Short answer: the Luna if balance matters, the Flex 2nd gen if price does. The Luna ranks #35 of 145 medium speakers against the Flex 2nd gen’s #24, for $131.99 more.
Neither speaker is neutral, but the Luna keeps its bass in check better. Its pros describe it as pretty balanced besides the boosted bass, while the Flex 2nd gen’s cons go further: warm sounding with overly boosted bass that drowns out midrange detail. Both measure mono rather than stereo, and the Luna’s cons note its own bass boost still leaves it less detailed than higher ranked speakers in the class.
The Flex 2nd gen has one known reliability quirk. Its cons note it self-drains the battery about 10% a week, something to plan around if you store it between uses. Its pros note it sounds pretty much identical to the original Flex, so if you already own that model this is not a sound upgrade.
What the Flex 2nd gen adds that the Luna lacks:
- An app with a 3-band EQ, versus no app or EQ on the Luna at all.
- Bose Party Mode for linking multiple Bose speakers.
- aptX Adaptive codec support and a built-in microphone, both missing on the Luna.
What the Luna adds: USB playback and a measured 57Hz bass extension, giving a documented number where the Flex 2nd gen has none listed.
Buy the Luna if you want the more balanced sound of the two and don’t mind going without an app or EQ.
Buy the Flex 2nd gen if budget is the priority, or if you want app-based EQ control and Bose Party Mode, and can tolerate a bass-heavy signature and the battery’s self-drain.
Want more options? Browse the full Portable Bluetooth rankings.
Specifications Side By Side
| Bose Soundlink Flex 2nd gen | Harman Kardon Luna | |
|---|---|---|
| Price | $159.00 | $290.99 |
| Ranked | #35 of 145 in Medium Size Portable Bluetooth Speakers | #24 of 145 in Medium Size Portable Bluetooth Speakers |
| App | Yes | No |
| Battery Life | 12 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| Built-in Microphone | Yes | - |
| EQ | Yes (3 band) | No |
| IP Rating | IP67 | IP67 |
| Party Mode | Yes (Bose Party mode) | - |
| Power Input | USB-C | USB-C |
| Stereo | No | No |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 1.3 lbs (586 g) | 2.5 lbs (1.13 kg) |
| Bluetooth Version | 5.3 | 5.3 |
| Dimensions | 7.9” x 3.5” x 2” (201 x 90 x 52 mm) | 8.3” x 3.1” x 3.1” (210 x 78 x 80 mm) |
| Aux Input | No | No |
| Drivers | 60mm full-range driver with passive radiators | 48mm x 90mm woofer, 20mm tweeter |
| Bluetooth Codecs | SBC, AAC, aptX Adaptive | SBC |
| Digital Aux Input | No | No |
| Strap | Yes (built-in loop) | - |
| Bass Extension (-10dB) | - | 57Hz |
| MicroSD Playback | - | No |
| USB Playback | - | Yes |
| Frequency Response | - | 60Hz - 20kHz (Manufacturer specified) |
| Amplifier Power | - | 40W |
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- Harman Kardon Luna 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!
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Harman Kardon Luna: $290.99 Amazon eBay
Newer model: the Harman Kardon Luna 2, ranked higher, rated 4.1/5.
Pros: Harman Kardon Luna uses 48mm x 90mm woofer, 20mm tweeter. Its 1.13 kg, claimed 12 hours (Manufacturer specified) battery life, IP67 protection and mono playback make it a practical option for its intended room or portable use. The sound is fairly balanced apart from the boosted bass. Measured bass extension of 57Hz (-10dB).
Cons: Bass is limited by its 57Hz specification. There is no companion app. No EQ adjustment. Boosted bass, and less detailed than higher-ranked speakers.
Full Harman Kardon Luna review and specifications →
| Amplifier Power | 40W |
|---|---|
| App | No |
| Aux Input | No |
| Bass Extension (-10dB) | 57Hz |
| Battery Life | 12 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Digital Aux Input | No |
| Dimensions | 8.3” x 3.1” x 3.1” (210 x 78 x 80 mm) |
| Drivers | 48mm x 90mm woofer, 20mm tweeter |
| EQ | No |
| Frequency Response | 60Hz - 20kHz (Manufacturer specified) |
| IP Rating | IP67 |
| MicroSD Playback | No |
| Omnidirectional | No |
| Power Input | USB-C |
| Stereo | No |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 2.5 lbs (1.13 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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