Short answer: the Yeahbox Sonic Boom Ultra. It ranks #11 of 112 boombox speakers by sound quality (rated 4.2/5) at $388 and is still sold new; the Diamondboxx M3 ranks #76 (rated 2.8/5) and is discontinued, so it is only an option used.
The Yeahbox Sonic Boom Ultra is the better-sounding, tougher option. A massively loud boombox with deep bass, long battery life, and HDMI ARC so it can double as a TV soundbar. It is rated IPX6, while the Diamondboxx M3 has no water resistance. It has an adjustable EQ, which the Diamondboxx M3 lacks. The tradeoff: The 500W peak-power rating doesn’t fully hold up: it gets noisy above roughly 80-90% volume, and the midrange isn’t fully refined, sometimes sitting a touch too forward.
The Diamondboxx M3 is the longer-running, lighter option. A compact, very loud boombox with a powerful amplifier and a choice of large battery packs. It is rated for 40 hours of battery against 24 for the Yeahbox Sonic Boom Ultra. At 11 lbs (5 kg) it weighs much less than the Yeahbox Sonic Boom Ultra at 24.3 lbs (11 kg). Watch for: Despite its output, bass does not reach as deep as the best large portables and can distort when pushed hard.
Buy the Yeahbox Sonic Boom Ultra. It is rated higher for sound quality; the Diamondboxx M3 is no longer sold new.
Looking for alternatives? See the complete Portable Bluetooth rankings.
A massively loud boombox with deep bass, long battery life, and HDMI ARC so it can double as a TV soundbar.
A compact, very loud boombox with a powerful amplifier and a choice of large battery packs.
Prices on this page were last checked October 31, 2026 at 7:11 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
| Yeahbox Sonic Boom Ultra | Diamondboxx M3 | |
|---|---|---|
| Price | $388.00 | $700 Discontinued |
| Ranked | #11 of 112 in Boombox Size Portable Bluetooth Speakers | #76 of 112 in Boombox Size Portable Bluetooth Speakers |
| App | Yes | No |
| Aux Input | Yes | Yes |
| Battery Capacity | 45000mAh (Reviewer estimated) | - |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 6.0 | 5.0 |
| Dimensions | 23.4” x 9.8” x 12.3” (595 x 248 x 313 mm) | 14.7” x 9” x 8” (373.4 x 228.6 x 203.2 mm) |
| Drivers | 6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way | 3” woofer + tweeter array |
| EQ | Yes (Country, Classic, and custom app EQ; custom settings don’t persist after the app closes) | No |
| Inputs | HDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic | - |
| IP Rating | IPX6 | None |
| MicroSD Playback | Yes | - |
| Amplifier Power | 320W RMS / 500W Peak | 200W RMS / 400W peak |
| Party Mode | No (TWS stereo pairing of 2 units only, no Auracast) | No |
| Power Input | USB-C (60W fast charging) | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| USB Playback | Yes | No |
| Weight | 24.3 lbs (11 kg) | 11 lbs (5 kg) |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) | SBC |
| Lights | Yes | - |
| Battery Life | 24 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| Strap | No | - |
| Power Bank | - | No |
| Built-in Microphone | - | No |
| FM Tuner | - | No |
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