Bluetooth Speakers / Ultimate Ears WONDERBOOM 4 vs Bose SoundLink Flex (2nd Gen)
Ultimate Ears WONDERBOOM 4 vs Bose SoundLink Flex (2nd Gen)
Bose SoundLink Flex (2nd Gen)
The best-balanced small speaker here, and PositionIQ actually works.
Wins overall by 0.3 points
Quick Verdict
This is close. The Bose SoundLink Flex (2nd Gen) edges ahead by 0.3 points, but that margin is inside the noise — the Ultimate Ears WONDERBOOM 4 is a defensible pick on its own terms. Floats, survives a 5-foot drop, 360-degree sound — the poolside pick.
The Ultimate Ears WONDERBOOM 4 and Bose SoundLink Flex (2nd Gen) are both current-generation bluetooth Speaker models, and the Ultimate Ears WONDERBOOM 4 is $79 cheaper than the Bose SoundLink Flex (2nd Gen) ($79.99 vs $159). On Features, the Bose SoundLink Flex (2nd Gen) leads (6.5 vs 4.5/10) — app EQ, multi-speaker pairing, charge-out and extras. On Sound Quality, the Bose SoundLink Flex (2nd Gen) leads (8.0 vs 7.0/10) — tonal balance, clarity and detail. On Battery, the Ultimate Ears WONDERBOOM 4 leads (6.5 vs 5.5/10) — rated playtime and how it holds up at real listening volume. Overall, the Bose SoundLink Flex (2nd Gen) scores 7.2/10 across our 8 scoring categories versus 6.9/10 for the Ultimate Ears WONDERBOOM 4, though the gap is close enough that your specific use case should decide it. Below, we break down the full spec sheet, category-by-category scores, and exactly who should buy which one.
Side-by-Side Comparison
| Spec | Ultimate Ears WONDERBOOM 4 | Bose SoundLink Flex (2nd Gen) |
|---|---|---|
| Price | $79.99 | $159.00 |
| Release Year | 2024 | 2024 |
| Battery Life (hrs) | 14✓ | 12 |
| Water & Dust Rating | IP67 — dust and water, to 1m for 30 minutes | IP67 — dust and water |
| Floats | Yes | Yes |
| Power Output (W) | Ultimate Ears does not publish wattage; maximum SPL is quoted as 87dB | Bose does not publish power ratings for any SoundLink speaker |
| Weight (g) | 420✓ | 585 |
| Bluetooth | 5.2 | 5.3 |
| Drivers | 2x 40mm active drivers plus 2x 46.1 x 65.2mm passive radiators | Single full-range transducer with passive radiators; Bose does not publish driver dimensions |
| Stereo & Multi-Speaker Pairing | Double Up pairs two WONDERBOOM 4 units; it is not cross-compatible with earlier WONDERBOOMs, BOOM, MEGABOOM or HYPERBOOM | Two compatible Bose speakers can run in Stereo Mode or Party Mode; there is no large-scale chaining |
| Speakerphone | No | Yes |
| App EQ | No | Yes |
| Charges Your Phone | No | No |
| Warranty | 12 months | 12 months |
| Colors | Black, Blue, Pink, Grey | Black, Blue Dusk, Alpine Sage |
Category Scores
Sound Quality
The Bose SoundLink Flex (2nd Gen) leads clearly here, 8.0 against 7.0 — a 1.0-point margin on tonal balance, clarity and detail. If that is what you are buying for, the Ultimate Ears WONDERBOOM 4 does not close the gap elsewhere.
Bass
The Bose SoundLink Flex (2nd Gen) leads clearly here, 6.5 against 6.0 — a 0.5-point margin on low-end weight and extension for the size. If that is what you are buying for, the Ultimate Ears WONDERBOOM 4 does not close the gap elsewhere.
Battery
The Ultimate Ears WONDERBOOM 4 leads clearly here, 6.5 against 5.5 — a 1.0-point margin on rated playtime and how it holds up at real listening volume. If that is what you are buying for, the Bose SoundLink Flex (2nd Gen) does not close the gap elsewhere.
Durability
The Ultimate Ears WONDERBOOM 4 leads clearly here, 9.5 against 9.0 — a 0.5-point margin on IP rating, drop resistance and whether it floats. If that is what you are buying for, the Bose SoundLink Flex (2nd Gen) does not close the gap elsewhere.
Portability
The Ultimate Ears WONDERBOOM 4 and Bose SoundLink Flex (2nd Gen) are level here, at 8.5/10 each. weight, size and how easily it travels is not what separates these two — look to the categories where the scores diverge.
Loudness
The Bose SoundLink Flex (2nd Gen) leads clearly here, 6.5 against 6.0 — a 0.5-point margin on maximum usable volume before it strains. If that is what you are buying for, the Ultimate Ears WONDERBOOM 4 does not close the gap elsewhere.
Features
The Bose SoundLink Flex (2nd Gen) leads clearly here, 6.5 against 4.5 — a 2.0-point margin on app EQ, multi-speaker pairing, charge-out and extras. If that is what you are buying for, the Ultimate Ears WONDERBOOM 4 does not close the gap elsewhere.
Value
The Ultimate Ears WONDERBOOM 4 leads clearly here, 7.5 against 7.0 — a 0.5-point margin on performance and features relative to price. If that is what you are buying for, the Bose SoundLink Flex (2nd Gen) does not close the gap elsewhere.
Best For
Choose the Ultimate Ears WONDERBOOM 4 if…
- • Battery matters most to you — the Ultimate Ears WONDERBOOM 4 scores 6.5/10 here (rated playtime and how it holds up at real listening volume).
- • Durability matters most to you — the Ultimate Ears WONDERBOOM 4 scores 9.5/10 here (IP rating, drop resistance and whether it floats).
- • You want to spend less — it's $79 cheaper.
Choose the Bose SoundLink Flex (2nd Gen) if…
- • Features matters most to you — the Bose SoundLink Flex (2nd Gen) scores 6.5/10 here (app EQ, multi-speaker pairing, charge-out and extras).
- • Sound Quality matters most to you — the Bose SoundLink Flex (2nd Gen) scores 8.0/10 here (tonal balance, clarity and detail).
- • Bass matters most to you — the Bose SoundLink Flex (2nd Gen) scores 6.5/10 here (low-end weight and extension for the size).
- • Your main use case is home.
Pros & Cons
Ultimate Ears WONDERBOOM 4
Pros
- +It genuinely floats, which matters at a pool or on a boat
- +IP67 plus a 5-foot drop rating — the most rugged small speaker here
- +360-degree sound is more room-filling than a forward-firing design
- +Outdoor Boost is genuinely useful outside
Cons
- −No companion app and no EQ at all
- −No microphone, so it cannot take calls
- −Ultimate Ears publishes no power figure
- −Distorts noticeably when pushed loud
- −Cannot pair with any other Ultimate Ears speaker, only another WONDERBOOM 4
Bose SoundLink Flex (2nd Gen)
Pros
- +The best tonal balance of any small speaker here — Bose's core strength
- +PositionIQ genuinely works, retuning whether it is upright, flat or hanging
- +Floats, with a full IP67 rating
- +App EQ finally added this generation
Cons
- −12 hours is short next to the Marshall's 32 or the Tribit's 24
- −Bose publishes no wattage or driver specification at all
- −No USB charge-out
- −No aux input
- −List price has risen from $149 to $159
Shop by Need
FAQs
Is the Ultimate Ears WONDERBOOM 4 or Bose SoundLink Flex (2nd Gen) better overall?+
Based on our 8-category scoring, the Bose SoundLink Flex (2nd Gen) comes out ahead overall. See the full breakdown in the scores section above — the right pick still depends on which categories matter most for your use case.
Which is better for Features, the Ultimate Ears WONDERBOOM 4 or the Bose SoundLink Flex (2nd Gen)?+
The Bose SoundLink Flex (2nd Gen) scores higher on Features (6.5/10 vs 4.5/10) — app EQ, multi-speaker pairing, charge-out and extras.
Which is better for Sound Quality, the Ultimate Ears WONDERBOOM 4 or the Bose SoundLink Flex (2nd Gen)?+
The Bose SoundLink Flex (2nd Gen) scores higher on Sound Quality (8.0/10 vs 7.0/10) — tonal balance, clarity and detail.
Which is better for Battery, the Ultimate Ears WONDERBOOM 4 or the Bose SoundLink Flex (2nd Gen)?+
The Ultimate Ears WONDERBOOM 4 scores higher on Battery (6.5/10 vs 5.5/10) — rated playtime and how it holds up at real listening volume.
Which is better for Bass, the Ultimate Ears WONDERBOOM 4 or the Bose SoundLink Flex (2nd Gen)?+
The Bose SoundLink Flex (2nd Gen) scores higher on Bass (6.5/10 vs 6.0/10) — low-end weight and extension for the size.
Is the Ultimate Ears WONDERBOOM 4 worth the price difference over the Bose SoundLink Flex (2nd Gen)?+
The Ultimate Ears WONDERBOOM 4 is the cheaper option at $79.99 versus $159. Whether the pricier model is "worth it" depends on how much you value its lead in Features.
Which is better suited to my use case?+
The Ultimate Ears WONDERBOOM 4 is the better fit if you mainly care about poolside or outdoor. The Bose SoundLink Flex (2nd Gen) is the better fit for home.
What's the warranty on the Ultimate Ears WONDERBOOM 4 vs the Bose SoundLink Flex (2nd Gen)?+
The Ultimate Ears WONDERBOOM 4 ships with a 12-month warranty; the Bose SoundLink Flex (2nd Gen) ships with a 12-month warranty. Always confirm current terms on the manufacturer's site before buying.
Should I wait for the next model instead of buying either of these?+
If either model is more than two years old, a successor may be close — check the "Latest Model" link on each product page. Otherwise, both are current, well-supported options and there's no strong reason to wait.
Cheaper Option
JBL Go 5 — $49.95
Premium Option
Marshall Emberton III — $179.99
Specifications and prices for both products last verified . Scores are calculated from published specifications — see how we compare products.