Short answer: the Onyx Studio 9 unless the S95 price wins you over. The Zealot S95 is a good value for the boombox class but is a little rolled off up top and not that balanced through the rest of the range. The Onyx Studio 9 adds Auracast multi-speaker connection alongside classic stereo pairing, though it has slightly recessed mids, a boost in the upper mids and rolled off upper treble, and it costs $27.58 more.
Buy the Harman Kardon Onyx Studio 9. It is rated higher for sound quality, and the $27.58 you would save on the Zealot S95 does not close the gap.
There is a real gap in water resistance: the Zealot S95 at IPX6 (powerful water jets) against the Harman Kardon Onyx Studio 9, which has no water resistance.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
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Specifications Side By Side
| Harman Kardon Onyx Studio 9 | Zealot S95 | |
|---|---|---|
| Price | $184.99 | $157.41 |
| Ranked | #15 of 113 in Boombox Size Portable Bluetooth Speakers | #37 of 113 in Boombox Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | 41Hz | 45Hz |
| 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) | 11.3 lbs (5.11 kg) |
| App | Yes (Harman Kardon One app) | No |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| EQ | Yes (App EQ) | Yes (multiple modes) |
| Party Mode | Yes (Auracast) | Yes (PartyAdd up to 100 speakers) |
| USB Playback | No | Yes |
| Bluetooth Version | 5.3 | 5.3 |
| Battery Life | 8 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| Amplifier Power | 50W RMS | 120W |
| Dimensions | 11.4” x 11.3” x 5.1” (289.2 x 287.5 x 130 mm) | 14.1” x 9.6” x 6.6” (358 x 243 x 167 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters | 130W subwoofer + dual drivers |
| Digital Aux Input | No | No |
| Aux Input | No | Yes |
| Strap | No | - |
| MicroSD Playback | - | Yes |
| Power Bank | - | Yes (USB-A, 5V/2A) |
| Built-in Microphone | - | No |
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