Short answer: the Earfun Uboom L on sound, with a latency catch. It was tuned by Oluv and, the notes say, he knocked it out of the park, though latency is high at 400ms unless low latency mode drops it to 66ms, and that mode does not work when two speakers are TWS paired. The Bose Soundlink Flex 2nd gen sounds pretty much identical to the 1st gen but is not stereo.
The case for the Bose Soundlink Flex 2nd gen: Pretty much identical sounding to the 1st gen. The catch: Not stereo.
What the Earfun Uboom L gets right: Tuned by Oluv and he knocked it out of the park. The catch: Latency is high (400ms) without turning on low latency mode (66ms) which doesn’t work when two speakers are TWS paired.
Buy the Earfun Uboom L. It is rated higher for sound quality than the Bose Soundlink Flex 2nd gen and costs less, which settles it without a real tradeoff to make.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Specifications Side By Side
| Bose Soundlink Flex 2nd gen | Earfun Uboom L | |
|---|---|---|
| Price | $159.00 | $49.79 after coupon UBOOMLWC |
| Ranked | #35 of 142 in Medium Size Portable Bluetooth Speakers | #1 of 142 in Medium Size Portable Bluetooth Speakers |
| App | Yes | Yes (firmware >= 1.2.6) |
| Battery Life | 12 hours (Manufacturer specified) | 16 hours (Manufacturer specified) |
| Built-in Microphone | Yes | Yes |
| EQ | Yes (3 band) | Yes (10 band, firmware >= 1.2.6) |
| IP Rating | IP67 | IP67 |
| Party Mode | Yes (Bose Party mode) | No |
| Power Input | USB-C | USB-C |
| Stereo | No | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 1.3 lbs (586 g) | 1.4 lbs (650 g) |
| Bluetooth Version | 5.3 | 5.0 |
| Dimensions | 7.9" x 3.5" x 2" (201 x 90 x 52 mm) | 3.1" x 8.3" x 2.8" (78 x 210 x 72 mm) |
| Aux Input | No | Yes |
| Drivers | 60mm full-range driver with passive radiators | 2x 55mm drivers + 2x passive radiators |
| Bluetooth Codecs | SBC, AAC, aptX Adaptive | AAC, SBC |
| Digital Aux Input | No | No |
| Aux Latency | - | 216ms |
| Bass Extension (-10dB) | - | 56Hz |
| Bluetooth Latency | - | 400ms normal / 66ms low latency mode |
| Maximum SPL | - | 103dB (measured by Alan Ross Reviews) |
| Power Bank | - | No |
| Amplifier Power | - | 28W |
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- Earfun Uboom L vs Soundcore Motion 300
- Earfun Uboom L vs Soundcore Motion+
- Earfun Uboom L vs Minirig 4
- Earfun Uboom L vs B&O Beosound A1 2nd gen
- Earfun Uboom L vs JBL Charge 6
Prices on this page were last checked September 23, 2026 at 11:24 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
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 |
| 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 Soundcore Boom 3i
- Bose Soundlink Flex 2nd gen vs Soundcore Motion 100
- Bose Soundlink Flex 2nd gen vs JBL Charge 5
- See all 94 comparisons
Earfun Uboom L: $49.79 after coupon UBOOMLWC Amazon Myearfun eBay
Pros: One of the strongest small-speaker values for music: reviews praise clear vocals, a natural overall balance and a genuinely convincing stereo image when two are paired. IP67 protection, indoor/outdoor sound modes and Video Mode make it unusually adaptable; Video Mode substantially improves lip-sync for a single speaker. Measured bass extension of 56Hz (-10dB).
Cons: It cannot produce real low-bass rumble or fill a large, noisy space, and the top end loses some detail. Low-latency Video Mode disables stereo pairing, so a two-speaker setup is not a good movie system. Firmware and app behavior have also varied over the model’s long life, and the physical controls can be easy to trigger in a bag.
Setup: Try setting up the Earfun App (Android or iOS) to see if that works. If not, you’ll need to flash firmware 1.2.7 to work with the app and set with Oluv’s EQ in the Earfun app which sounds the best. The instructions say that you need a USB3 cable, but most USB2 cables work just fine, try the one included with your phone. Check the current firmware version by turning it on, then pressing the power and Bluetooth buttons at the same time. To flash, turn the speaker off then hold down the Bluetooth button while plugging in the cable. To flash on a mac, see these instructions. In TWS mode, long press the outdoor button for 2 seconds to change TWS to Party mode and back.
Full Earfun Uboom L review and specifications →
| Amplifier Power | 28W |
|---|---|
| App | Yes (firmware >= 1.2.6) |
| Aux Input | Yes |
| Aux Latency | 216ms |
| Bass Extension (-10dB) | 56Hz |
| Battery Life | 16 hours (Manufacturer specified) |
| Bluetooth Codecs | AAC, SBC |
| Bluetooth Latency | 400ms normal / 66ms low latency mode |
| Bluetooth Version | 5.0 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 3.1" x 8.3" x 2.8" (78 x 210 x 72 mm) |
| Drivers | 2x 55mm drivers + 2x passive radiators |
| EQ | Yes (10 band, firmware >= 1.2.6) |
| IP Rating | IP67 |
| Maximum SPL | 103dB (measured by Alan Ross Reviews) |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 1.4 lbs (650 g) |
- Links
- Reviews, Comparisons and Sound Samples
- Joy & Oluv’Sone: Best portable speakers 2025 - get the best bang for your buck $$$ More from Oluv’Sone →
- Oluv Patreon: SoundCore Boom 3i - first impressions & EQs
- Joy & Oluv’Sone: New Beats Pill 2024: sound demo
- CEONTHEMAKING: Earfun Uboom L - This Speaker Replaced My JBL Flip 6… More from CEONTHEMAKING →
- Techder Audios: EARFUN UBOOM L VS SOUNDCORE MOTION+ More from techderaudios →
- Alan Ross Reviews: Earfun UBoom L Review Speaker tuned by a Geek vs Soundcore Motion Plus $100 dollar best portable? More from alanrossreviews →
- Oluv Patreon: Soundcore Motion 300 = Bose Soundlink Flex = Earfun UBoom L?
- Jay’s Straight Up Reviews & More: Earfun UBoom L 💣(EQ2) 🆚 Tribit XSound Mega 🔥(XBass EQ)- Bluetooth Speaker Bedroom Bash. Who U Got?🔝 More from JaysStraightUpReviews →
- Joy & Oluv’Sone: JBL, Bose, B&O, Sonos, Earfun, SoundCore… which portable speaker sounds best?
- DIY Subwoofers - Uboom L Measurements and Review
- Head-to-Head Comparisons