Yeahbox Sonic Boom Ultra vs Harman Kardon Onyx Studio 6

Last updated: September 16, 2026

Short answer: the Yeahbox Sonic Boom Ultra for better sound quality, the Harman Kardon Onyx Studio 6 for the lower price. The Yeahbox Sonic Boom Ultra ranks #10 of 75 boombox speakers at $349.20. The Harman Kardon Onyx Studio 6 ranks #12 at $130, $219.20 cheaper.

Yeahbox Sonic Boom Ultra vs Harman Kardon Onyx Studio 6

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 Harman Kardon Onyx Studio 6 offers: Harman Kardon Onyx Studio 6 uses 2x 75mm woofers + 2x 20mm tweeters. Its 2.94 kg, claimed 8 hours (Manufacturer specified) battery life, IPX7 protection, aux input, up to 96dB and stereo playback make it a practical option for its intended room or portable use. Watch for: Bass is limited by its 37Hz specification. There is no companion app. No EQ adjustment.

Buy the Yeahbox Sonic Boom Ultra if sound quality is the priority over the price, or the Harman Kardon Onyx Studio 6 if the price is the priority over sound quality.

Want more options? Browse the full Portable Bluetooth rankings.

Buy the Yeahbox Sonic Boom Ultra at Amazon ($349.20) →Buy the Harman Kardon Onyx Studio 6 at Amazon ($130) →

Specifications Side By Side

Yeahbox Sonic Boom Ultra Harman Kardon Onyx Studio 6
Price$349.20$130
Ranked#10 of 75 in Boombox Size Portable Bluetooth Speakers#12 of 75 in Boombox Size Portable Bluetooth Speakers
AppYesNo
Aux InputYesYes
Battery Capacity45000mAh (Reviewer estimated)-
Bluetooth Version6.04.2
Dimensions23.4" x 9.8" x 12.3" (595 x 248 x 313 mm)5" x 11.5" x 11.2" (128 x 291 x 284 mm)
Drivers6x9in racetrack woofer (200W) + 2x 4.5in midrange (40W each) + 2x tweeters (20W each), true 3-way2x 75mm woofers + 2x 20mm tweeters
EQYes (Country, Classic, and custom app EQ; custom settings don't persist after the app closes)No
InputsHDMI ARC (in/out, usable as a TV soundbar), AUX in/out, USB drive, microSD, optional wired mic-
IP RatingIPX6IPX7
MicroSD PlaybackYes-
Amplifier Power320W RMS / 500W Peak50W RMS
Party ModeNo (TWS stereo pairing of 2 units only, no Auracast)Yes (Wireless Dual Sound)
Power InputUSB-C (60W fast charging)DC Barrel Connector (19V/2A)
StereoYesYes
OmnidirectionalNoNo
TWSYesYes (see https://www.reddit.com/r/Bluetooth_Speakers/comments/w339x5/how_to_harman_kardon_onyx_studio_5_6_dual_sound/)
USB PlaybackYesNo
Weight24.3 lbs (11 kg)6.5 lbs (2.94 kg)
Digital Aux InputNoNo
Bluetooth CodecsSBC (inferred; additional codecs unverified)SBC
LightsYes-
Bass Extension (-10dB)-37Hz
Battery Life-8 hours (Manufacturer specified)
Built-in Microphone-Yes
Bluetooth Latency-180ms
Maximum SPL-96dB (measured by Alan Ross Reviews)
Power Bank-No
Buy the Yeahbox Sonic Boom Ultra at Amazon ($349.20) →Buy the Harman Kardon Onyx Studio 6 at Amazon ($130) →

How Yeahbox Sonic Boom Ultra compares with other leading options:

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 →

Harman Kardon Onyx Studio 6: $130 Amazon eBay

Harman Kardon Onyx Studio 6 ranking card

Pros: Harman Kardon Onyx Studio 6 uses 2x 75mm woofers + 2x 20mm tweeters. Its 2.94 kg, claimed 8 hours (Manufacturer specified) battery life, IPX7 protection, aux input, up to 96dB and stereo playback make it a practical option for its intended room or portable use. Measured bass extension of 37Hz (-10dB).

Cons: Bass is limited by its 37Hz specification. There is no companion app. No EQ adjustment.

Full Harman Kardon Onyx Studio 6 review and specifications →

Amplifier Power50W RMS
AppNo
Aux InputYes
Bass Extension (-10dB)37Hz
Battery Life8 hours (Manufacturer specified)
Bluetooth CodecsSBC
Bluetooth Latency180ms
Bluetooth Version4.2
Built-in MicrophoneYes
Digital Aux InputNo
Dimensions5" x 11.5" x 11.2" (128 x 291 x 284 mm)
Drivers2x 75mm woofers + 2x 20mm tweeters
EQNo
IP RatingIPX7
Maximum SPL96dB (measured by Alan Ross Reviews)
OmnidirectionalNo
Party ModeYes (Wireless Dual Sound)
Power BankNo
Power InputDC Barrel Connector (19V/2A)
StereoYes
TWSYes (see https://www.reddit.com/r/Bluetooth_Speakers/comments/w339x5/how_to_harman_kardon_onyx_studio_5_6_dual_sound/)
USB PlaybackNo
Weight6.5 lbs (2.94 kg)
Check current price at Amazon ($130) →Search eBay for Harman Kardon Onyx Studio 6 →