Short answer: the Zealot S89, if you are buying new. The Harman Kardon Onyx Studio 6 ranks higher than it (#13 vs #19 of 90 boombox speakers, 4.1/5 vs 4.0/5) but is discontinued, so only consider it used; the Zealot S89 is still sold new at $259.99.
What the Harman Kardon Onyx Studio 6 gets right: Warm sound with boosted bass. The catch: 8 hour battery at medium volume.
On the Zealot S89 side: A great value for the bass performance, play time and max volume in the boombox class. Set against that: On the heavy side.
Buy the Zealot S89, since the Harman Kardon Onyx Studio 6 is discontinued and only worth hunting down used.
Want more options? Browse the full Portable Bluetooth rankings.
Specifications Side By Side
| Harman Kardon Onyx Studio 6 | Zealot S89 | |
|---|---|---|
| Price | $130 Discontinued | $259.99 |
| Ranked | #13 of 90 in Boombox Size Portable Bluetooth Speakers | #19 of 90 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | Yes |
| Bass Extension (-10dB) | 37Hz | 36Hz |
| Battery Life | 8 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| Built-in Microphone | Yes | No |
| IP Rating | IPX7 | IPX6 |
| Bluetooth Latency | 180ms | - |
| Maximum SPL | 96dB (measured by Alan Ross Reviews) | - |
| Party Mode | Yes (Wireless Dual Sound) | Yes (PartyAdd up to 100 speakers) |
| Power Input | DC Barrel Connector (19V/2A) | USB-C |
| 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) | 16.1 lbs (7.3 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| App | No | No |
| EQ | No | Yes (multiple modes) |
| Power Bank | No | Yes (USB-A + USB-C) |
| USB Playback | No | Yes |
| Bluetooth Version | 4.2 | 5.3 |
| Amplifier Power | 50W RMS | 250W |
| Dimensions | 5” x 11.5” x 11.2” (128 x 291 x 284 mm) | 21.2” x 10.4” x 9.4” (538 x 265 x 240 mm) |
| Drivers | 1x 120mm (4.7”) woofer + 1x 25mm (1”) tweeter + 1x passive radiator | 130W subwoofer + 2x 40mm drivers + 2x tweeters |
| Digital Aux Input | No | No |
| Strap | No | No |
| MicroSD Playback | - | Yes |
Related Speaker Comparisons
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 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 6: $130 Discontinued Amazon eBay
Newer model: the Harman Kardon Onyx Studio 9, ranked lower, rated 4.1/5.
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. Warm tuning with boosted bass, and not as loud as others. Discontinued.
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 | Yes |
| 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 |
| Strap | 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!
- Head-to-Head Comparisons
- Harman Kardon Onyx Studio 6 vs Harman Kardon Onyx Studio 8
- Harman Kardon Onyx Studio 6 vs Harman Kardon Onyx Studio 7
- Harman Kardon Onyx Studio 6 vs Harman Kardon Onyx Studio 9
- Harman Kardon Onyx Studio 6 vs Yeahbox Sonic Boom Ultra
- Harman Kardon Onyx Studio 6 vs Vifa Copenhagen 2.0
- Harman Kardon Onyx Studio 6 vs Zealot ZE51
- Harman Kardon Onyx Studio 6 vs Zealot ZE41
- Harman Kardon Onyx Studio 6 vs JBL Partybox Encore Essential
- See all 57 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 →
- Head-to-Head Comparisons