Harman Kardon Go + Play 3 vs Zealot ZE21

Last updated: August 28, 2026

Short answer: the Harman Kardon Go + Play 3 on measured sound quality, the Zealot ZE21 on price. The Harman Kardon Go + Play 3 ranks #3 of 73 boombox speakers at $385. The Zealot ZE21 ranks #15 at $247.41, $137.59 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 ZE21 offers: Great value for the bass performance, play time and max volume in the boombox class, though the Zealot ZE41 now beats it out. Watch for: A little rolled off up top and not that balanced through the rest of the range. Clarity isn’t as good as better speakers. Bass EQ is bloated and muddy sounding

Buy the Harman Kardon Go + Play 3 if sound quality matters more than the price. Buy the Zealot ZE21 if the price matters more than sound quality.

Battery life favors the Zealot ZE21: rated for 40 hours against 8 hours for the Harman Kardon Go + Play 3.

If water resistance matters to you, the Zealot ZE21 at IPX6 (powerful water jets) holds up far better than the Harman Kardon Go + Play 3 at no water resistance.

Buy the Harman Kardon Go + Play 3 at Amazon ($385) →Buy the Zealot ZE21 at Amazon ($247.41) →

Harman Kardon Go + Play 3 vs Zealot ZE21

Specifications Side By Side

Harman Kardon Go + Play 3 Zealot ZE21
Price$385$247.41
Ranked#3 of 73 in Boombox Size Portable Bluetooth Speakers#15 of 73 in Boombox Size Portable Bluetooth Speakers
AppYes (Harman Kardon One app)No
Aux Latency112ms-
Bass Extension (-10dB)35Hz36Hz
Battery Life8 hours (Manufacturer specified)40 hours (Manufacturer specified)
Built in MicrophoneYesNo
EQYes (App EQ)Yes (multiple modes)
IP RatingNoneIPX6
Bluetooth Latency120ms-
Max Volume103dB116dB
Power InputAC Power brickUSB-C
StereoYesYes
OmnidirectionalNoNo
TWSYesYes
Weight10.4 lbs / 4.7 kg20.4 lbs / 9.27 kg
Bluetooth CodecsSBC, AACSBC
Power BankYesYes (USB-A + USB-C)
Party ModeNoYes (PartyAdd up to 100 speakers)
USB PlaybackNoYes
Bluetooth Version5.2-
Output Power160W RMS250W
Dimensions17.3" x 9.4" x 7.6" (439 x 240 x 192 mm)16.7" x 10.3" x 14.3" (424 x 262 x 363 mm)
Aux InputYesYes
Drivers1x 130mm (5") subwoofer + 2x 70mm midrange drivers + 2x 20mm tweeters130W subwoofer + 2x 50mm woofers + passive radiators
Digital Aux InputNoNo
MicroSD Playback-Yes
Buy the Harman Kardon Go + Play 3 at Amazon ($385) →Buy the Zealot ZE21 at Amazon ($247.41) →

Other pairings from the same speaker class worth checking:

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

Harman Kardon Go + Play 3 ranking card

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 →

AppYes (Harman Kardon One app)
Aux InputYes
Aux Latency112ms
Bass Extension (-10dB)35Hz
Battery Life8 hours (Manufacturer specified)
Bluetooth CodecsSBC, AAC
Bluetooth Latency120ms
Bluetooth Version5.2
Built in MicrophoneYes
Digital Aux InputNo
Dimensions17.3" x 9.4" x 7.6" (439 x 240 x 192 mm)
Drivers1x 130mm (5") subwoofer + 2x 70mm midrange drivers + 2x 20mm tweeters
EQYes (App EQ)
IP RatingNone
Max Volume103dB
OmnidirectionalNo
Output Power160W RMS
Party ModeNo
Power BankYes
Power InputAC Power brick
StereoYes
TWSYes
USB PlaybackNo
Weight10.4 lbs / 4.7 kg
Check current price at Amazon ($385) →Search eBay for Harman Kardon Go + Play 3 →

Zealot ZE21: $247.41 Amazon Aliexpress eBay

Zealot ZE21 ranking card

Pros: Great value for the bass performance, play time and max volume in the boombox class, though the Zealot ZE41 now beats it out.

Cons: A little rolled off up top and not that balanced through the rest of the range. Clarity isn’t as good as better speakers. Bass EQ is bloated and muddy sounding

Full Zealot ZE21 review and specifications →

AppNo
Aux InputYes
Bass Extension (-10dB)36Hz
Battery Life40 hours (Manufacturer specified)
Bluetooth CodecsSBC
Built in MicrophoneNo
Digital Aux InputNo
Dimensions16.7" x 10.3" x 14.3" (424 x 262 x 363 mm)
Drivers130W subwoofer + 2x 50mm woofers + passive radiators
EQYes (multiple modes)
IP RatingIPX6
Max Volume116dB
MicroSD PlaybackYes
OmnidirectionalNo
Output Power250W
Party ModeYes (PartyAdd up to 100 speakers)
Power BankYes (USB-A + USB-C)
Power InputUSB-C
StereoYes
TWSYes
USB PlaybackYes
Weight20.4 lbs / 9.27 kg
Check current price at Amazon ($247.41) →Check current price at Aliexpress ($187.15) →Search eBay for Zealot ZE21 →