Short answer: the Zealot ZE21. It ranks #18 of 89 boombox speakers by sound quality (rated 4.0/5); the Teufel Boomster 4 ranks #44 (rated 3.4/5).
Why pick the Zealot ZE21: 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. The catch: 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.
What the Teufel Boomster 4 does well: Warmer and more open than the Boomster 2021 it replaces, with nicer, less harsh highs, a wide stereo image from its three-way layout (two 20mm tweeters, two 65mm midrange drivers and a 110mm woofer with passive radiators) and good detail. The tradeoff: Side by side with the Boomster 2021 the sound barely changed, and it has a little less deep bass.
Buy the Zealot ZE21. It is rated higher for sound quality than the Teufel Boomster 4.
Want more options? Browse the full Portable Bluetooth rankings.
Specifications Side By Side
| Zealot ZE21 | Teufel Boomster 4 | |
|---|---|---|
| Price | $187.15 | €249.99 |
| Ranked | #18 of 89 in Boombox Size Portable Bluetooth Speakers | #44 of 89 in Boombox Size Portable Bluetooth Speakers |
| App | No | No |
| Aux Input | Yes | Yes |
| Bass Extension (-10dB) | 36Hz | - |
| Battery Life | 40 hours (Manufacturer specified) | 23 hours (Manufacturer specified) |
| EQ | Yes (multiple modes) | Yes (treble control) |
| IP Rating | IPX6 | IPX5 |
| MicroSD Playback | Yes | - |
| Party Mode | Yes (PartyAdd up to 100 speakers) | - |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 20.4 lbs (9.27 kg) | 8.3 lbs (3.75 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | aptX HD, AAC, SBC |
| Power Bank | Yes (USB-A + USB-C) | No |
| USB Playback | Yes | - |
| Built-in Microphone | No | - |
| Amplifier Power | 250W | 42W RMS |
| Dimensions | 16.7” x 10.3” x 14.3” (424 x 262 x 363 mm) | 7.1”H x 14.6”W x 5.8”D (180 x 370 x 148 mm) |
| Drivers | 130W subwoofer + 2x 50mm woofers + passive radiators | 2x 20mm tweeters + 2x 65mm midrange drivers + 1x 110mm (4.3”) woofer, passive bass radiators |
| Maximum SPL | 116dB (Manufacturer specified) | - |
| Digital Aux Input | No | - |
| Bluetooth Version | 5.3 | 5.0 |
| FM Tuner | - | Yes (plus DAB+) |
| Strap | - | No |
Related Speaker Comparisons
How Zealot ZE21 compares with other leading options:
- 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 September 30, 2026 at 2:57 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: $187.15 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
- Jagist reviews: Jbl Boombox 4 Vs Zealot Ze21!!! More from Jagistreviews →
- Jagist reviews: Zealot Ze21 Vs Tribit Stormbox Blast 2!!!
- 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
Teufel Boomster 4: €249.99 Teufel eBay
Older models: the Teufel Boomster 2021 (ranked lower, rated 3.4/5) and the Teufel Boomster NG (2017) (ranked lower, rated 3.2/5).
Pros: Warmer and more open than the Boomster 2021 it replaces, with nicer, less harsh highs, a wide stereo image from its three-way layout (two 20mm tweeters, two 65mm midrange drivers and a 110mm woofer with passive radiators) and good detail. Its new treble control and remote let you tame the top end. DAB+ and FM radio, a claimed 23 hours of battery at medium volume, IPX5, Bluetooth 5.0 with AAC and aptX HD, multipoint, an aux input, USB-C charging and stereo pairing.
Cons: Side by side with the Boomster 2021 the sound barely changed, and it has a little less deep bass. Against the Harman Kardon Go + Play 3 it sounds sharper and thinner, with weaker bass and a less natural stereo image, and its bass drops off at full volume. At 3.75 kg it is heavy for its size, it has no power bank output, and IPX5 is a step down from the older model’s IPX7.
Full Teufel Boomster 4 review and specifications →
| Amplifier Power | 42W RMS |
|---|---|
| App | No |
| Aux Input | Yes |
| Battery Life | 23 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | aptX HD, AAC, SBC |
| Bluetooth Version | 5.0 |
| Dimensions | 7.1”H x 14.6”W x 5.8”D (180 x 370 x 148 mm) |
| Drivers | 2x 20mm tweeters + 2x 65mm midrange drivers + 1x 110mm (4.3”) woofer, passive bass radiators |
| EQ | Yes (treble control) |
| FM Tuner | Yes (plus DAB+) |
| IP Rating | IPX5 |
| Omnidirectional | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | No |
| TWS | Yes |
| Weight | 8.3 lbs (3.75 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Mateusz Cholewa: Nowy TEUFEL Boomster 4 UNBOXING vs Boomster 3 Review in subtitles More from Mateusz Cholewa →
- Mateusz Cholewa: TEUFEL Boomster 4 vs HK Go Plus Play 3 & Opinion in Subtitles
- Dominik Reviews: Teufel BOOMSTER 4 vs BOOMSTER 2021 - No difference? Sound Battle! More from Dominik Reviews →
- Dominik Reviews: Teufel BOOMSTER 4 vs JBL Xtreme 4 - Not great for the size? Sound Test
- Dominik Reviews: Teufel BOOMSTER 4 vs Earfun UBOOM X - BASS!! - Sound Test
- Dominik Reviews: Teufel BOOMSTER 4 vs Bugani Brief Pro - Cheaper and Better! Sound Test
- Head-to-Head Comparisons
- Teufel Boomster 4 vs Teufel Boomster 2021
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- Teufel Boomster 4 vs W-King X20
- Teufel Boomster 4 vs Soundcore Boom 2 Plus
- Teufel Boomster 4 vs Onn Medium Party Speaker Gen 2
- Teufel Boomster 4 vs Tribit Stormbox Blast 2
- Teufel Boomster 4 vs JBL Partybox On the Go
- Teufel Boomster 4 vs Bugani Brief Pro
- See all 26 comparisons