Short answer: the Harman Kardon Onyx Studio 9, if you are buying new. The Harman Kardon Onyx Studio 6 ranks higher than the Zealot S78 (#13 vs #97 of 98 boombox speakers) but is discontinued; its replacement, the Harman Kardon Onyx Studio 9, is rated 4.1/5 at $189.99 and is still sold new.
The Harman Kardon Onyx Studio 6 is the better-sounding, lighter pick. Harman Kardon Onyx Studio 6 uses a 120mm woofer, 25mm tweeter and passive radiator. At 6.5 lbs (2.94 kg) it weighs noticeably less than the Zealot S78 at 9.7 lbs (4.4 kg). It links with other speakers (Wireless Dual Sound), which the Zealot S78 cannot. Watch for: Warm tuning with boosted bass, and not as loud as others.
The Zealot S78 is the longer-running option. A robust 9.7 lbs (4.4 kg) party speaker with claimed 120W RMS output, IP67 protection, USB-C charging, a power-bank function, aux, USB and microSD playback, TWS pairing and multiple EQ modes. It is rated for 40 hours of battery against 8 for the Harman Kardon Onyx Studio 6. It has an adjustable EQ, which the Harman Kardon Onyx Studio 6 lacks. It plays in stereo from a single unit, unlike the Harman Kardon Onyx Studio 6. Watch for: At high volume, reviews report distortion and fluctuating level, so its headline power is more useful below its maximum setting.
Buy the Harman Kardon Onyx Studio 9, the replacement for the discontinued Harman Kardon Onyx Studio 6; it is rated higher for sound quality than the Zealot S78.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Harman Kardon Onyx Studio 6 | Zealot S78 | |
|---|---|---|
| Price | $130 Discontinued | $159.68 |
| Ranked | #13 of 98 in Boombox Size Portable Bluetooth Speakers | #97 of 98 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | Yes |
| Bass Extension (-10dB) | 37Hz | - |
| Battery Life | 8 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| Built-in Microphone | Yes | No |
| IP Rating | IPX7 | IP67 |
| Bluetooth Latency | 180ms | - |
| Maximum SPL | 96dB (measured by Alan Ross Reviews) | - |
| Party Mode | Yes (Wireless Dual Sound) | No |
| 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) | 9.7 lbs (4.4 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| App | No | No |
| EQ | No | Yes (multiple modes) |
| Power Bank | No | Yes (USB-A) |
| USB Playback | No | Yes |
| Bluetooth Version | 4.2 | 5.3 |
| Amplifier Power | 50W RMS | 120W RMS / 150W peak |
| Dimensions | 5” x 11.5” x 11.2” (128 x 291 x 284 mm) | 16.1” x 6.6” x 7.3” (410 x 167 x 185 mm) |
| Drivers | 1x 120mm (4.7”) woofer + 1x 25mm (1”) tweeter + 1x passive radiator | 2x ~120mm (4.72”) woofers + 2x ~42mm tweeters + 2x passive radiators |
| Digital Aux Input | No | No |
| Strap | No | Yes (detachable shoulder strap) |
| MicroSD Playback | - | Yes |
Related Speaker Comparisons
How Harman Kardon Onyx Studio 6 compares with other leading options:
- 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 On-The-Go 2 Plus vs Harman Kardon Onyx Studio 6
- JBL Partybox Encore Essential 2 vs Harman Kardon Onyx Studio 6
Prices on this page were last checked October 12, 2026 at 4:13 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 $130 eBay
Newer model: the Harman Kardon Onyx Studio 9, ranked lower, rated 4.1/5, released Dec 2024.
Older models: the Harman Kardon Onyx Studio 5 (ranked lower, rated 3.9/5) and the Harman Kardon Onyx Studio 4 (rated 3.3/5). See every Harman Kardon Onyx Studio generation.
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 →
| Released | Sep 2019 (7 years ago) |
|---|---|
| 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 →
- Alan Ross Reviews: https://www.youtube.com/watch?v=K5ImoaGw3t0
- 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!
- That Speaker Guy: Harman Kardon Onyx Studio 6 vs Devialet Mania
- Ezekielo: Citation 200 vs Onyx Studio 6 vs Bose Portable Speaker Sound Comparison
- 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 64 comparisons
Zealot S78: $159.68 Amazon $159.68 AliExpress $91.38 eBay
Pros: A robust 4.4kg party speaker with claimed 120W RMS output, IP67 protection, USB-C charging, a power-bank function, aux, USB and microSD playback, TWS pairing and multiple EQ modes. Reviews find it very loud with useful bass and long claimed battery life, making it a credible choice for outdoor gatherings.
Cons: At high volume, reviews report distortion and fluctuating level, so its headline power is more useful below its maximum setting. It has no app-based EQ, and the bass and midrange refinement do not match better-established boombox speakers; assess its sound in person if tonal accuracy matters.
Full Zealot S78 review and specifications →
| Released | May 2023 (3 years ago) |
|---|---|
| Amplifier Power | 120W RMS / 150W peak |
| App | No |
| Aux Input | Yes |
| Battery Life | 40 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 16.1” x 6.6” x 7.3” (410 x 167 x 185 mm) |
| Drivers | 2x ~120mm (4.72”) woofers + 2x ~42mm tweeters + 2x passive radiators |
| EQ | Yes (multiple modes) |
| IP Rating | IP67 |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | Yes (USB-A) |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | Yes (detachable shoulder strap) |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 9.7 lbs (4.4 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Jay’s Straight Up Reviews & More: DBSOARS F29 Max vs Zealot S78 🛜 (5B) Budget Bluetooth Boombox Basement Battle 🔊 Bass Modes Enabled More from JaysStraightUpReviews →
- Jay’s Straight Up Reviews & More: W-King X20 vs Zealot S78 Bluetooth Boombox Battle Outdoor Tailgater Special 🚗 Let the Whoopin’ Begin
- Head-to-Head Comparisons