Short answer: the Yeahbox Sonic Boom Ultra. It ranks #10 of 75 boombox speakers by sound quality at $349.20; the Diamondboxx M3 ranks #53 and costs $700, so there is not much of a tradeoff to weigh.
What the Yeahbox Sonic Boom Ultra offers: By far the loudest boombox tested against it, hitting 106-107dB, roughly 3-5dB louder than the JBL Boombox 4, Zealot ZE41, Tribit Stormbox Blast 2, W-King X20, and Hopestar A90/A95. The massive 6x9in racetrack woofer reaches audible bass down to around 30Hz on the Country EQ preset, and a teardown confirmed genuinely robust internals: a thick vented voice coil and a dedicated crossover output per driver. HDMI ARC input/output lets it double as a TV soundbar, a feature none of its direct competitors offer. Watch for: 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 custom EQ in the app noticeably reduces bass output compared to the factory presets and doesn’t persist after the speaker powers off. No Auracast, no removable battery, a plastic handle with some flex, and heavy at 11kg (24lb) for $388. Most of the sound-quality coverage comes from enthusiast listening-test comparisons rather than independent measurement.
What the Diamondboxx M3 offers: An unusually compact 5kg high-output boombox, with a claimed 200W RMS Class A/B amplifier, 114dB maximum level, active crossovers and a choice of large battery packs. It has aux input, USB-C power and TWS pairing, while the aluminum heat sink is designed to sustain loud playback without thermal shutdown. Watch for: Despite its output, bass does not reach as deep as the best large portables and can distort when pushed hard. The treble-forward tuning can sound aggressive, there is no app or EQ to correct it, and the lack of a water rating makes it a poor match for poolside or rough-weather use.
Buy the Yeahbox Sonic Boom Ultra. It ranks higher for sound quality than the Diamondboxx M3 and costs less, which settles it without a real tradeoff to make.
Water resistance is not close: the Yeahbox Sonic Boom Ultra is rated at IPX6 (powerful water jets), well ahead of the Diamondboxx M3 at no water resistance.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Yeahbox Sonic Boom Ultra | Diamondboxx M3 | |
|---|---|---|
| Price | $349.20 | $700 |
| Ranked | #10 of 75 in Boombox Size Portable Bluetooth Speakers | #53 of 75 in Boombox Size Portable Bluetooth Speakers |
| App | Yes | No |
| Aux Input | Yes | Yes |
| Battery Capacity | 45000mAh (Reviewer estimated) | - |
| Bluetooth Version | 6.0 | - |
| 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 | - | 40 hours (Manufacturer specified) |
| Power Bank | - | No |
| Built-in Microphone | - | No |
| FM Tuner | - | No |
Related Speaker Comparisons
How Yeahbox Sonic Boom Ultra compares with other leading options:
- Yeahbox Sonic Boom Ultra vs Tribit Stormbox Blast
- JBL Partybox Encore 2 vs Yeahbox Sonic Boom Ultra
- JBL Partybox Encore Essential 2 vs Yeahbox Sonic Boom Ultra
- Yeahbox Sonic Boom Ultra vs JBL Partybox Encore
- JBL Partybox Encore Essential vs Yeahbox Sonic Boom Ultra
Prices on this page were last checked September 16, 2026 at 12:41 AM 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
Yeahbox Sonic Boom Ultra: $349.20 Amazon eBay
Pros: By far the loudest boombox tested against it, hitting 106-107dB, roughly 3-5dB louder than the JBL Boombox 4, Zealot ZE41, Tribit Stormbox Blast 2, W-King X20, and Hopestar A90/A95. The massive 6x9in racetrack woofer reaches audible bass down to around 30Hz on the Country EQ preset, and a teardown confirmed genuinely robust internals: a thick vented voice coil and a dedicated crossover output per driver. HDMI ARC input/output lets it double as a TV soundbar, a feature none of its direct competitors offer.
Cons: 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 custom EQ in the app noticeably reduces bass output compared to the factory presets and doesn’t persist after the speaker powers off. No Auracast, no removable battery, a plastic handle with some flex, and heavy at 11kg (24lb) for $388. Most of the sound-quality coverage comes from enthusiast listening-test comparisons rather than independent measurement.
Full Yeahbox Sonic Boom Ultra review and specifications →
| Amplifier Power | 320W RMS / 500W Peak |
|---|---|
| App | Yes |
| Aux Input | Yes |
| Battery Capacity | 45000mAh (Reviewer estimated) |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) |
| Bluetooth Version | 6.0 |
| Digital Aux Input | No |
| Dimensions | 23.4" x 9.8" x 12.3" (595 x 248 x 313 mm) |
| Drivers | 6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way |
| EQ | Yes (Country, Classic, and custom app EQ; custom settings don't persist after the app closes) |
| IP Rating | IPX6 |
| Inputs | HDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic |
| Lights | Yes |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Party Mode | No (TWS stereo pairing of 2 units only, no Auracast) |
| Power Input | USB-C (60W fast charging) |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 24.3 lbs (11 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Jagist reviews: Yeahbox Sonic Boom Ultra Vs Zealot Ze41!!! Battle Of Big Boys!!! 😜😜😜 More from Jagistreviews →
- Jagist reviews: Yeahbox Sonic Boom Ultra Vs Zealot Ze21!!! Battle Of The Deep Bass 🥳🥳🥳
- Jagist reviews: Yeahbox Sonic Boom Ultra Vs W-king X20!!! Old Vs New!!! 🫨🫨🫨
- Techder Audios: YEAHBOX Sonic Boom Ultra VS JBL Boombox 4 "IT BEATS THE KING!?😈😱" More from techderaudios →
- Jagist reviews: Yeahbox Sonic Boom Ultra Vs Tribit Stormbox Blast 2 Firmware 11!!! Holy Crap!!! 🤩🤩🤩
- Jagist reviews: Yeahbox Sonic Boom Ultra Vs Hopestar A95!!! Battle Of Big Boys!!!! 😘😘😘
- Jagist reviews: Yeahbox Sonic Boom Ultra!!! 💥 Unboxing And Review!!! Absolutely A Beast 💯 🥵🥵🥵
- Techder Audios: YEAHBOX Sonic Boom Ultra - Soundtest "DEEP SUBWOOFER LIKE PERFORMANCE!🔥"
- Audio y Mas: El Woofer Más GRANDE en un Altavoz, Yeahbox Sonic Boom Ultra
- Jagist reviews: Yeahbox Sonic Boom Ultra Bass Test!!! What A Beast!!! 😍😍😍
- brett levesque: Yeahbox sonic boom ultra hertz test
- Jagist reviews: Yeahbox Sonic Boom Ultra Hertz Test!!! How Low Will She Go??? 😛😛😛
- Head-to-Head Comparisons
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- Yeahbox Sonic Boom Ultra vs Harman Kardon Onyx Studio 8
- Yeahbox Sonic Boom Ultra vs Harman Kardon Onyx Studio 6
- Yeahbox Sonic Boom Ultra vs JBL Partybox Encore Essential
- Yeahbox Sonic Boom Ultra vs Harman Kardon Onyx Studio 7
- Yeahbox Sonic Boom Ultra vs Harman Kardon Onyx Studio 9
- Yeahbox Sonic Boom Ultra vs JBL Partybox Encore
- Yeahbox Sonic Boom Ultra vs JBL Partybox Encore Essential 2
- See all 44 comparisons
Diamondboxx M3: $700 eBay
Pros: An unusually compact 5kg high-output boombox, with a claimed 200W RMS Class A/B amplifier, 114dB maximum level, active crossovers and a choice of large battery packs. It has aux input, USB-C power and TWS pairing, while the aluminum heat sink is designed to sustain loud playback without thermal shutdown.
Cons: Despite its output, bass does not reach as deep as the best large portables and can distort when pushed hard. The treble-forward tuning can sound aggressive, there is no app or EQ to correct it, and the lack of a water rating makes it a poor match for poolside or rough-weather use.
Full Diamondboxx M3 review and specifications →
| Amplifier Power | 200W RMS / 400W peak |
|---|---|
| App | No |
| Aux Input | Yes |
| Battery Life | 40 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 14.7" x 9" x 8" (373.4 x 228.6 x 203.2 mm) |
| Drivers | 3" woofer + tweeter array |
| EQ | No |
| FM Tuner | No |
| IP Rating | None |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | No |
| Weight | 11 lbs (5 kg) |
- Reviews, Comparisons and Sound Samples
- No independent measurement review is linked for this model; it is ranked from hands-on listening and comparison against similarly priced speakers.
- Head-to-Head Comparisons
- Diamondboxx M3 vs W-King D10
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- See all 44 comparisons