Short answer: the Harman Kardon Onyx Studio 5 on measured sound quality, the Zealot S78 on price. The Harman Kardon Onyx Studio 5 ranks #19 of 73 boombox speakers at $499.99. The Zealot S78 ranks #73 at $159.68, $340.31 cheaper.
What the Harman Kardon Onyx Studio 5 offers: Elegant circular design with carrying handle. Bass-heavy with balanced mids and highs. Rechargeable Li-ion battery rated 7-8 hours at 40-50% volume. Watch for: Warm sound with boosted bass. 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 5 if sound quality is the priority over the price, or the Zealot S78 if the price is the priority over sound quality.
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 5.
Specifications Side By Side
| Harman Kardon Onyx Studio 5 | Zealot S78 | |
|---|---|---|
| Price | $499.99 | $159.68 |
| Ranked | #19 of 73 in Boombox Size Portable Bluetooth Speakers | #73 of 73 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | Yes |
| Battery Life | 8 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| IP Rating | IPX7 | IP67 |
| Party Mode | Yes (Wireless Dual Sound) | No |
| Power Input | DC Barrel Connector (19V/2.1A) | USB-C |
| Stereo | Partially (1 woofer) | 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 | 6.6 lbs / 3 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 |
| Built in Microphone | Yes | No |
| Output Power | 50W | 120W RMS / 150W peak |
| Dimensions | 11.3" x 11.3" (285.8 x 285.8 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 Go + Play 2 vs Tribit Stormbox Blast 2
- Harman Kardon Go + Play 2 vs JBL Partybox On the Go
- Harman Kardon Go + Play 2 vs Bumpboxx Flare 6
- JBL Boombox 2 vs Zealot S78
- Harman Kardon Onyx Studio 5 vs Zealot S95
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.
As an eBay Partner, we may be compensated if you make a purchase.
The Two Speakers In Full
Harman Kardon Onyx Studio 5: $499.99 Amazon eBay
Pros: Elegant circular design with carrying handle. Bass-heavy with balanced mids and highs. Rechargeable Li-ion battery rated 7-8 hours at 40-50% volume.
Cons: Warm sound with boosted bass. 8 hour battery at medium volume. Not at loud as others.
Full Harman Kardon Onyx Studio 5 review and specifications →
| App | No |
|---|---|
| Aux Input | Yes |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Built in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 11.3" x 11.3" (285.8 x 285.8 mm) |
| Drivers | 2x 75mm woofers + 2x 20mm tweeters |
| EQ | No |
| IP Rating | IPX7 |
| Omnidirectional | No |
| Output Power | 50W |
| Party Mode | Yes (Wireless Dual Sound) |
| Power Bank | No |
| Power Input | DC Barrel Connector (19V/2.1A) |
| Stereo | Partially (1 woofer) |
| 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 | 6.6 lbs / 3 kg |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Harman Kardon Onyx Studio 5 vs JBL Boombox 3 Wifi
- Harman Kardon Onyx Studio 5 vs Harman Kardon Go + Play 2
- Harman Kardon Onyx Studio 5 vs JBL Boombox 4
- Harman Kardon Onyx Studio 5 vs JBL Boombox 3
- Harman Kardon Onyx Studio 5 vs Tribit Stormbox Blast 2
- Harman Kardon Onyx Studio 5 vs Zealot S89
- Harman Kardon Onyx Studio 5 vs LG Xboom Stage 301
- Harman Kardon Onyx Studio 5 vs Zealot ZE21
- See all 47 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