Short answer: the Yeahbox Sonic Boom Ultra. It ranks #11 of 112 boombox speakers by sound quality, rated 4.2/5, at $388. The W-King X20 ranks #43, rated 3.5/5, at $219.98, $168.02 cheaper, not enough of a saving to outweigh the sound-quality gap.
The Yeahbox Sonic Boom Ultra is the better-sounding option. A massively loud boombox with deep bass, long battery life, and HDMI ARC so it can double as a TV soundbar. 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 W-King X20 is the lighter pick. A loud stereo party speaker with a large subwoofer, a 24 hour battery with power bank, and water resistance. At 15.9 lbs (7.2 kg) it weighs noticeably less than the Yeahbox Sonic Boom Ultra at 24.3 lbs (11 kg). Watch for: Rising frequency response but upper treble rolled off, 700Hz and 1.2kHz peaks.
Buy the Yeahbox Sonic Boom Ultra. It is rated higher for sound quality, and the $168.02 saving on the W-King X20 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 stereo party speaker with a large subwoofer, a 24 hour battery with power bank, and water resistance.
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 | W-King X20 | |
|---|---|---|
| Price | $388.00 | $219.98 after coupon |
| Ranked | #11 of 112 in Boombox Size Portable Bluetooth Speakers | #43 of 112 in Boombox Size Portable Bluetooth Speakers |
| App | Yes | Yes (W-King app) |
| Aux Input | Yes | Yes |
| Battery Capacity | 45000mAh (Reviewer estimated) | - |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 6.0 | 5.4 |
| Dimensions | 23.4” x 9.8” x 12.3” (595 x 248 x 313 mm) | 19.9” x 8.5” x 10.6” (506 x 217 x 270 mm) |
| Drivers | 6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way | 7.5” subwoofer + drivers |
| EQ | Yes (Country, Classic, and custom app EQ; custom settings don’t persist after the app closes) | Yes (App + button modes) |
| Inputs | HDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic | - |
| IP Rating | IPX6 | IPX6 |
| MicroSD Playback | Yes | Yes |
| Amplifier Power | 320W RMS / 500W Peak | 330W peak / 200W RMS |
| 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) | 15.9 lbs (7200 g) |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) | SBC |
| Lights | Yes | - |
| Battery Life | 24 hours (Manufacturer specified) | 24 hours (Manufacturer specified) |
| Strap | No | - |
| Bass Extension (-10dB) | - | ~42Hz |
| Maximum SPL | - | 112dB (measured by Alan Ross Reviews) |
| Power Bank | - | Yes (USB-A) |
| Built-in Microphone | - | No |
Watch Them Compared
Videos and reviews that test both speakers side by side.
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