Short answer: the Harman Kardon Onyx Studio 8 ranks #10 of 73 boombox speakers by sound quality at $159.99; the Zealot S78 ranks #73 at $159.68. With prices this close, go by the sound-quality ranking rather than the cost.
What the Harman Kardon Onyx Studio 8 offers: Warm sound with boosted bass. Watch for: Not as loud as others. No water rating.
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 8 when sound quality outweighs the price for you, and the Zealot S78 when the price outweighs sound quality instead.
Skip the Zealot S78 if sound quality matters to you. It ranks near the bottom of the 73 boombox speakers.
If battery life is a priority, the Zealot S78 is rated for 40 hours versus 8 hours for the Harman Kardon Onyx Studio 8.
Water resistance is not close: the Zealot S78 is rated at IP67 (brief submersion), well ahead of the Harman Kardon Onyx Studio 8 at no water resistance.
Specifications Side By Side
| Harman Kardon Onyx Studio 8 | Zealot S78 | |
|---|---|---|
| Price | $159.99 | $159.68 |
| Ranked | #10 of 73 in Boombox Size Portable Bluetooth Speakers | #73 of 73 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | Yes |
| Aux Latency | 42ms | - |
| Bass Extension (-10dB) | 35Hz | - |
| Battery Life | 8 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| Built in Microphone | Yes | No |
| IP Rating | None | IP67 |
| Bluetooth Latency | 175ms | - |
| Max Volume | 96dB | - |
| Power Input | DC Barrel Connector (19V/2.1A) | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 7.3 lbs / 3.3 kg | 9.7 lbs / 4.4 kg |
| App | Yes (Harman Kardon One app) | No |
| Bluetooth Codecs | SBC | SBC |
| Power Bank | No | Yes (USB-A) |
| EQ | Yes (App EQ) | Yes (multiple modes) |
| Party Mode | No | No |
| USB Playback | No | Yes |
| Bluetooth Version | 5.2 | - |
| Output Power | 50W RMS | 120W RMS / 150W peak |
| Dimensions | 10.6" x 11.9" x 6.3" (268 x 302.5 x 159.5 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
Other pairings from the same speaker class worth checking:
- Harman Kardon Onyx Studio 6 vs Harman Kardon Onyx Studio 9
- Harman Kardon Onyx Studio 6 vs W-King D20
- Harman Kardon Onyx Studio 6 vs Soundcore Rave Party 2
- Harman Kardon Onyx Studio 8 vs Zealot S95
- Zealot S95 vs Zealot S78
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 8: $159.99 Amazon eBay
Pros: Warm sound with boosted bass.
Cons: Not as loud as others. No water rating.
Full Harman Kardon Onyx Studio 8 review and specifications →
| App | Yes (Harman Kardon One app) |
|---|---|
| Aux Input | Yes |
| Aux Latency | 42ms |
| Bass Extension (-10dB) | 35Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| 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 | 2x 75mm woofers + 2x 20mm tweeters |
| EQ | Yes (App EQ) |
| IP Rating | None |
| Max Volume | 96dB |
| Omnidirectional | No |
| Output Power | 50W RMS |
| Party Mode | No |
| Power Bank | No |
| Power Input | DC Barrel Connector (19V/2.1A) |
| Stereo | Yes |
| 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!
- Reddit Search for Harman Kardon Onyx Studio 8 Review
- Head-to-Head Comparisons
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- Harman Kardon Onyx Studio 8 vs JBL Partybox Encore Essential
- Harman Kardon Onyx Studio 8 vs JBL Partybox Encore
- Harman Kardon Onyx Studio 8 vs Zealot ZE41
- See all 44 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