Short answer: the Harman Kardon Onyx Studio 9, since the Altec Lansing Rockbox XL 2.0 has three voicing problems. The Onyx Studio 9 offers Auracast multi-speaker connection alongside classic stereo pairing, with slightly recessed mids, an upper-mids boost, and rolled off upper treble. The Rockbox XL 2.0 is IP67 waterproof and floats upright in water, but its treble is rolled off, its midrange is muddy, and its bass is not very deep.
Buy the Harman Kardon Onyx Studio 9. It is rated higher for sound quality, and the Altec Lansing Rockbox XL 2.0 is discontinued, so it is only available used.
Battery life favors the Altec Lansing Rockbox XL 2.0: rated for 20 hours against 8 hours for the Harman Kardon Onyx Studio 9.
If water resistance matters to you, the Altec Lansing Rockbox XL 2.0 at IP67 (brief submersion) holds up far better than the Harman Kardon Onyx Studio 9 at no water resistance.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
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Specifications Side By Side
| Altec Lansing Rockbox XL 2.0 | Harman Kardon Onyx Studio 9 | |
|---|---|---|
| Price | $160 Discontinued | $184.99 |
| Ranked | #108 of 113 in Boombox Size Portable Bluetooth Speakers | #15 of 113 in Boombox Size Portable Bluetooth Speakers |
| Battery Life | 20 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| Weight | 12.6 lbs (5.71 kg) | 9.3 lbs (4.2 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| App | Yes (Altec Lansing Just Listen app) | Yes (Harman Kardon One app) |
| EQ | Yes (App EQ) | Yes (App EQ) |
| TWS | Yes | Yes |
| Party Mode | Yes (House Party Mode) | Yes (Auracast) |
| Power Bank | Yes (USB-A) | - |
| USB Playback | No | No |
| Built-in Microphone | No | - |
| Power Input | USB-C | AC Power Cable (2-Prong) |
| FM Tuner | No | - |
| IP Rating | IP67 | None |
| Amplifier Power | 120W | 50W RMS |
| Dimensions | 22.2” x 11.2” x 11.6” (564 x 284 x 295 mm) | 11.4” x 11.3” x 5.1” (289.2 x 287.5 x 130 mm) |
| Drivers | 8” woofer + tweeters | 120mm woofer + 3x 20mm tweeters |
| Digital Aux Input | No | No |
| Lights | Yes | - |
| Aux Input | Yes | No |
| Bass Extension (-10dB) | - | 41Hz |
| Maximum SPL | - | 101dB (measured by Alan Ross Reviews) |
| Bluetooth Version | - | 5.3 |
| Strap | - | No |
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