Short answer: the Yeahbox Sonic Boom Ultra. It ranks #11 of 112 boombox speakers by sound quality, rated 4.2/5, at $388. The Zealot S78 ranks #110, rated 2.0/5, at $91.38, $296.62 cheaper, which does not close the gap in sound quality.
The Yeahbox Sonic Boom Ultra is the better-sounding choice. A massively loud boombox with deep bass, long battery life, and HDMI ARC so it can double as a TV soundbar. 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 Zealot S78 is the longer-running, lighter choice. A loud, rugged party speaker with full waterproofing, a power bank and wireless pairing for outdoor parties. It is rated for 40 hours of battery against 24 for the Yeahbox Sonic Boom Ultra. At 9.7 lbs (4.4 kg) it weighs much less than the Yeahbox Sonic Boom Ultra at 24.3 lbs (11 kg). The tradeoff: At high volume, reviews report distortion and fluctuating level, so its headline power is more useful below its maximum setting.
Buy the Yeahbox Sonic Boom Ultra. It is rated higher for sound quality, and the $296.62 saving on the Zealot S78 is not enough to make up the difference.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
A massively loud boombox with deep bass, long battery life, and HDMI ARC so it can double as a TV soundbar.
A loud, rugged party speaker with full waterproofing, a power bank and wireless pairing for outdoor parties.
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Specifications Side By Side
| Yeahbox Sonic Boom Ultra | Zealot S78 | |
|---|---|---|
| Price | $388.00 | $91.38 |
| Ranked | #11 of 112 in Boombox Size Portable Bluetooth Speakers | #110 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 | 5.3 |
| Dimensions | 23.4” x 9.8” x 12.3” (595 x 248 x 313 mm) | 16.1” x 6.6” x 7.3” (410 x 167 x 185 mm) |
| Drivers | 6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way | 2x ~120mm (4.72”) woofers + 2x ~42mm tweeters + 2x passive radiators |
| EQ | Yes (Country, Classic, and custom app EQ; custom settings don’t persist after the app closes) | Yes (multiple modes) |
| Inputs | HDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic | - |
| IP Rating | IPX6 | IP67 |
| MicroSD Playback | Yes | Yes |
| Amplifier Power | 320W RMS / 500W Peak | 120W RMS / 150W 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 | Yes |
| Weight | 24.3 lbs (11 kg) | 9.7 lbs (4.4 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 | Yes (detachable shoulder strap) |
| Power Bank | - | Yes (USB-A) |
| Built-in Microphone | - | No |
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