Short answer: the Harman Kardon Onyx Studio 6. It ranks #11 of 73 boombox speakers by sound quality at $130; the Zealot S78 ranks #73 and costs $159.68, so there is not much of a tradeoff to weigh.
What the Harman Kardon Onyx Studio 6 offers: Warm sound with boosted bass. Oluv liked it slightly better than the newer Onyx 7. Watch for: 8 hour battery at medium volume. Not at loud as others.
What the Zealot S78 offers: 120W RMS output with 150W peak power, exceptional 40-hour battery life, power bank function, IP67 waterproof, EQ with multiple modes, dual woofers with tweeters and passive radiators, MicroSD and USB playback, AUX input, TWS stereo pairing, USB-C charging Watch for: Gets distorted above 50%. Not much bass. Volume level fluctuates at high volume.
Buy the Harman Kardon Onyx Studio 6. It ranks higher for sound quality than the Zealot S78 and costs less, so there is no real case for the other one.
If sound quality matters at all to you, skip the Zealot S78. It ranks near the bottom of the 73 boombox speakers, so look higher up the list instead.
If battery life is a priority, the Zealot S78 is rated for 40 hours versus 8 hours for the Harman Kardon Onyx Studio 6.
Specifications Side By Side
| Harman Kardon Onyx Studio 6 | Zealot S78 | |
|---|---|---|
| Price | $130 | $159.68 |
| Ranked | #11 of 73 in Boombox Size Portable Bluetooth Speakers | #73 of 73 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 | - |
| Max Volume | 96dB | - |
| Party Mode | Yes (Wireless Dual Sound) | No |
| Power Input | DC Barrel Connector (19V/2A) | USB-C |
| Stereo | Yes | 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 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 | - |
| Output 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 | 2x 75mm woofers + 2x 20mm tweeters | 2x ~120mm (4.72") woofers + 2x ~42mm tweeters + 2x passive radiators |
| Digital Aux Input | No | No |
| MicroSD Playback | - | Yes |
Related Speaker Comparisons
A few more comparisons worth a look in the same class:
- Harman Kardon Onyx Studio 8 vs Soundcore Motion Boom+
- Harman Kardon Onyx Studio 8 vs W-King X10-1
- Harman Kardon Onyx Studio 8 vs W-King T11
- Harman Kardon Onyx Studio 6 vs Zealot S95
- Harman Kardon Onyx Studio 6 vs Harman Kardon Onyx Studio 8
Prices on this page were last checked August 27, 2026 at 10:09 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: Warm sound with boosted bass. Oluv liked it slightly better than the newer Onyx 7.
Cons: 8 hour battery at medium volume. Not at loud as others.
Full Harman Kardon Onyx Studio 6 review and specifications →
| 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 | 2x 75mm woofers + 2x 20mm tweeters |
| EQ | No |
| IP Rating | IPX7 |
| Max Volume | 96dB |
| Omnidirectional | No |
| Output Power | 50W RMS |
| Party Mode | Yes (Wireless Dual Sound) |
| Power Bank | No |
| Power Input | DC Barrel Connector (19V/2A) |
| Stereo | Yes |
| 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!
- Reddit Search for Harman Kardon Onyx Studio 6 Review
- 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 Vifa Copenhagen 2.0
- Harman Kardon Onyx Studio 6 vs Zealot ZE41
- Harman Kardon Onyx Studio 6 vs JBL Partybox Encore Essential
- Harman Kardon Onyx Studio 6 vs Zealot ZE21
- Harman Kardon Onyx Studio 6 vs JBL Partybox Encore
- See all 45 comparisons
Zealot S78: $159.68 Amazon Aliexpress eBay
Pros: 120W RMS output with 150W peak power, exceptional 40-hour battery life, power bank function, IP67 waterproof, EQ with multiple modes, dual woofers with tweeters and passive radiators, MicroSD and USB playback, AUX input, TWS stereo pairing, USB-C charging
Cons: Gets distorted above 50%. Not much bass. Volume level fluctuates at high volume.
Full Zealot S78 review and specifications →
| App | No |
|---|---|
| Aux Input | Yes |
| Battery Life | 40 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| 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 |
| Output Power | 120W RMS / 150W peak |
| Party Mode | No |
| Power Bank | Yes (USB-A) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 9.7 lbs / 4.4 kg |
- Reviews, Comparisons and Sound Samples
- Jay’s Straight Up Reviews & More: W-King X20 vs Zealot S78 Bluetooth Boombox Battle Outdoor Tailgater Special 🚗 Let the Whoopin’ Begin More from JaysStraightUpReviews →
- Jay’s Straight Up Reviews & More: DBSOARS F29 Max vs Zealot S78 🛜 (5B) Budget Bluetooth Boombox Basement Battle 🔊 Bass Modes Enabled
- Reddit Search for Zealot S78 Review
- Head-to-Head Comparisons