thin.
What the Sony ULT Field 1 does well: IP67 rated, survives drops and 1m submersion. It has an adjustable EQ, which the Bogasing M4 lacks. The tradeoff: Upper midrange peak, rolled off treble.
Buy the Sony ULT Field 1 if you want one new; the Bogasing M4 is discontinued, so only look for it used.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Bogasing M4 | Sony ULT Field 1 | |
|---|---|---|
| Price | $45.99 Discontinued | $138.00 |
| Ranked | #28 of 164 in Medium Size Portable Bluetooth Speakers | #97 of 164 in Medium Size Portable Bluetooth Speakers |
| App | No | Yes |
| Aux Input | Yes | No |
| Bass Extension (-10dB) | 54Hz | - |
| Battery Life | 24 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| EQ | No | Yes |
| IP Rating | IPX7 | IP67 |
| Bluetooth Latency | 150ms | - |
| Maximum SPL | 99dB (measured by Alan Ross Reviews) | - |
| MicroSD Playback | Yes | - |
| Power Input | USB-C | USB-C |
| Stereo | Yes | No |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 1.6 lbs (731 g) | 1.4 lbs (650 g) |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 5.0 | 5.3 |
| Amplifier Power | 40W | - |
| Drivers | 52mm speaker unit | 83mm x 42mm woofer, 16mm tweeter + passive radiator |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) | AAC, SBC |
| Dimensions | 3.1”H x 8.4”W x 2.5”D (80 x 214 x 63 mm) | 8.1” x 3” x 3” (206 x 77 x 76 mm) |
| Built-in Microphone | - | Yes |
| Party Mode | - | Yes (Party Connect up to 100 speakers) |
| Power Bank | - | No |
| Strap | - | Yes (detachable strap) |
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Prices on this page were last checked October 4, 2026 at 9:58 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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The Two Speakers In Full
Bogasing M4: $45.99 Discontinued eBay
Newer model: the Bogasing M5, ranked lower, rated 3.5/5.
Pros: Bogasing M4 uses 52mm speaker unit. Its 731 g, claimed 24 hours (Manufacturer specified) battery life, IPX7 protection, aux input, up to 99dB and stereo playback make it a practical option for its intended room or portable use. Super Bass mode gives the most balanced sound. Measured bass extension of 54Hz (-10dB).
Cons: Bass is limited by its 54Hz specification. There is no companion app. No EQ adjustment. It sounds a bit harsh and thin. Discontinued.
Full Bogasing M4 review and specifications →
| Amplifier Power | 40W |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | 54Hz |
| Battery Life | 24 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) |
| Bluetooth Latency | 150ms |
| Bluetooth Version | 5.0 |
| Digital Aux Input | No |
| Dimensions | 3.1”H x 8.4”W x 2.5”D (80 x 214 x 63 mm) |
| Drivers | 52mm speaker unit |
| EQ | No |
| IP Rating | IPX7 |
| Maximum SPL | 99dB (measured by Alan Ross Reviews) |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 1.6 lbs (731 g) |
- Reviews, Comparisons and Sound Samples
- Alan Ross Reviews: Bogasing M4 Review - vs JBL Charge 5 & Motion Plus - a new contender? More from alanrossreviews →
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- Alan Ross Reviews: Bogasing M4 or Soundcore Boost or Maxsound Plus for $50 champion?? 🤷♀️
- Alan Ross Reviews: Tronsmart Element Force review vs Bogasing M4 - cheap speaker 🤑
- Head-to-Head Comparisons
Sony ULT Field 1: $138.00 Amazon eBay
Older models: the Sony XB23 (ranked higher, rated 3.3/5) and the Sony SRS-XB20 (ranked lower, rated 2.8/5).
Larger models: the Sony ULT Field 7 (rated 3.2/5) and the Sony ULT Tower 10 (rated 3.9/5).
Pros: IP67 rated, survives drops and 1m submersion. Real-world battery around 28+ hours with ULT (bass boost) mode off. Stereo-pairs with a second ULT Field 1.
Cons: Upper midrange peak, rolled off treble
Full Sony ULT Field 1 review and specifications →
| App | Yes |
|---|---|
| Aux Input | No |
| Battery Life | 12 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | AAC, SBC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 8.1” x 3” x 3” (206 x 77 x 76 mm) |
| Drivers | 83mm x 42mm woofer, 16mm tweeter + passive radiator |
| EQ | Yes |
| IP Rating | IP67 |
| Omnidirectional | No |
| Party Mode | Yes (Party Connect up to 100 speakers) |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | No |
| Strap | Yes (detachable strap) |
| TWS | Yes |
| Weight | 1.4 lbs (650 g) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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