Short answer: the Harman Kardon Go + Play 3 if sound quality matters most, the Zealot S78 if price matters most. The Harman Kardon Go + Play 3 ranks #3 of 73 boombox speakers at $385. The Zealot S78 ranks #73 at $159.68, $225.32 cheaper.
What the Harman Kardon Go + Play 3 offers: Warm sound with boosted bass. Deepest bass out of any speaker in this size. Sound is more natural than the Go + Play2. Watch for: Just a little over half as loud as the higher rated boomboxes. Only 8 hours of battery at medium volume. 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 Go + Play 3 when sound quality outweighs the price for you, and the Zealot S78 when the price outweighs sound quality instead.
The Zealot S78 is not a sound-quality pick. It sits near the bottom of the 73 boombox speakers; there are better options higher up.
Battery life favors the Zealot S78: rated for 40 hours against 8 hours for the Harman Kardon Go + Play 3.
If water resistance matters to you, the Zealot S78 at IP67 (brief submersion) holds up far better than the Harman Kardon Go + Play 3 at no water resistance.
Specifications Side By Side
| Harman Kardon Go + Play 3 | Zealot S78 | |
|---|---|---|
| Price | $385 | $159.68 |
| Ranked | #3 of 73 in Boombox Size Portable Bluetooth Speakers | #73 of 73 in Boombox Size Portable Bluetooth Speakers |
| App | Yes (Harman Kardon One app) | No |
| Aux Latency | 112ms | - |
| Bass Extension (-10dB) | 35Hz | - |
| Battery Life | 8 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| Built in Microphone | Yes | No |
| EQ | Yes (App EQ) | Yes (multiple modes) |
| IP Rating | None | IP67 |
| Bluetooth Latency | 120ms | - |
| Max Volume | 103dB | - |
| Power Input | AC Power brick | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 10.4 lbs / 4.7 kg | 9.7 lbs / 4.4 kg |
| Bluetooth Codecs | SBC, AAC | SBC |
| Power Bank | Yes | Yes (USB-A) |
| Party Mode | No | No |
| USB Playback | No | Yes |
| Bluetooth Version | 5.2 | - |
| Output Power | 160W RMS | 120W RMS / 150W peak |
| Dimensions | 17.3" x 9.4" x 7.6" (439 x 240 x 192 mm) | 16.1" x 6.6" x 7.3" (410 x 167 x 185 mm) |
| Aux Input | Yes | Yes |
| Drivers | 1x 130mm (5") subwoofer + 2x 70mm midrange drivers + 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:
- JBL Partybox Encore 2 vs W-King H10
- JBL Partybox Encore 2 vs W-King X20
- JBL Partybox Encore 2 vs Soundcore Rave Party 2
- Harman Kardon Go + Play 3 vs Zealot S95
- Harman Kardon Go + Play 3 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 Go + Play 3: $385 Amazon eBay
Pros: Warm sound with boosted bass. Deepest bass out of any speaker in this size. Sound is more natural than the Go + Play2.
Cons: Just a little over half as loud as the higher rated boomboxes. Only 8 hours of battery at medium volume. No water rating.
Setup: Use the hidden EQ modes to adjust the bass up when outside and down when inside. To adjust bass, quickly press the bluetooth and volume down buttons together, the number of light flashes tell you what mode you’re in. To adjust treble, quickly press the volume up and phone buttons at the same time, the number of yellow flashes on the light tell you what mode you are in.
Full Harman Kardon Go + Play 3 review and specifications →
| App | Yes (Harman Kardon One app) |
|---|---|
| Aux Input | Yes |
| Aux Latency | 112ms |
| Bass Extension (-10dB) | 35Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, AAC |
| Bluetooth Latency | 120ms |
| Bluetooth Version | 5.2 |
| Built in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 17.3" x 9.4" x 7.6" (439 x 240 x 192 mm) |
| Drivers | 1x 130mm (5") subwoofer + 2x 70mm midrange drivers + 2x 20mm tweeters |
| EQ | Yes (App EQ) |
| IP Rating | None |
| Max Volume | 103dB |
| Omnidirectional | No |
| Output Power | 160W RMS |
| Party Mode | No |
| Power Bank | Yes |
| Power Input | AC Power brick |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | No |
| Weight | 10.4 lbs / 4.7 kg |
- Links
- Reviews, Comparisons and Sound Samples
- Alan Ross Reviews: Harman Kardon Go+ Play 3 vs Go Play 2, the holy grail has arrived? ✔ More from alanrossreviews →
- Alan Ross Reviews: Harman Kardon Go + Play 3 hidden eq modes - world has gone crazy! 🤣
- Alan Ross Reviews: Minirig 2.1 or the Brane X or the Harman Kardon Go Play 3?
- Alan Ross Reviews: JBL Distortion Fest vs my favorite speaker today! I wasn’t expecting this!
- Mateusz Cholewa: BOGASING S8 Pro Max „HiFi” 🎶🧐🆚 Harman Kardon Go Play 3 „HiFi”🔊 More from Mateusz Cholewa →
- Oluv Patreon: Harman Kardon go+play 3 - best sounding? More from Oluv’Sone →
- Oluv Patreon: Harman Kardon go+play 3 vs Tribit Stormbox Blast - outdoor soundtest
- Oluv Patreon: Harman Kardon go+play 3 vs JBL Xtreme 4 - first impressions
- Reddit Search for Harman Kardon Go + Play 3 Review
- Head-to-Head Comparisons
- Harman Kardon Go + Play 3 vs JBL Partybox Encore 2
- Harman Kardon Go + Play 3 vs Tribit Stormbox Blast
- Harman Kardon Go + Play 3 vs Earfun Uboom X
- Harman Kardon Go + Play 3 vs JBL Partybox Encore Essential 2
- Harman Kardon Go + Play 3 vs JBL Partybox Encore
- Harman Kardon Go + Play 3 vs JBL Partybox Encore Essential
- Harman Kardon Go + Play 3 vs Harman Kardon Onyx Studio 8
- Harman Kardon Go + Play 3 vs Harman Kardon Onyx Studio 6
- 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