These are not really the same size class, and that is the honest framing here. The Harman Kardon Onyx Studio 4 ranks #46 of 75 large speakers by sound quality at $100; the Harman Kardon Onyx Studio 9 ranks #13 of 72 boombox speakers by sound quality at $186.99.
On the Harman Kardon Onyx Studio 4 side: Balanced sound quality with deep resonant bass and crisp treble. The tradeoff: 8 hour battery at medium volume.
The case for the Harman Kardon Onyx Studio 9: Auracast multi-speaker connection alongside classic stereo pairing. The catch: Slight recessed mids, boost in the upper mids, rolled off upper treble.
Buy the Harman Kardon Onyx Studio 4 at $100 if you want a large speaker. Buy the Harman Kardon Onyx Studio 9 at $186.99 if you want a boombox speaker instead.
Specifications Side By Side
| Harman Kardon Onyx Studio 4 | Harman Kardon Onyx Studio 9 | |
|---|---|---|
| Price | $100 Discontinued | $186.99 |
| Ranked | #46 of 75 in Large Size Portable Bluetooth Speakers | #13 of 72 in Boombox Size Portable Bluetooth Speakers |
| App | Yes (HK Connect) | Yes (Harman Kardon One app) |
| Aux Input | Yes | - |
| Battery Life | 8 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| EQ | No | Yes (App EQ) |
| IP Rating | None | None |
| Party Mode | Yes (Connect+ up to 100 speakers) | Yes (Auracast) |
| Power Bank | No | - |
| TWS | Yes | Yes |
| Weight | 4.5 lbs / 2.06 kg | 9.3 lbs / 4.2 kg |
| Bluetooth Codecs | SBC | SBC |
| Built in Microphone | Yes | - |
| Power Input | DC Barrel Connector (19V/2.1A) | AC Power Cable (2-Prong) |
| Stereo | Yes | Yes |
| Bluetooth Version | 4.2 | 5.3 |
| Drivers | 2x 75mm woofers, 2x 20mm tweeters | 120mm woofer + 3x 20mm tweeters |
| Dimensions | 11.4" x 11.4" x 5.1" (290 x 290 x 130 mm) | 11.4" x 11.3" x 5.1" (289.2 x 287.5 x 130 mm) |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) | - |
| Output Power | 60W | 50W RMS |
| Discontinued | Yes | - |
| Digital Aux Input | No | No |
| Bass Extension (-10dB) | - | 41Hz |
| Max Volume | - | 101dB |
| USB Playback | - | No |
The Two Speakers In Full
Harman Kardon Onyx Studio 4: $100 Discontinued
Pros: Balanced sound quality with deep resonant bass and crisp treble, large dynamic range. Multi-host Bluetooth connectivity for 2 phones, daisy chaining up to 100 speakers. Elegant modern design with smooth curves and premium materials.
Cons: 8 hour battery at medium volume. Not at loud as others. Not as deep of bass as the newer Onyx. External AC power brick for charging. Discontinued.
| App | Yes (HK Connect) |
|---|---|
| Aux Input | Yes |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 4.2 |
| Built in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 11.4" x 11.4" x 5.1" (290 x 290 x 130 mm) |
| Discontinued | Yes |
| Drivers | 2x 75mm woofers, 2x 20mm tweeters |
| EQ | No |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) |
| IP Rating | None |
| Output Power | 60W |
| Party Mode | Yes (Connect+ up to 100 speakers) |
| Power Bank | No |
| Power Input | DC Barrel Connector (19V/2.1A) |
| Stereo | Yes |
| TWS | Yes |
| Weight | 4.5 lbs / 2.06 kg |
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- Links
- Reviews, Comparisons and Sound Samples
Harman Kardon Onyx Studio 9: $186.99 Amazon
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.
| 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 |
| 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 |
- Buy Used
As an eBay Partner, I may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Harman Kardon Onyx Studio 9 vs Zealot ZE41
- Harman Kardon Onyx Studio 9 vs Harman Kardon Onyx Studio 7
- Harman Kardon Onyx Studio 9 vs Zealot ZE21
- Harman Kardon Onyx Studio 9 vs Harman Kardon Onyx Studio 6
- Harman Kardon Onyx Studio 9 vs Zealot S89
- Harman Kardon Onyx Studio 9 vs Harman Kardon Onyx Studio 8
- Harman Kardon Onyx Studio 9 vs JBL Boombox 4
- Harman Kardon Onyx Studio 9 vs Vifa Copenhagen 2.0
- See all 29 comparisons
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Product prices and availability were last checked August 11, 2026 at 1:09 PM UTC 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.