Short answer: the Ultimate Ears Boom 4, though neither ranks well in its class. It ranks #113 of 175 medium speakers by sound quality (rated 2.9/5) at $129.99 and is still sold new; the Zealot S61 ranks #172 (rated 2.0/5) and is discontinued, so it is only an option used. Both are rated below 3.0/5 among the 175 medium speakers, and the EarFun Uboom L, ranked #2 at $49.79, is a better place to start if sound quality matters.
The Ultimate Ears Boom 4 is the better-sounding option. IP67 rated, floats, and finally charges via USB-C instead of the older Booms’ Micro-USB. It has an adjustable EQ, which the Zealot S61 lacks. It plays in stereo from a single unit, unlike the Zealot S61. The tradeoff: Not much improvement over the old ones.
The Zealot S61 is the longer-running pick. 20W output, IPX7 waterproof, exceptional 40-hour battery life, Bluetooth 5.2, TWS stereo pairing, compact 1.5 lbs (665 g) design, single full-range driver, built-in microphone, AUX input, USB-C charging. It is rated for 40 hours of battery against 15 for the Ultimate Ears Boom 4. It keeps a wired aux input, which the Ultimate Ears Boom 4 lacks. The catch: Sounds like a soup can, no bass at all.
Buy the Ultimate Ears Boom 4. It is rated higher for sound quality and still sold new, while the Zealot S61 is discontinued.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Specifications Side By Side
| Ultimate Ears Boom 4 | Zealot S61 | |
|---|---|---|
| Price | $129.99 | $20 Discontinued |
| Ranked | #113 of 175 in Medium Size Portable Bluetooth Speakers | #172 of 175 in Medium Size Portable Bluetooth Speakers |
| App | Yes | No |
| Battery Life | 15 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| IP Rating | IP67 | IPX7 |
| Power Input | USB-C | USB-C |
| Stereo | Yes | No (single full-range driver) |
| Omnidirectional | No | No |
| Weight | 1.4 lbs (620 g) | 1.5 lbs (665 g) |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 5.1 | 5.2 |
| Dimensions | 7.2” x 2.9” x 2.9” (184 x 73 x 73 mm) | 4.1” x 4.1” x 6.7” (103 x 103 x 170 mm) |
| Drivers | 2x 1.57” (40mm) active drivers + 2x 1.81” x 2.57” (46.1 x 65.2mm) passive radiators | 66mm full-range |
| TWS | Yes | Yes |
| EQ | Yes (via app) | No |
| Built-in Microphone | No | Yes |
| Power Bank | No | No |
| Aux Input | No | Yes |
| Maximum SPL | 85dBC (Manufacturer specified) | - |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC | SBC (inferred; additional codecs unverified) |
| Strap | Yes (built-in loop) | - |
| Amplifier Power | - | 20W |
Related Speaker Comparisons
How Ultimate Ears Boom 4 compares with other leading options:
- Ultimate Ears Boom 4 vs EarFun Uboom L
- Soundcore Motion 300 vs Ultimate Ears Boom 4
- Soundcore Motion+ vs Ultimate Ears Boom 4
- Soundcore Boost “upgraded” 2021 vs Ultimate Ears Boom 4
- Ultimate Ears Boom 4 vs Minirig 4
Prices on this page were last checked October 12, 2026 at 4:13 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
Ultimate Ears Boom 4: $129.99 Amazon $129.99 eBay
Older model: the Ultimate Ears Boom 3 (ranked lower, rated 2.9/5). See every Ultimate Ears Wonderboom, Boom and Megaboom generation.
Same family: the Ultimate Ears Wonderboom 4 (smaller model, ranked higher, rated 2.9/5) and the Ultimate Ears Megaboom 4 (larger model, ranked lower, rated 2.1/5).
Pros: IP67 rated, floats, and finally charges via USB-C instead of the older Booms’ Micro-USB. 15 hour battery. Customizable EQ and speaker-pairing via the UE app.
Cons: Not much improvement over the old ones. Weak bass extension and thuddy bass. Gets distorted above 90%
Full Ultimate Ears Boom 4 review and specifications →
| Released | Jun 2024 (2 years ago) |
|---|---|
| App | Yes |
| Aux Input | No |
| Battery Life | 15 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.1 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 7.2” x 2.9” x 2.9” (184 x 73 x 73 mm) |
| Drivers | 2x 1.57” (40mm) active drivers + 2x 1.81” x 2.57” (46.1 x 65.2mm) passive radiators |
| EQ | Yes (via app) |
| IP Rating | IP67 |
| Maximum SPL | 85dBC (Manufacturer specified) |
| Omnidirectional | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | Yes (built-in loop) |
| TWS | Yes |
| Weight | 1.4 lbs (620 g) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Ultimate Ears Boom 4 vs Ultimate Ears Boom 3
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom
- Ultimate Ears Boom 4 vs Klipsch Groove
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom 2
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom 3
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom 4
- Ultimate Ears Boom 4 vs DBSONO X-Blast F37
- Ultimate Ears Boom 4 vs Sony SRS-XE300
- See all 139 comparisons
Zealot S61: $20 Discontinued eBay
Pros: 20W output, IPX7 waterproof, exceptional 40-hour battery life, Bluetooth 5.2, TWS stereo pairing, compact 665g design, single full-range driver, built-in microphone, AUX input, USB-C charging
Cons: Sounds like a soup can, no bass at all. Weird frequency response all over. Discontinued and no longer sold new.
Full Zealot S61 review and specifications →
| Released | Feb 2022 (4 years ago) |
|---|---|
| Amplifier Power | 20W |
| App | No |
| Aux Input | Yes |
| Battery Life | 40 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) |
| Bluetooth Version | 5.2 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 4.1” x 4.1” x 6.7” (103 x 103 x 170 mm) |
| Drivers | 66mm full-range |
| EQ | No |
| IP Rating | IPX7 |
| Omnidirectional | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | No (single full-range driver) |
| TWS | Yes |
| Weight | 1.5 lbs (665 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons