Short answer: the Earfun Uboom X. It ranks #1 of 74 boombox speakers by sound quality at $128; the Zealot ZE51 ranks #14 and costs $296.39, so there is little reason to consider the other one.
The case for the Zealot ZE51: Cleaner sound and a wider stereo soundstage than the Zealot ZE41, with less distortion at high volume for better instrumental detail and clarity. Watch for: The Zealot ZE41 still wins on raw bass depth and price. Large and heavy like the rest of the boombox class, and clarity still isn’t up to dedicated hi-fi speakers.
On the Earfun Uboom X side: Tuned by Oluv and he knocked it out of the park again. Deeper bass than the Stormbox Blast. Extremely neutral, possibly the best of any modern Bluetooth speaker slightly behind the Vifa Helsinki. The catch: The out of the box 0.33 firmware and EQ sounds horrible. Some people have mentioned sound interruption issues when using 2 in TWS, I don’t have this issue with my Pixel 7 Pro, try disabling AAC in that case
Buy the Earfun Uboom X. It ranks higher for sound quality than the Zealot ZE51 and costs less, which settles it without a real tradeoff to make.
Specifications Side By Side
| Zealot ZE51 | Earfun Uboom X | |
|---|---|---|
| Price | $296.39 after coupon | $128 Discontinued |
| Ranked | #14 of 74 in Boombox Size Portable Bluetooth Speakers | #1 of 74 in Boombox Size Portable Bluetooth Speakers |
| App | Yes | Yes (Earfun Audio app) |
| Aux Input | Yes | Yes |
| Battery Capacity | 48000mAh (12x4000mAh) | - |
| Bluetooth Version | 5.3 | 5.3 |
| Dimensions | 22.1" x 9.4" x 13" (562 x 238 x 331 mm) | 15.7" x 5.9" x 8.5" (400 x 150 x 215 mm) |
| EQ | Yes (Hi-Res, 3D Surround, Extra Bass, Vocal and other sound modes) | Yes (App EQ) |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) | - |
| IP Rating | IPX5 | IP67 |
| Microphone Input | Yes (Karaoke mode) | - |
| MicroSD Playback | Yes | - |
| Output Power | 250W | 80W |
| Power Bank | Yes (USB-A + USB-C) | Yes (USB-C) |
| Power Input | Type-C | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| USB Playback | Yes | No |
| Weight | 26 lbs / 11.81 kg | 9 lbs / 4.1 kg |
| Digital Aux Input | No | No |
| Aux Latency | - | 16ms |
| Bass Extension (-10dB) | - | ~38Hz |
| Battery Life | - | 30 hours (Manufacturer specified) |
| Bluetooth Codecs | - | AAC, SBC |
| Built in Microphone | - | Yes |
| Bluetooth Latency | - | SBC Video mode 48ms, AAC Video mode 128ms, SBC 112ms, AAC 176ms |
| Max Volume | - | 110dB |
| Party Mode | - | Yes (Party Connect mode, up to 50 speakers) |
| FM Tuner | - | No |
| Drivers | - | 2x 102mm (4") woofers + 2x 20mm tweeters |
| Discontinued | - | Yes |
Related Speaker Comparisons
A few more comparisons worth a look in the same class:
- Harman Kardon Onyx Studio 9 vs JBL Partybox Encore Essential 2
- Bugani Boost Max vs Harman Kardon Onyx Studio 9
- Harman Kardon Onyx Studio 6 vs Zealot ZE41
- Earfun Uboom X vs Zealot ZE41
- Earfun Uboom X vs Tribit Stormbox Blast 2
Prices on this page were last checked August 29, 2026 at 8:52 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 ZE51: $296.39 after coupon Amazon Aliexpress eBay
Pros: Cleaner sound and a wider stereo soundstage than the Zealot ZE41, with less distortion at high volume for better instrumental detail and clarity.
Cons: The Zealot ZE41 still wins on raw bass depth and price. Large and heavy like the rest of the boombox class, and clarity still isn’t up to dedicated hi-fi speakers.
Full Zealot ZE51 review and specifications →
| App | Yes |
|---|---|
| Aux Input | Yes |
| Battery Capacity | 48000mAh (12x4000mAh) |
| Bluetooth Version | 5.3 |
| Digital Aux Input | No |
| Dimensions | 22.1" x 9.4" x 13" (562 x 238 x 331 mm) |
| EQ | Yes (Hi-Res, 3D Surround, Extra Bass, Vocal and other sound modes) |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) |
| IP Rating | IPX5 |
| MicroSD Playback | Yes |
| Microphone Input | Yes (Karaoke mode) |
| Omnidirectional | No |
| Output Power | 250W |
| Power Bank | Yes (USB-A + USB-C) |
| Power Input | Type-C |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 26 lbs / 11.81 kg |
- Links
- Reviews, Comparisons and Sound Samples
- J_Strat Battles: ZEALOT ZE51 VS JBL BOOMBOX 4 (OLD FIRMWARE VERSION) 🧨🧨🧨
- J_Strat Battles: Zealot ZE51 VS ZE21
- J_Strat Battles: ZEALOT ZE51 VS W-KING X20 🥳🥳
- J_Strat Battles: Zealot ZE51 vs ZE21 bass boost/vocal eq battle 💪🏻😎
- J_Strat Battles: Zealot ZE51 short hz test video
- Reddit Search for Zealot ZE51 Review
- Head-to-Head Comparisons
Earfun Uboom X: $128 Discontinued Myearfun Amazon eBay
Pros: Tuned by Oluv and he knocked it out of the park again. Deeper bass than the Stormbox Blast. Extremely neutral, possibly the best of any modern Bluetooth speaker slightly behind the Vifa Helsinki. This is the only speaker that sounds correct at every single volume level due to Oluv’s individual EQ settings at each volume level. Other speakers will need a different EQ at each volume level. Amazing sounding at low levels as it boosts bass and treble at low levels to account for the equal-loudness contour. Just considering the midrange and treble, this speaker is better sounding than the Earfun Uboom L.
Cons: The out of the box 0.33 firmware and EQ sounds horrible. Some people have mentioned sound interruption issues when using 2 in TWS, I don’t have this issue with my Pixel 7 Pro, try disabling AAC in that case. Discontinued.
Setup: Please update it using the Earfun app (Android or iOS) and select an Oluv EQ. The Earfun app has sound profiles created by Oluv for Studio, Indoor, Indoor+, Outdoor, Outdoor+, BOOM xxX, and Ground 0 which are all fantastic. Oluv has a newer firmware pack that brings it up a few more notches of neutral
Full Earfun Uboom X review and specifications →
| App | Yes (Earfun Audio app) |
|---|---|
| Aux Input | Yes |
| Aux Latency | 16ms |
| Bass Extension (-10dB) | ~38Hz |
| Battery Life | 30 hours (Manufacturer specified) |
| Bluetooth Codecs | AAC, SBC |
| Bluetooth Latency | SBC Video mode 48ms, AAC Video mode 128ms, SBC 112ms, AAC 176ms |
| Bluetooth Version | 5.3 |
| Built in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 15.7" x 5.9" x 8.5" (400 x 150 x 215 mm) |
| Discontinued | Yes |
| Drivers | 2x 102mm (4") woofers + 2x 20mm tweeters |
| EQ | Yes (App EQ) |
| FM Tuner | No |
| IP Rating | IP67 |
| Max Volume | 110dB |
| Omnidirectional | No |
| Output Power | 80W |
| Party Mode | Yes (Party Connect mode, up to 50 speakers) |
| Power Bank | Yes (USB-C) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | No |
| Weight | 9 lbs / 4.1 kg |
- Links
- Reviews, Comparisons and Sound Samples
- JOY‘s 3D Audio Show: B&W Zeppelin - audiophile sound quality test 🎧 More from Oluv’Sone →
- Oluv Patreon: B&W Zeppelin vs Earfun UBoom X (indoor+)
- Oluv Patreon: An evening with the “best portable speakers”?
- Joy & Oluv’Sone: Tribit Stormbox Blast vs Earfun UBoom X, a PROPER sound test 😎
- Joy & Oluv’Sone: B&O Beolit 20 vs Earfun UBoom X - everything fake?
- Joy & Oluv’Sone: 🎃🔥 UBoom X - Halloween Rock Special 🎸🤘
- JOY‘s 🎧3D🔈Audio-Show: JBL Charge 6, Xtreme 4 & Earfun UBoom X - taking sound to the top
- M1M Tech Channel: Partybox Killer? 2x Earfun UBoom X stärker als JBL Encore 2 ? More from M1MTechChannel →
- Mateusz Cholewa: EarFun UBOOM X Deep Bass 🆚 Tribit Stormbox Blast🎶Review👌 More from Mateusz Cholewa →
- Mateusz Cholewa: TRIBIT StormBox LAVA vs EarFun UBOOM X
- Joy & Oluv’Sone: $600 premium Bluetooth speaker vs $115 cheapo UBoom X
- Joy & Oluv’Sone: Tribit Stormbox Blast 2 - outdoor sound test
- Joy & Oluv’Sone: Tribit Stormbox Blast 2 - indoor sound test
- Joy & Oluv’Sone: Tribit Stormbox Blast 2 vs 2 Earfun UBoom X - outdoor test
- Joy & Oluv’Sone: JBL Partybox Encore vs Earfun UBoom X: outdoors
- Joy & Oluv’Sone: JBL Partybox Encore vs Earfun UBoom X: indoors
- Joy & Oluv’Sone: Soundcore Motion Boom Plus & Earfun UBoom X - sound test
- Joy & Oluv’Sone: Earfun UBoom X vs W-King D10 - same price, same sound?
- Joy & Oluv’Sone: Best portable speakers 2025 - get the best bang for your buck $$$
- Oluv Patreon: JBL Partybox 720 - first impressions
- Oluv Patreon: Harman Kardon go+play 3 vs Earfun UBoom X
- Oluv Patreon: Earfun UBoom X vs JBL Boombox 3 - outdoor test
- Oluv Patreon: Earfun UBoom X im Vergleich zum Teufel nochmal
- Oluv Patreon: Earfun UBoom X vs JBL Boombox 3 - outdoor
- Oluv Patreon: UBoom X - desktop mode demonstration
- Oluv Patreon: Earfun UBoom X - different firmware versions
- Oluv Patreon: UBoom X - final outdoor test
- Oluv Patreon: Tribit Stormbox Blast vs Earfun UBoom X - outdoor test
- Oluv Patreon: Earfun UBoom X - listening session
- Oluv Patreon: Earfun UBoom X vs JBL Partybox 100
- Oluv Patreon: Earfun UBoom X - final sound check
- Oluv Patreon: Earfun UBoom X - teaser 3
- Oluv Patreon: Earfun UBoom X - teaser 2
- Oluv Patreon: Earfun UBoom X - teaser 1
- Oluv Patreon: Marshall Middleton II - first impressions
- Oluv Patreon: JBL Authentics 300 - listening session
- Oluv Patreon: Zealot S89 vs Yeahbox Boom Max3 - indoor listening test
- Alan Ross Reviews: Earfun Uboom X Mini Boombox bluetooth speaker, a PROPER review 😝 More from alanrossreviews →
- JOY‘s 🎧3D🔈Audio-Show: JBL Boombox 4 vs Earfun UBoom X - sound test
- Josh’s Gadgets and More: Earfun Uboom X vs ZZA K8 sound comparison
- Joy & Oluv’Sone: J&O sEARius vs Earfun UBoom X and a bit of Bose
- Reddit Search for Earfun Uboom X Review
- Head-to-Head Comparisons
- Earfun Uboom X vs Tribit Stormbox Blast
- Earfun Uboom X vs Harman Kardon Go + Play 3
- Earfun Uboom X vs JBL Partybox Encore 2
- Earfun Uboom X vs JBL Partybox Encore Essential 2
- Earfun Uboom X vs JBL Partybox Encore
- Earfun Uboom X vs Harman Kardon Onyx Studio 9
- Earfun Uboom X vs Zealot ZE41
- Earfun Uboom X vs JBL Boombox 4
- See all 26 comparisons