Short answer: the Ultimate Ears Boom 4 if sound quality matters most, the Zealot S61 if price matters most. The Ultimate Ears Boom 4 ranks #88 of 136 medium speakers at $105. The Zealot S61 ranks #134 at $20, $85 cheaper.
What the Ultimate Ears Boom 4 offers: 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. Watch for: Not much improvement over the old ones. Weak bass extension and thuddy bass. Gets distorted above 90%
What the Zealot S61 offers: 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 Watch for: Sounds like a soup can, no bass at all. Weird frequency response all over.
Buy the Ultimate Ears Boom 4 if sound quality is the priority over the price, or the Zealot S61 if the price is the priority over sound quality.
Skip the Zealot S61 if sound quality matters to you. It ranks near the bottom of the 136 medium speakers.
If battery life is a priority, the Zealot S61 is rated for 40 hours versus 15 hours for the Ultimate Ears Boom 4.
Specifications Side By Side
| Ultimate Ears Boom 4 | Zealot S61 | |
|---|---|---|
| Price | $105 | $20 |
| Ranked | #88 of 136 in Medium Size Portable Bluetooth Speakers | #134 of 136 in Medium Size Portable Bluetooth Speakers |
| App | Yes | - |
| Battery Life | 15 hours (Manufacturer specified) | 40 hours (Manufacturer specified) |
| IP Rating | IP67 | IPX7 |
| Power Input | USB-C | USB-C |
| Stereo | Yes | - |
| Omnidirectional | No | No |
| Weight | 1.4 lbs / 620 g | 1.5 lbs / 665 g |
| 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) | - |
| Built in Microphone | No | Yes |
| Power Bank | No | No |
| Aux Input | No | Yes |
| Max Volume | 85dBC | - |
| Digital Aux Input | No | No |
| Output Power | - | 20W |
Related Speaker Comparisons
A few more comparisons worth a look in the same class:
- JBL Flip 5 vs Altec Lansing Lifejacket 2/ Lifejacket 3
- Soundcore Motion 100 vs Ultimate Ears Wonderboom
- Soundcore 3/Soundcore Select 2 vs Ultimate Ears Wonderboom
- Bose SoundLink Color II vs Zealot S61
- Ultimate Ears Boom 4 vs Tribit Stormbox Mini
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
Ultimate Ears Boom 4: $105 Amazon eBay
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 →
| App | Yes |
|---|---|
| Aux Input | No |
| Battery Life | 15 hours (Manufacturer specified) |
| 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 |
| Max Volume | 85dBC |
| Omnidirectional | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| 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/Heritage 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 Sony SRS-XE300
- Ultimate Ears Boom 4 vs Tribit Stormbox
- See all 74 comparisons
Zealot S61: $20 Amazon Aliexpress 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.
Full Zealot S61 review and specifications →
| Aux Input | Yes |
|---|---|
| Battery Life | 40 hours (Manufacturer specified) |
| 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 |
| IP Rating | IPX7 |
| Omnidirectional | No |
| Output Power | 20W |
| Power Bank | No |
| Power Input | USB-C |
| TWS | Yes |
| Weight | 1.5 lbs / 665 g |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons