Short answer: the Harman Kardon Onyx Studio 9. It ranks #15 of 113 boombox speakers at $184.99 against the Yeahbox Sonic Boom Max 3’s #59, and it offers Auracast multi-speaker connection alongside classic stereo pairing. Its mids are slightly recessed with a lift in the upper mids and a rolled-off top end; the Yeahbox claims a 200W RMS three-way array, but comes from a budget import brand with limited independent testing.
Buy the Harman Kardon Onyx Studio 9. It is rated higher for sound quality than the Yeahbox Sonic Boom Max 3 and costs less, so it is the default pick unless a specific strength of the other one matters more to you.
Water resistance is not close: the Yeahbox Sonic Boom Max 3 is rated at IPX6 (powerful water jets), well ahead of the Harman Kardon Onyx Studio 9 at no water resistance.
Looking for alternatives? See the complete Portable Bluetooth rankings.
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Specifications Side By Side
| Harman Kardon Onyx Studio 9 | Yeahbox Sonic Boom Max 3 | |
|---|---|---|
| Price | $184.99 | $228.99 |
| Ranked | #15 of 113 in Boombox Size Portable Bluetooth Speakers | #59 of 113 in Boombox Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | 41Hz | - |
| Maximum SPL | 101dB (measured by Alan Ross Reviews) | - |
| IP Rating | None | IPX6 |
| Power Input | AC Power Cable (2-Prong) | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 9.3 lbs (4.2 kg) | 16.8 lbs (7.64 kg) |
| App | Yes (Harman Kardon One app) | Yes |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC (inferred; additional codecs unverified) |
| EQ | Yes (App EQ) | Yes |
| Party Mode | Yes (Auracast) | - |
| USB Playback | No | Yes |
| Bluetooth Version | 5.3 | 5.3 |
| Battery Life | 8 hours (Manufacturer specified) | 111Wh (14.8V/7,500mAh) (Manufacturer specified) |
| Amplifier Power | 50W RMS | 200W RMS / 300W Peak |
| Dimensions | 11.4” x 11.3” x 5.1” (289.2 x 287.5 x 130 mm) | 20.7” x 8.3” x 10.6” (525 x 210 x 268 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters | 189x114mm woofer, 2x 89mm midrange, 2x 38mm tweeters |
| Digital Aux Input | No | No |
| Aux Input | No | Yes |
| Strap | No | No |
| MicroSD Playback | - | Yes |
| Lights | - | Yes |
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