Short answer: the Earfun Uboom L. It ranks #1 of 134 medium speakers at $50; the Bose Soundlink Flex 2nd gen ranks #33 and costs $129, so there is not much of a tradeoff to weigh.
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 Bose Soundlink Flex 2nd gen if the price matters more than the ranking. Buy the Earfun Uboom L if the ranking matters more than the price.
Specifications Side By Side
| Bose Soundlink Flex 2nd gen | Earfun Uboom L | |
|---|---|---|
| Price | $129.00 | $50 after coupon UBOOMLWC |
| Ranked | #33 of 134 in Medium Size Portable Bluetooth Speakers | #1 of 134 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 |
| TWS | Yes | Yes |
| Weight | 1.3 lbs / 586 g | 1.4 lbs / 650 g |
| Bluetooth Version | 5.3 | 5.0 |
| Dimensions | 7.9" x 3.6" x 2.1" (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 |
| Aux Latency | - | 216ms |
| Bass Extension (-10dB) | - | 56Hz |
| Bluetooth Latency | - | 400ms normal / 66ms low latency mode |
| Max Volume | - | 103dB |
| Power Bank | - | No |
| Output Power | - | 28W |
The Two Speakers In Full
Bose Soundlink Flex 2nd gen: $129.00 Amazon
Pros: Pretty much identical sounding to the 1st gen
Cons: Not stereo. Warm sounding with overly boosted bass which drowns out midrange detail. Self drains the battery about 10% a week.
| 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 |
| Dimensions | 7.9" x 3.6" x 2.1" (201 x 90 x 52 mm) |
| Drivers | 60mm full-range driver with passive radiators |
| EQ | Yes (3 band) |
| IP Rating | IP67 |
| Party Mode | Yes (Bose Party mode) |
| Power Input | USB-C |
| Stereo | No |
| TWS | Yes |
| Weight | 1.3 lbs / 586 g |
- Reviews, Comparisons and Sound Samples
- Joy & Oluv’Sone: Bose Soundlink Flex 2nd gen vs Flex
- 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!
- CEONTHEMAKING: Bose Soundlink Flex 2nd Gen VS Marshall Emberton III - What’s NEW??
- 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 JBL Charge 5 Wifi
- Bose Soundlink Flex 2nd gen vs Bogasing M4
- Bose Soundlink Flex 2nd gen vs Bogasing G4
- Bose Soundlink Flex 2nd gen vs Wisetiger P3
- Bose Soundlink Flex 2nd gen vs Miatone Boompro
- Bose Soundlink Flex 2nd gen vs JBL Charge 6
- Bose Soundlink Flex 2nd gen vs Sony ULT Field 3
- See all 14 comparisons
- Links
Earfun Uboom L: $50 after coupon UBOOMLWC Amazon Myearfun
Pros: Tuned by Oluv and he knocked it out of the park. The audiophile choice. Extremely neutral, possibly the best of any modern Bluetooth speaker slightly behind the Vifa Helsinki. This is the only speaker that sounds correct at every volume level. Other speakers will need a different EQ at each volume level. For maximum volume without distortion use max volume - 1 step for most songs. Oluv left another higher volume for songs that are quiet. Amazing sounding at low levels as it boosts bass and treble at low levels to account for the equal-loudness contour.
Cons: Latency is high (400ms) without turning on low latency mode (66ms) which doesn’t work when two speakers are TWS paired. Low latency mode can be turned on by pressing the Bluetooth button twice. If latency in TWS paired mode is a very important feature, like if you watch a lot of video, you may want to choose another speaker. The power button can sometimes get accidentally pressed when put in a bag. The aux input has quite a bit of latency and isn’t recommended for video use.
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.
| 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 |
| 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 |
| Max Volume | 103dB |
| Output Power | 28W |
| Party Mode | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 1.4 lbs / 650 g |
- Reviews, Comparisons and Sound Samples
- Joy & Oluv’Sone: Best portable speakers 2025 - get the best bang for your buck $$$
- 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…
- Techder Audios: EARFUN UBOOM L VS SOUNDCORE MOTION+
- Alan Ross Reviews: Earfun UBoom L Review Speaker tuned by a Geek vs Soundcore Motion Plus $100 dollar best portable?
- 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?🔝
- Joy & Oluv’Sone: JBL, Bose, B&O, Sonos, Earfun, SoundCore… which portable speaker sounds best?
- Head-to-Head Comparisons
- Links
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Product prices and availability were last checked August 9, 2026 at 6:57 AM UTC 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.