Short answer: the Onyx Studio 6, and skip the newer model. It ranks #12 of 75 boombox speakers at $130, while the Onyx Studio 9 ranks #14 and costs $189.99. Being newer did not make the 9 the better buy.
Warm, boosted bass is the Onyx Studio 6’s calling card. Reviewer Oluv rated it slightly ahead of the newer Onyx Studio 7 for sound, and its dual 75mm woofers pair with a -10dB bass extension of 37Hz against the 9’s single 120mm woofer at 41Hz. The 9’s tuning trades some of that low end for a brighter signature: notes on it call out recessed mids, a boost in the upper mids, and rolled off upper treble, with less deep bass than earlier Onyx Studio speakers.
The Onyx Studio 9 answers back with connectivity, not sound. It runs Bluetooth 5.3 against the 6’s 4.2, works with the Harman Kardon One app for EQ adjustment (the 6 has no app at all), and uses Auracast for multi-speaker pairing instead of the 6’s proprietary Wireless Dual Sound.
The water resistance gap is the real dealbreaker for the 9. The Onyx Studio 6 carries an IPX7 rating, meaning it can survive brief submersion, while the Onyx Studio 9 has no water resistance rating at all. For anything near a pool or the beach, that alone rules the 9 out.
Buy the Onyx Studio 6 for nearly every use case. It outranks the 9, costs less, sounds warmer by the site’s own notes, and is the only one of the two safe near water.
Buy the Onyx Studio 9 only if Auracast pairing or app based EQ control matters more to you than price, sound signature, or water resistance.
Want more options? Browse the full Portable Bluetooth rankings.
Specifications Side By Side
| Harman Kardon Onyx Studio 6 | Harman Kardon Onyx Studio 9 | |
|---|---|---|
| Price | $130 | $189.99 |
| Ranked | #12 of 75 in Boombox Size Portable Bluetooth Speakers | #14 of 75 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | No |
| Bass Extension (-10dB) | 37Hz | 41Hz |
| Battery Life | 8 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| Built-in Microphone | Yes | - |
| IP Rating | IPX7 | None |
| Bluetooth Latency | 180ms | - |
| Maximum SPL | 96dB (measured by Alan Ross Reviews) | 101dB (measured by Alan Ross Reviews) |
| Party Mode | Yes (Wireless Dual Sound) | Yes (Auracast) |
| Power Input | DC Barrel Connector (19V/2A) | AC Power Cable (2-Prong) |
| Stereo | No | Yes |
| Omnidirectional | No | No |
| TWS | Yes (see https://www.reddit.com/r/Bluetooth_Speakers/comments/w339x5/how_to_harman_kardon_onyx_studio_5_6_dual_sound/) | Yes |
| Weight | 6.5 lbs (2.94 kg) | 9.3 lbs (4.2 kg) |
| Bluetooth Codecs | SBC | SBC |
| App | No | Yes (Harman Kardon One app) |
| EQ | No | Yes (App EQ) |
| Power Bank | No | - |
| USB Playback | No | No |
| Bluetooth Version | 4.2 | 5.3 |
| Amplifier Power | 50W RMS | 50W RMS |
| Dimensions | 5" x 11.5" x 11.2" (128 x 291 x 284 mm) | 11.4" x 11.3" x 5.1" (289.2 x 287.5 x 130 mm) |
| Drivers | 1x 120mm (4.7") woofer + 1x 25mm (1") tweeter + 1x passive radiator | 120mm woofer + 3x 20mm tweeters |
| Digital Aux Input | No | No |
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More worthwhile head-to-heads for Harman Kardon Onyx Studio 6:
- Tribit Stormbox Blast vs Harman Kardon Onyx Studio 6
- Harman Kardon Go + Play 3 vs Harman Kardon Onyx Studio 6
- JBL Partybox Encore 2 vs Harman Kardon Onyx Studio 6
- JBL Partybox Encore Essential 2 vs Harman Kardon Onyx Studio 6
- JBL Partybox Encore vs Harman Kardon Onyx Studio 6
Prices on this page were last checked September 23, 2026 at 11:24 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 6: $130 Amazon eBay
Pros: Harman Kardon Onyx Studio 6 uses a 120mm woofer, 25mm tweeter and passive radiator. Its 2.94 kg, claimed 8 hours (Manufacturer specified) battery life, IPX7 protection, aux input and up to 96dB make it a practical option for its intended room or portable use. Measured bass extension of 37Hz (-10dB).
Cons: Bass is limited by its 37Hz specification. There is no companion app. No EQ adjustment.
Full Harman Kardon Onyx Studio 6 review and specifications →
| Amplifier Power | 50W RMS |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | 37Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Latency | 180ms |
| Bluetooth Version | 4.2 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 5" x 11.5" x 11.2" (128 x 291 x 284 mm) |
| Drivers | 1x 120mm (4.7") woofer + 1x 25mm (1") tweeter + 1x passive radiator |
| EQ | No |
| IP Rating | IPX7 |
| Maximum SPL | 96dB (measured by Alan Ross Reviews) |
| Omnidirectional | No |
| Party Mode | Yes (Wireless Dual Sound) |
| Power Bank | No |
| Power Input | DC Barrel Connector (19V/2A) |
| Stereo | No |
| TWS | Yes (see https://www.reddit.com/r/Bluetooth_Speakers/comments/w339x5/how_to_harman_kardon_onyx_studio_5_6_dual_sound/) |
| USB Playback | No |
| Weight | 6.5 lbs (2.94 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Alan Ross Reviews: Onyx Studio 7 vs Onyx Studio 6 - massive deep bass battle 😁 More from alanrossreviews →
- That Speaker Guy: Harman Kardon Onyx Studio 6 vs Devialet Mania
- Ezekielo: Citation 200 vs Onyx Studio 6 vs Bose Portable Speaker Sound Comparison
- Alan Ross Reviews: Harman Kardon Go+ Play 2 mini or Onyx Studio 6 - best speaker for bass?
- Alan Ross Reviews: Ultimate HK Onyx Studio speaker review and comparison! 8 speakers!
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Harman Kardon Onyx Studio 9: $189.99 Amazon eBay
Pros: An elegant 4.2kg living-room portable with a measured 41Hz -10dB bass point, 101dB maximum level, three tweeters, app EQ, stereo pairing and Auracast multi-speaker linking. Reviews praise its balanced, smooth presentation and non-fatiguing treble, making it a more music-focused choice than most party speakers. Measured bass extension of 41Hz (-10dB).
Cons: It has no water resistance, aux input or USB playback, and its eight-hour claimed battery life is short for an outdoor portable. Bass is less deep than some earlier Onyx Studio models, while the slightly recessed mids and rolled-off top end mean it is not the most open or detailed option; it still charges from an AC power cable rather than USB-C.
Full Harman Kardon Onyx Studio 9 review and specifications →
| Amplifier Power | 50W RMS |
|---|---|
| App | Yes (Harman Kardon One app) |
| Aux Input | No |
| 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 |
| Maximum SPL | 101dB (measured by Alan Ross Reviews) |
| Omnidirectional | No |
| 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
- Head-to-Head Comparisons
- Harman Kardon Onyx Studio 9 vs Harman Kardon Onyx Studio 7
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