Short answer: the Harman Kardon Onyx Studio 9. It ranks #13 of 73 boombox speakers by sound quality at $186.99; the W-King X20 ranks #28 and costs $219.98, so there is not much of a tradeoff to weigh.
What the Harman Kardon Onyx Studio 9 offers: Auracast multi-speaker connection alongside classic stereo pairing. Harman Kardon One app with EQ. USB-C charging, up from the previous generation’s AC power brick. Watch for: Slight recessed mids, boost in the upper mids, rolled off upper treble. Not as deep bass as previous Onyx Studio speakers.
What the W-King X20 offers: 200W RMS output with 330W peak power, 112dB max volume, exceptional 24-hour battery life with power bank, IPX6 waterproof, EQ with app control and button modes, 7.5-inch subwoofer, Bluetooth 5.3, dual pairing, MicroSD and USB playback, AUX input, TWS stereo mode with 240W combined Watch for: Rising frequency response but upper treble rolled off, 700hz and 1.2khz peaks
Buy the Harman Kardon Onyx Studio 9. It ranks higher for sound quality than the W-King X20 and costs less, so there is no real case for the other one.
If water resistance matters to you, the W-King X20 at IPX6 (powerful water jets) holds up far better than the Harman Kardon Onyx Studio 9 at no water resistance.
Specifications Side By Side
| Harman Kardon Onyx Studio 9 | W-King X20 | |
|---|---|---|
| Price | $186.99 | $219.98 after coupon |
| Ranked | #13 of 73 in Boombox Size Portable Bluetooth Speakers | #28 of 73 in Boombox Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | 41Hz | ~42Hz |
| Max Volume | 101dB | 112dB |
| 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 | 15.9 lbs / 7200 g |
| App | Yes (Harman Kardon One app) | Yes (W-King app) |
| Bluetooth Codecs | SBC | SBC |
| EQ | Yes (App EQ) | Yes (App + button modes) |
| Party Mode | Yes (Auracast) | No |
| USB Playback | No | Yes |
| Bluetooth Version | 5.3 | - |
| Battery Life | 8 hours (Manufacturer specified) | - |
| Output Power | 50W RMS | 330W peak / 200W RMS |
| Dimensions | 11.4" x 11.3" x 5.1" (289.2 x 287.5 x 130 mm) | 19.9" x 8.5" x 10.6" (506 x 217 x 270 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters | 7.5" subwoofer + drivers |
| Digital Aux Input | No | No |
| Aux Input | - | Yes |
| MicroSD Playback | - | Yes |
| Power Bank | - | Yes (USB-A) |
| Built in Microphone | - | No |
Related Speaker Comparisons
A few more comparisons worth a look in the same class:
- W-King D20 vs W-King H10
- W-King D20 vs Yeahbox Sonic Boom Max 3
- Harman Kardon Onyx Studio 7 vs W-King D10
- Harman Kardon Onyx Studio 9 vs W-King H10
- W-King D20 vs W-King X20
Prices on this page were last checked August 27, 2026 at 10:09 PM 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
Harman Kardon Onyx Studio 9: $186.99 Amazon eBay
Pros: Auracast multi-speaker connection alongside classic stereo pairing. Harman Kardon One app with EQ. USB-C charging, up from the previous generation’s AC power brick.
Cons: Slight recessed mids, boost in the upper mids, rolled off upper treble. Not as deep bass as previous Onyx Studio speakers.
Full Harman Kardon Onyx Studio 9 review and specifications →
| App | Yes (Harman Kardon One app) |
|---|---|
| Bass Extension (-10dB) | 41Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Digital Aux Input | No |
| Dimensions | 11.4" x 11.3" x 5.1" (289.2 x 287.5 x 130 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters |
| EQ | Yes (App EQ) |
| IP Rating | None |
| Max Volume | 101dB |
| Omnidirectional | No |
| Output Power | 50W RMS |
| Party Mode | Yes (Auracast) |
| Power Input | AC Power Cable (2-Prong) |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | No |
| Weight | 9.3 lbs / 4.2 kg |
- Links
- Reviews, Comparisons and Sound Samples
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W-King X20: $219.98 after coupon Amazon eBay
Pros: 200W RMS output with 330W peak power, 112dB max volume, exceptional 24-hour battery life with power bank, IPX6 waterproof, EQ with app control and button modes, 7.5-inch subwoofer, Bluetooth 5.3, dual pairing, MicroSD and USB playback, AUX input, TWS stereo mode with 240W combined
Cons: Rising frequency response but upper treble rolled off, 700hz and 1.2khz peaks
Full W-King X20 review and specifications →
| App | Yes (W-King app) |
|---|---|
| Aux Input | Yes |
| Bass Extension (-10dB) | ~42Hz |
| Bluetooth Codecs | SBC |
| Built in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 19.9" x 8.5" x 10.6" (506 x 217 x 270 mm) |
| Drivers | 7.5" subwoofer + drivers |
| EQ | Yes (App + button modes) |
| IP Rating | IPX6 |
| Max Volume | 112dB |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Output Power | 330W peak / 200W RMS |
| Party Mode | No |
| Power Bank | Yes (USB-A) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 15.9 lbs / 7200 g |
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