Short answer: the Zealot ZE21 for value, the Harman Kardon Go + Play 2 for a warmer, bass-boosted sound. The ZE21 is a great value for bass performance, play time and max volume in the boombox class, though the ZE41 now beats it and it is a little rolled off up top. The Go + Play 2 is warm with boosted bass but is not as loud as others.
Buy the Zealot ZE21. It is rated higher for sound quality; the Harman Kardon Go + Play 2 is no longer sold new.
If battery life is a priority, the Zealot ZE21 is rated for 40 hours versus 8 hours for the Harman Kardon Go + Play 2.
If water resistance matters to you, the Zealot ZE21 at IPX6 (powerful water jets) holds up far better than the Harman Kardon Go + Play 2 at no water resistance.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Zealot ZE21 | Harman Kardon Go + Play 2 | |
|---|---|---|
| Price | $247.41 | $350 Discontinued |
| Ranked | #18 of 90 in Boombox Size Portable Bluetooth Speakers | #23 of 90 in Boombox Size Portable Bluetooth Speakers |
| App | No | No |
| Aux Input | Yes | Yes |
| Bass Extension (-10dB) | 36Hz | 40Hz |
| Battery Life | 40 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| EQ | Yes (multiple modes) | No |
| IP Rating | IPX6 | None |
| MicroSD Playback | Yes | - |
| Party Mode | Yes (PartyAdd up to 100 speakers) | Yes (Wireless Dual Sound) |
| Power Input | USB-C | AC Power brick |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | No |
| Weight | 20.4 lbs (9.27 kg) | 5.3 lbs (2.4 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| Power Bank | Yes (USB-A + USB-C) | No |
| USB Playback | Yes | No |
| Built-in Microphone | No | Yes |
| Amplifier Power | 250W | 100W AC / 30W battery |
| Dimensions | 16.7” x 10.3” x 14.3” (424 x 262 x 363 mm) | 20” x 9” x 9.5” (508 x 228.6 x 241.3 mm) |
| Drivers | 130W subwoofer + 2x 50mm woofers + passive radiators | 2x 90mm (3.5”) woofers (front and rear firing) + 2x 20mm tweeters |
| Maximum SPL | 116dB (Manufacturer specified) | 99dB (measured by Alan Ross Reviews) |
| Digital Aux Input | No | No |
| Bluetooth Version | 5.3 | 4.1 |
| Aux Latency | - | 0ms |
| Bluetooth Latency | - | 33ms |
| Strap | - | No |
Related Speaker Comparisons
More worthwhile head-to-heads for Zealot ZE21:
- Tribit Stormbox Blast vs Zealot ZE21
- Harman Kardon Go + Play 3 vs Zealot ZE21
- JBL Partybox Encore 2 vs Zealot ZE21
- JBL PartyBox On-The-Go 2 Plus vs Zealot ZE21
- JBL Partybox Encore Essential 2 vs Zealot ZE21
Prices on this page were last checked October 2, 2026 at 10:18 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
Zealot ZE21: $247.41 Amazon AliExpress eBay
Pros: The ZE21’s main attraction is unusually deep bass for a battery boombox: owner testing finds real output in the 40-50Hz region and audibility down toward the low 30s. Its TWS button can form a stereo pair with another compatible Zealot, and its large, rugged chassis gives it credible party-speaker scale. Measured bass extension of 36Hz (-10dB).
Cons: That deep-bass emphasis comes with a pronounced 60-110Hz kick-bass dip and over-loud 250-600Hz lower mids, which can make rock and pop sound hollow or boxy. The supplied sound modes do not fully correct the tuning; the most positive independent report required source-side parametric EQ. Treble is also soft and clarity trails better-tuned rivals.
Full Zealot ZE21 review and specifications →
| Amplifier Power | 250W |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | 36Hz |
| Battery Life | 40 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 16.7” x 10.3” x 14.3” (424 x 262 x 363 mm) |
| Drivers | 130W subwoofer + 2x 50mm woofers + passive radiators |
| EQ | Yes (multiple modes) |
| IP Rating | IPX6 |
| Maximum SPL | 116dB (Manufacturer specified) |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Party Mode | Yes (PartyAdd up to 100 speakers) |
| Power Bank | Yes (USB-A + USB-C) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 20.4 lbs (9.27 kg) |
- Links
- Reviews, Comparisons and Sound Samples
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- Techder Audios: JBL Boombox 4 VS Zealot ZE21 BATTLE OF THE BOOMBOXES! More from techderaudios →
- Jay’s Straight Up Reviews & More: Zealot ZE21 vs JBL Boombox 3 Tailgater Special @20ft. The Budget Beast Against the OG Boombox More from JaysStraightUpReviews →
- Head-to-Head Comparisons
Harman Kardon Go + Play 2: $350 Discontinued eBay
Newer model: the Harman Kardon Go + Play 3, ranked higher, rated 4.4/5.
Pros: At 2.4 kg, Harman Kardon Go + Play 2 combines 2x 90mm (3.5”) woofers (front and rear firing) + 2x 20mm tweeters with Bluetooth. Claimed 8 hours (manufacturer specified) battery life, up to 99db and stereo playback make its feature set practical for its intended room or portable use. Measured bass extension of 40Hz (-10dB).
Cons: Bass is limited by its 40Hz specification. There is no companion app. No EQ adjustment. Not as loud as others. Discontinued.
Full Harman Kardon Go + Play 2 review and specifications →
| Amplifier Power | 100W AC / 30W battery |
|---|---|
| App | No |
| Aux Input | Yes |
| Aux Latency | 0ms |
| Bass Extension (-10dB) | 40Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Latency | 33ms |
| Bluetooth Version | 4.1 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 20” x 9” x 9.5” (508 x 228.6 x 241.3 mm) |
| Drivers | 2x 90mm (3.5”) woofers (front and rear firing) + 2x 20mm tweeters |
| EQ | No |
| IP Rating | None |
| Maximum SPL | 99dB (measured by Alan Ross Reviews) |
| Omnidirectional | No |
| Party Mode | Yes (Wireless Dual Sound) |
| Power Bank | No |
| Power Input | AC Power brick |
| Stereo | Yes |
| Strap | No |
| TWS | No |
| USB Playback | No |
| Weight | 5.3 lbs (2.4 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 →
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- Alan Ross Reviews: HK Go+ Play vs Soundcore Motion Boom - biggest bass battle ever!!!!!!!!!!!!
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