Short answer: the Gemini GRV-650L, if you are buying new. The Harman Kardon Onyx Studio 8 ranks higher than it (#12 vs #50 of 89 boombox speakers, 4.1/5 vs 3.3/5) but is discontinued, so only consider it used; the Gemini GRV-650L is still sold new at $149.95.
Why pick the Harman Kardon Onyx Studio 8: At 3.3 kg, Harman Kardon Onyx Studio 8 combines a 120mm woofer and 2x 20mm tweeters with Bluetooth and aux. The tradeoff: Bass is limited by its 35Hz specification.
What the Gemini GRV-650L does well: Pretty amazing value for the money. The tradeoff: Not quite as deep bass as the top ranked speakers.
Buy the Gemini GRV-650L new; the Harman Kardon Onyx Studio 8 is no longer sold new, so it only makes sense as a used find.
There is a real gap in water resistance: the Gemini GRV-650L at IPX5 (water jets) against the Harman Kardon Onyx Studio 8, which has no water resistance.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Harman Kardon Onyx Studio 8 | Gemini GRV-650L | |
|---|---|---|
| Price | $197.90 Discontinued | $149.95 |
| Ranked | #12 of 89 in Boombox Size Portable Bluetooth Speakers | #50 of 89 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | Yes |
| Aux Latency | 42ms | - |
| Bass Extension (-10dB) | 35Hz | ~47Hz |
| Battery Life | 8 hours (Manufacturer specified) | 9 hours (Manufacturer specified) |
| Built-in Microphone | Yes | No |
| IP Rating | None | IPX5 |
| Bluetooth Latency | 175ms | - |
| Maximum SPL | 96dB (measured by Alan Ross Reviews) | 104dB (Manufacturer specified) |
| Power Input | DC Barrel Connector (19V/2.1A) | USB-C |
| Stereo | Partially (1 woofer) | Partially (1 woofer) |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 7.3 lbs (3.3 kg) | 15.7 lbs (7.1 kg) |
| App | Yes (Harman Kardon One app) | No |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| Power Bank | No | Yes |
| EQ | Yes (App EQ) | No |
| Party Mode | No | No |
| USB Playback | No | Yes |
| Bluetooth Version | 5.2 | 5.3 |
| Amplifier Power | 50W RMS | 320W |
| Dimensions | 10.6” x 11.9” x 6.3” (268 x 302.5 x 159.5 mm) | 10.9” x 10.2” x 14.4” (277 x 260 x 366 mm) |
| Drivers | 120mm woofer + 2x 20mm tweeters | 6.5” woofer + tweeter |
| Digital Aux Input | No | No |
| Strap | No | No |
| MicroSD Playback | - | Yes |
| FM Tuner | - | Yes |
Related Speaker Comparisons
How Harman Kardon Onyx Studio 8 compares with other leading options:
- Tribit Stormbox Blast vs Harman Kardon Onyx Studio 8
- Harman Kardon Go + Play 3 vs Harman Kardon Onyx Studio 8
- JBL Partybox Encore 2 vs Harman Kardon Onyx Studio 8
- JBL PartyBox On-The-Go 2 Plus vs Harman Kardon Onyx Studio 8
- JBL Partybox Encore Essential 2 vs Harman Kardon Onyx Studio 8
Prices on this page were last checked September 30, 2026 at 2:57 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 8: $197.90 Discontinued Amazon eBay
Newer model: the Harman Kardon Onyx Studio 9, ranked lower, rated 4.1/5.
Pros: At 3.3 kg, Harman Kardon Onyx Studio 8 combines a 120mm woofer and 2x 20mm tweeters with Bluetooth and aux. Claimed 8 hours (manufacturer specified) battery life and up to 96db make its feature set practical for its intended room or portable use. A built-in microphone and the Harman Kardon One app with EQ. Measured bass extension of 35Hz (-10dB).
Cons: Bass is limited by its 35Hz specification. Warm tuning with boosted bass, not as loud as others, and no water resistance rating. Discontinued.
Full Harman Kardon Onyx Studio 8 review and specifications →
| Amplifier Power | 50W RMS |
|---|---|
| App | Yes (Harman Kardon One app) |
| Aux Input | Yes |
| Aux Latency | 42ms |
| Bass Extension (-10dB) | 35Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Latency | 175ms |
| Bluetooth Version | 5.2 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 10.6” x 11.9” x 6.3” (268 x 302.5 x 159.5 mm) |
| Drivers | 120mm woofer + 2x 20mm tweeters |
| EQ | Yes (App EQ) |
| IP Rating | None |
| Maximum SPL | 96dB (measured by Alan Ross Reviews) |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | No |
| Power Input | DC Barrel Connector (19V/2.1A) |
| Stereo | Partially (1 woofer) |
| Strap | No |
| TWS | Yes |
| USB Playback | No |
| Weight | 7.3 lbs (3.3 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Alan Ross Reviews: Harman Kardon Onyx Studio 8 review - part 2 of 3 More from alanrossreviews →
- Alan Ross Reviews: Onyx Studio 8 vs HK Onyx 6, Xtreme 3, PartyBox Encore, Go+ Play, Bag of Riddim! part 3 of 3
- Alan Ross Reviews: Dead room vs Live room - Onyx studio 8 self tuning test! part 1 of 3
- Alan Ross Reviews: Ultimate HK Onyx Studio speaker review and comparison! 8 speakers!
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Gemini GRV-650L: $149.95 Amazon eBay
Pros: Pretty amazing value for the money. Decently deep bass, not quite as good as top ranked speakers. Included wireless microphone and remote control. Measured bass extension of ~47Hz (-10dB).
Cons: Not quite as deep bass as the top ranked speakers.
Full Gemini GRV-650L review and specifications →
| Amplifier Power | 320W |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | ~47Hz |
| Battery Life | 9 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 10.9” x 10.2” x 14.4” (277 x 260 x 366 mm) |
| Drivers | 6.5” woofer + tweeter |
| EQ | No |
| FM Tuner | Yes |
| IP Rating | IPX5 |
| Maximum SPL | 104dB (Manufacturer specified) |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | Yes |
| Power Input | USB-C |
| Stereo | Partially (1 woofer) |
| Strap | No |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 15.7 lbs (7.1 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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