Short answer: the Soundcore Boom 3i. It ranks #29 of 145 medium portable speakers against the Flex 2nd gen’s #35, at essentially the same price, so there is little reason to pay the same money for the lower-ranked speaker.
The two take very different approaches to sound. The Flex 2nd gen’s own notes say it sounds nearly identical to the original Flex, warm with bass boosted enough to drown out midrange detail, and it is not stereo. It also self-drains about 10% of its battery a week when idle. The Boom 3i’s notes describe it as looking like a direct answer to the JBL Charge 5, with a similar warm, bass-forward tuning at better value, though it does not quite match the Charge 5 for loudness or balance. An early Boom 3i firmware version had some bass distortion that Soundcore addressed in an update through its app.
Everything else is close: neither speaker is stereo, and both lean into a warm, bass-heavy signature rather than a neutral one.
Buy the Soundcore Boom 3i for the higher-ranked sound at the same price, as long as you keep its firmware current.
Buy the Bose Soundlink Flex 2nd gen if you specifically want the Bose ecosystem or form factor and can live with the battery drain and a bass-heavy tuning that overshadows midrange detail.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Bose Soundlink Flex 2nd gen | Soundcore Boom 3i | |
|---|---|---|
| Price | $159.00 | $118.99 |
| Ranked | #35 of 145 in Medium Size Portable Bluetooth Speakers | #29 of 145 in Medium Size Portable Bluetooth Speakers |
| App | Yes | Yes |
| Battery Life | 12 hours (Manufacturer specified) | 16 hours (Manufacturer specified) |
| Built-in Microphone | Yes | Yes |
| EQ | Yes (3 band) | Yes |
| IP Rating | IP67 | IP68 |
| Party Mode | Yes (Bose Party mode) | No |
| Power Input | USB-C | USB-C |
| Stereo | No | No |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 1.3 lbs (586 g) | 1.7 lbs (783 g) |
| Bluetooth Version | 5.3 | 5.3 |
| Dimensions | 7.9” x 3.5” x 2” (201 x 90 x 52 mm) | 8.3” x 3.3” x 3.1” (210 x 85 x 78.5 mm) |
| Aux Input | No | No |
| Drivers | 60mm full-range driver with passive radiators | 94mm woofer + tweeter |
| Bluetooth Codecs | SBC, AAC, aptX Adaptive | SBC, AAC |
| Digital Aux Input | No | No |
| Strap | Yes (built-in loop) | Yes (detachable strap) |
| Bass Extension (-10dB) | - | 56Hz |
| Amplifier Power | - | 50W |
| Lights | - | Yes |
Related Speaker Comparisons
How Soundcore Boom 3i compares with other leading options:
- Soundcore Boom 3i vs Earfun Uboom L
- Soundcore Motion 300 vs Soundcore Boom 3i
- Soundcore Motion+ vs Soundcore Boom 3i
- Soundcore Boost “upgraded” 2021 vs Soundcore Boom 3i
- Soundcore Boom 3i vs Minirig 4
Prices on this page were last checked September 26, 2026 at 11:14 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
Bose Soundlink Flex 2nd gen: $159.00 Amazon eBay
Older model: the Bose Soundlink Flex (ranked lower, rated 3.8/5).
Pros: A very portable 586g, IP67-rated speaker with a clear, well-balanced midrange that keeps voices and instruments intelligible. The second generation adds a Bose app with 3-band EQ, better-placed controls and stereo pairing with another Bose Soundlink Flex 2nd gen. It supports AAC and aptX Adaptive in addition to SBC, making it a stronger wireless option than most small rivals.
Cons: One Flex remains mono and cannot deliver genuine low-bass rumble; RTINGS also found the elevated treble can turn hi-hats and other high-frequency detail piercing. The claimed battery life is only 12 hours, and some owners report accelerated standby drain after firmware updates. It is expensive for its size, so the added app and codec support, not a transformational sound upgrade over the original, are the main reasons to choose it.
Full Bose Soundlink Flex 2nd gen review and specifications →
| App | Yes |
|---|---|
| Aux Input | No |
| Battery Life | 12 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, AAC, aptX Adaptive |
| Bluetooth Version | 5.3 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 7.9” x 3.5” x 2” (201 x 90 x 52 mm) |
| Drivers | 60mm full-range driver with passive radiators |
| EQ | Yes (3 band) |
| IP Rating | IP67 |
| Omnidirectional | No |
| Party Mode | Yes (Bose Party mode) |
| Power Input | USB-C |
| Stereo | No |
| Strap | Yes (built-in loop) |
| TWS | Yes |
| Weight | 1.3 lbs (586 g) |
- Links
- Reviews, Comparisons and Sound Samples
- Joy & Oluv’Sone: Bose Soundlink Flex 2nd gen vs Flex More from Oluv’Sone →
- Oluv Patreon: Bose Soundlink Flex 2nd gen - sound demo
- Tô Thái Trí Hùng: Unbox & Sound Test - Bose Soundlink Flex 2
- Joy & Oluv’Sone: Bose Soundlink Flex 2nd gen & Soundcore Motion 300 sound test
- Alan Ross: Hall of Fame classic vs latest Bose tech! More from alanrossreviews →
- CEONTHEMAKING: Bose Soundlink Flex 2nd Gen VS Marshall Emberton III - What’s NEW?? More from CEONTHEMAKING →
- Alan Ross - The Anti Shill!: Small speaker, mighty sound, The Flex gen 2 shatters physics!
- Head-to-Head Comparisons
- Bose Soundlink Flex 2nd gen vs Bose Soundlink Flex
- Bose Soundlink Flex 2nd gen vs Tribit Xsound Plus 2
- Bose Soundlink Flex 2nd gen vs JBL Charge Essential 2
- Bose Soundlink Flex 2nd gen vs Teufel Rockster XS
- Bose Soundlink Flex 2nd gen vs Huawei Sound Joy
- Bose Soundlink Flex 2nd gen vs Cleer Audio Scene
- Bose Soundlink Flex 2nd gen vs JBL Charge Essential 3 SE
- Bose Soundlink Flex 2nd gen vs Earfun Uboom Slim
- See all 121 comparisons
Soundcore Boom 3i: $118.99 Amazon B&H Photo Video eBay
Pros: Looks to be designed as a direct competitor to the Charge 5 with a very similar sound profile, warm tuned with boosted bass. Better value for the money than the Charge 5. Measured bass extension of 56Hz (-10dB).
Cons: Not quite as good as a Charge 5, doesn’t go quite as loud or sound quite as balanced, but very very close. An earlier firmware version had some bass distortion, update your firmware in the Soundcore App
Full Soundcore Boom 3i review and specifications →
| Amplifier Power | 50W |
|---|---|
| App | Yes |
| Aux Input | No |
| Bass Extension (-10dB) | 56Hz |
| Battery Life | 16 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, AAC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 8.3” x 3.3” x 3.1” (210 x 85 x 78.5 mm) |
| Drivers | 94mm woofer + tweeter |
| EQ | Yes |
| IP Rating | IP68 |
| Lights | Yes |
| Omnidirectional | No |
| Party Mode | No |
| Power Input | USB-C |
| Stereo | No |
| Strap | Yes (detachable strap) |
| TWS | Yes |
| Weight | 1.7 lbs (783 g) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Soundcore Boom 3i vs JBL Charge 5
- Soundcore Boom 3i vs JBL Charge 5 Wifi
- Soundcore Boom 3i vs Cleer Audio Scene
- Soundcore Boom 3i vs Teufel Rockster XS
- Soundcore Boom 3i vs Bogasing G4
- Soundcore Boom 3i vs Tribit Xsound Plus 2
- Soundcore Boom 3i vs Harman Kardon Luna
- Soundcore Boom 3i vs Harman Kardon Luna 2
- See all 117 comparisons