Yeahbox Sonic Boom Ultra vs JBL Authentics 300

Last updated: September 16, 2026

Short answer: the Yeahbox Sonic Boom Ultra. It ranks #10 of 75 boombox speakers by sound quality at $349.20; the JBL Authentics 300 ranks #32 and costs $499.95, which makes this an easy call rather than a real tradeoff.

Yeahbox Sonic Boom Ultra vs JBL Authentics 300

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 JBL Authentics 300 offers: Integrates both Amazon Alexa and Google Assistant simultaneously (rare for smart speakers). Retro seventies design with leather and Quadrex grille. 100-watt amp, carries well with leather-trimmed handle. Rechargeable battery rated ~8 hours. Watch for: Narrow sounding, bass not as deep as others. Peaky upper mids. No TWS. No IP rating. Not as loud as others. Not much battery life.

Buy the Yeahbox Sonic Boom Ultra. It ranks higher for sound quality than the JBL Authentics 300 and costs less, so there is no real case for the other one.

There is a real gap in water resistance: the Yeahbox Sonic Boom Ultra at IPX6 (powerful water jets) against the JBL Authentics 300, which has no water resistance.

Want more options? Browse the full Portable Bluetooth rankings.

Buy the Yeahbox Sonic Boom Ultra at Amazon ($349.20) →Buy the JBL Authentics 300 at Amazon ($499.95) →

Specifications Side By Side

Yeahbox Sonic Boom Ultra JBL Authentics 300
Price$349.20$499.95
Ranked#10 of 75 in Boombox Size Portable Bluetooth Speakers#32 of 75 in Boombox Size Portable Bluetooth Speakers
AppYesYes
Aux InputYesNo
Battery Capacity45000mAh (Reviewer estimated)-
Bluetooth Version6.0-
Dimensions23.4" x 9.8" x 12.3" (595 x 248 x 313 mm)13.5" x 7.7" x 7.1" (342 x 195.6 x 180.3 mm)
Drivers6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way1" tweeter + 4" woofer + passive radiators
EQYes (Country, Classic, and custom app EQ; custom settings don't persist after the app closes)Yes (App EQ)
InputsHDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic-
IP RatingIPX6None
MicroSD PlaybackYesNo
Amplifier Power320W RMS / 500W Peak100W
Party ModeNo (TWS stereo pairing of 2 units only, no Auracast)Yes (Wi-Fi Multi-Room)
Power InputUSB-C (60W fast charging)AC Power cable
StereoYesPartially (1 woofer)
OmnidirectionalNoNo
TWSYesYes
USB PlaybackYesYes
Weight24.3 lbs (11 kg)10.8 lbs (4.9 kg)
Digital Aux InputNoNo
Bluetooth CodecsSBC (inferred; additional codecs unverified)SBC
LightsYes-
Bass Extension (-10dB)-45Hz
Battery Life-8 hours (Manufacturer specified)
Maximum SPL-100dB (measured by Alan Ross Reviews)
Wi-Fi-Yes
Power Bank-No
Built-in Microphone-Yes
Buy the Yeahbox Sonic Boom Ultra at Amazon ($349.20) →Buy the JBL Authentics 300 at Amazon ($499.95) →

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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 →

JBL Authentics 300: $499.95 Amazon eBay

JBL Authentics 300 ranking card

Pros: Integrates both Amazon Alexa and Google Assistant simultaneously (rare for smart speakers). Retro seventies design with leather and Quadrex grille. 100-watt amp, carries well with leather-trimmed handle. Rechargeable battery rated ~8 hours. Measured bass extension of 45Hz (-10dB).

Cons: Narrow sounding, bass not as deep as others. Peaky upper mids. No TWS. No IP rating. Not as loud as others. Not much battery life.

Full JBL Authentics 300 review and specifications →

Amplifier Power100W
AppYes
Aux InputNo
Bass Extension (-10dB)45Hz
Battery Life8 hours (Manufacturer specified)
Bluetooth CodecsSBC
Built-in MicrophoneYes
Digital Aux InputNo
Dimensions13.5" x 7.7" x 7.1" (342 x 195.6 x 180.3 mm)
Drivers1" tweeter + 4" woofer + passive radiators
EQYes (App EQ)
IP RatingNone
Maximum SPL100dB (measured by Alan Ross Reviews)
MicroSD PlaybackNo
OmnidirectionalNo
Party ModeYes (Wi-Fi Multi-Room)
Power BankNo
Power InputAC Power cable
StereoPartially (1 woofer)
TWSYes
USB PlaybackYes
Weight10.8 lbs (4.9 kg)
Wi-FiYes
Check current price at Amazon ($499.95) →Search eBay for JBL Authentics 300 →