Yeahbox Sonic Boom Ultra vs Zealot S89

Last updated: September 16, 2026

Short answer: the Yeahbox Sonic Boom Ultra for better sound quality, the Zealot S89 for the lower price. The Yeahbox Sonic Boom Ultra ranks #10 of 75 boombox speakers at $349.20. The Zealot S89 ranks #18 at $259.99, $89.21 cheaper.

Yeahbox Sonic Boom Ultra vs Zealot S89

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 Zealot S89 offers: A 7.3kg boombox with a claimed 36Hz bass extension, 40-hour battery life, IPX6 protection, USB-C charging, aux, USB and microSD playback, TWS and multi-speaker PartyAdd. Listener comparisons find it capable of very high output and substantial bass for outdoor use. Watch for: At high volume, listener reports describe the bass as loose or muddy and the overall balance as less clear than better boombox speakers. The heavy cabinet and basic finish also make it less polished for daily portability, while its multiple EQ modes cannot substitute for a genuinely neutral tuning.

Buy the Yeahbox Sonic Boom Ultra when sound quality outweighs the price for you, and the Zealot S89 when the price outweighs sound quality instead.

Still deciding? The full Portable Bluetooth rankings cover every ranked option.

Buy the Yeahbox Sonic Boom Ultra at Amazon ($349.20) →Buy the Zealot S89 at Amazon ($259.99) →

Specifications Side By Side

Yeahbox Sonic Boom Ultra Zealot S89
Price$349.20$259.99
Ranked#10 of 75 in Boombox Size Portable Bluetooth Speakers#18 of 75 in Boombox Size Portable Bluetooth Speakers
AppYesNo
Aux InputYesYes
Battery Capacity45000mAh (Reviewer estimated)-
Bluetooth Version6.0-
Dimensions23.4" x 9.8" x 12.3" (595 x 248 x 313 mm)21.2" x 10.4" x 9.4" (538 x 265 x 240 mm)
Drivers6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way130W subwoofer + 2x 40mm drivers + 2x tweeters
EQYes (Country, Classic, and custom app EQ; custom settings don't persist after the app closes)Yes (multiple modes)
InputsHDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic-
IP RatingIPX6IPX6
MicroSD PlaybackYesYes
Amplifier Power320W RMS / 500W Peak250W
Party ModeNo (TWS stereo pairing of 2 units only, no Auracast)Yes (PartyAdd up to 100 speakers)
Power InputUSB-C (60W fast charging)USB-C
StereoYesYes
OmnidirectionalNoNo
TWSYesYes
USB PlaybackYesYes
Weight24.3 lbs (11 kg)16.1 lbs (7.3 kg)
Digital Aux InputNoNo
Bluetooth CodecsSBC (inferred; additional codecs unverified)SBC
LightsYes-
Bass Extension (-10dB)-36Hz
Battery Life-40 hours (Manufacturer specified)
Power Bank-Yes (USB-A + USB-C)
Built-in Microphone-No
Buy the Yeahbox Sonic Boom Ultra at Amazon ($349.20) →Buy the Zealot S89 at Amazon ($259.99) →

More worthwhile head-to-heads for 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

Yeahbox Sonic Boom Ultra ranking card

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 Power320W RMS / 500W Peak
AppYes
Aux InputYes
Battery Capacity45000mAh (Reviewer estimated)
Bluetooth CodecsSBC (inferred; additional codecs unverified)
Bluetooth Version6.0
Digital Aux InputNo
Dimensions23.4" x 9.8" x 12.3" (595 x 248 x 313 mm)
Drivers6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way
EQYes (Country, Classic, and custom app EQ; custom settings don't persist after the app closes)
IP RatingIPX6
InputsHDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic
LightsYes
MicroSD PlaybackYes
OmnidirectionalNo
Party ModeNo (TWS stereo pairing of 2 units only, no Auracast)
Power InputUSB-C (60W fast charging)
StereoYes
TWSYes
USB PlaybackYes
Weight24.3 lbs (11 kg)
Check current price at Amazon ($349.20) →Search eBay for Yeahbox Sonic Boom Ultra →

Zealot S89: $259.99 Amazon Aliexpress eBay

Zealot S89 ranking card

Pros: A 7.3kg boombox with a claimed 36Hz bass extension, 40-hour battery life, IPX6 protection, USB-C charging, aux, USB and microSD playback, TWS and multi-speaker PartyAdd. Listener comparisons find it capable of very high output and substantial bass for outdoor use. Measured bass extension of 36Hz (-10dB).

Cons: At high volume, listener reports describe the bass as loose or muddy and the overall balance as less clear than better boombox speakers. The heavy cabinet and basic finish also make it less polished for daily portability, while its multiple EQ modes cannot substitute for a genuinely neutral tuning.

Full Zealot S89 review and specifications →

Amplifier Power250W
AppNo
Aux InputYes
Bass Extension (-10dB)36Hz
Battery Life40 hours (Manufacturer specified)
Bluetooth CodecsSBC
Built-in MicrophoneNo
Digital Aux InputNo
Dimensions21.2" x 10.4" x 9.4" (538 x 265 x 240 mm)
Drivers130W subwoofer + 2x 40mm drivers + 2x tweeters
EQYes (multiple modes)
IP RatingIPX6
MicroSD PlaybackYes
OmnidirectionalNo
Party ModeYes (PartyAdd up to 100 speakers)
Power BankYes (USB-A + USB-C)
Power InputUSB-C
StereoYes
TWSYes
USB PlaybackYes
Weight16.1 lbs (7.3 kg)
Check current price at Amazon ($259.99) →Check current price at Aliexpress ($193.58) →Search eBay for Zealot S89 →