Short answer: the Zealot S89 for value, the Onyx Studio 8 for a lighter, warmer sound. The S89 is a great value for bass performance, play time and max volume in the boombox class, though it is on the heavy side. The Onyx Studio 8 has warm sound with boosted bass but is not as loud as others.
Buy the Zealot S89 new; the Harman Kardon Onyx Studio 8 is no longer sold new, so it only makes sense as a used find.
If water resistance matters to you, the Zealot S89 at IPX6 (powerful water jets) holds up far better than the Harman Kardon Onyx Studio 8 at no water resistance.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Specifications Side By Side
| Harman Kardon Onyx Studio 8 | Zealot S89 | |
|---|---|---|
| Price | $199.00 Discontinued | $259.99 |
| Ranked | #12 of 90 in Boombox Size Portable Bluetooth Speakers | #19 of 90 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | Yes |
| Aux Latency | 42ms | - |
| Bass Extension (-10dB) | 35Hz | 36Hz |
| Battery Life | 8 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| Built-in Microphone | Yes | No |
| IP Rating | None | IPX6 |
| Bluetooth Latency | 175ms | - |
| Maximum SPL | 96dB (measured by Alan Ross Reviews) | - |
| Power Input | DC Barrel Connector (19V/2.1A) | USB-C |
| Stereo | Partially (1 woofer) | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 7.3 lbs (3.3 kg) | 16.1 lbs (7.3 kg) |
| App | Yes (Harman Kardon One app) | No |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| Power Bank | No | Yes (USB-A + USB-C) |
| EQ | Yes (App EQ) | Yes (multiple modes) |
| Party Mode | No | Yes (PartyAdd up to 100 speakers) |
| USB Playback | No | Yes |
| Bluetooth Version | 5.2 | 5.3 |
| Amplifier Power | 50W RMS | 250W |
| Dimensions | 10.6” x 11.9” x 6.3” (268 x 302.5 x 159.5 mm) | 21.2” x 10.4” x 9.4” (538 x 265 x 240 mm) |
| Drivers | 120mm woofer + 2x 20mm tweeters | 130W subwoofer + 2x 40mm drivers + 2x tweeters |
| Digital Aux Input | No | No |
| Strap | No | No |
| MicroSD Playback | - | Yes |
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- 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 October 2, 2026 at 10:18 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: $199.00 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!
- Head-to-Head Comparisons
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- Harman Kardon Onyx Studio 8 vs Harman Kardon Onyx Studio 9
- Harman Kardon Onyx Studio 8 vs Aiwa Exos-9
- Harman Kardon Onyx Studio 8 vs JBL Partybox Encore Essential
- Harman Kardon Onyx Studio 8 vs Zealot ZE51
- See all 74 comparisons
Zealot S89: $259.99 Amazon AliExpress eBay
Pros: A 7.3kg boombox with a claimed 36Hz bass extension, 40-hour battery life, IPX6 protection, USB-C charging, aux, USB and microSD playback, TWS and multi-speaker PartyAdd. Listener comparisons find it capable of very high output and substantial bass for outdoor use. A great value for its bass, battery life and maximum volume. Measured bass extension of 36Hz (-10dB).
Cons: At high volume, listener reports describe the bass as loose or muddy and the overall balance as less clear than better boombox speakers. The heavy cabinet and basic finish also make it less polished for daily portability, while its multiple EQ modes cannot substitute for a genuinely neutral tuning.
Full Zealot S89 review and specifications →
| Amplifier Power | 250W |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | 36Hz |
| Battery Life | 40 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 21.2” x 10.4” x 9.4” (538 x 265 x 240 mm) |
| Drivers | 130W subwoofer + 2x 40mm drivers + 2x tweeters |
| EQ | Yes (multiple modes) |
| IP Rating | IPX6 |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Party Mode | Yes (PartyAdd up to 100 speakers) |
| Power Bank | Yes (USB-A + USB-C) |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | No |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 16.1 lbs (7.3 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Oluv Patreon: Zealot S89 vs Yeahbox Boom Max3 - indoor listening test More from Oluv’Sone →
- Oluv Patreon: Zealot S89 vs Yeahbox Sonic Boom Max3 - outdoor test
- Dominik Reviews: Zealot S89 vs JBL Boombox 4 - JBL Alternative? Sound Test More from Dominik Reviews →
- Jagist reviews: Jbl Boombox 4 Vs Zealot S89!!! More from Jagistreviews →
- Techder Audios: ZEALOT S89 VS ZEALOT ZE01 EXTREME POWERFULL VS COMPACTER BASS PERFORMANCE! More from techderaudios →
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