Short answer: the JBL Partybox Encore Essential. Both are rated 4.2/5 for sound quality (#8 and #11 of 112 boombox speakers), and the JBL Partybox Encore Essential costs $299.95 against $388 for the Yeahbox Sonic Boom Ultra, so with nothing between them on sound quality, price settles it.
The JBL Partybox Encore Essential is the lighter option. A compact stereo party speaker with great sound, strong output, and splash resistance for backyard parties. At 13 lbs (5.9 kg) it weighs much less than the Yeahbox Sonic Boom Ultra at 24.3 lbs (11 kg). It links with other speakers (PartyBoost up to 100 speakers), which the Yeahbox Sonic Boom Ultra cannot.
The Yeahbox Sonic Boom Ultra is the longer-running, tougher choice. A massively loud boombox with deep bass, long battery life, and HDMI ARC so it can double as a TV soundbar. It is rated for 24 hours of battery against 6 for the JBL Partybox Encore Essential. It is rated IPX6 against IPX4 for the JBL Partybox Encore Essential. 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.
Buy the JBL Partybox Encore Essential. Both are rated the same for sound quality, and it costs $88.05 less than the Yeahbox Sonic Boom Ultra.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
A compact stereo party speaker with great sound, strong output, and splash resistance for backyard parties.
A massively loud boombox with deep bass, long battery life, and HDMI ARC so it can double as a TV soundbar.
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
| JBL Partybox Encore Essential | Yeahbox Sonic Boom Ultra | |
|---|---|---|
| Price | $299.95 | $388.00 |
| Ranked | #8 of 112 in Boombox Size Portable Bluetooth Speakers | #11 of 112 in Boombox Size Portable Bluetooth Speakers |
| App | Yes (JBL PartyBox app) | Yes |
| Aux Input | Yes | Yes |
| Aux Latency | 17ms | - |
| Bass Extension (-10dB) | 38Hz | - |
| Battery Life | 6 hours (Manufacturer specified) | 24 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC (inferred; additional codecs unverified) |
| Built-in Microphone | No | - |
| EQ | Yes (3 band App EQ) | Yes (Country, Classic, and custom app EQ; custom settings don’t persist after the app closes) |
| IP Rating | IPX4 | IPX6 |
| Bluetooth Latency | 100ms | - |
| Party Mode | Yes (PartyBoost up to 100 speakers) | No (TWS stereo pairing of 2 units only, no Auracast) |
| Power Bank | Yes (USB-A, 5V/0.5A) | - |
| Power Input | AC Power cord | USB-C (60W fast charging) |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| USB Playback | Yes | Yes |
| Weight | 13 lbs (5.9 kg) | 24.3 lbs (11 kg) |
| Bluetooth Version | 5.1 | 6.0 |
| Amplifier Power | 100W RMS | 320W RMS / 500W Peak |
| Dimensions | 10.9” x 12.9” x 11.5” (276 x 327 x 293 mm) | 23.4” x 9.8” x 12.3” (595 x 248 x 313 mm) |
| Drivers | 135mm woofer + 2x 44mm tweeters | 6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way |
| Maximum SPL | 110dB (measured by Alan Ross Reviews) | - |
| Digital Aux Input | No | No |
| Strap | No | No |
| Battery Capacity | - | 45000mAh (Reviewer estimated) |
| Inputs | - | HDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic |
| MicroSD Playback | - | Yes |
| Lights | - | Yes |
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