Short answer: the Harman Kardon Luna 2 if sound quality matters most, the Ultimate Ears Boom 4 if price matters most. The Harman Kardon Luna 2 ranks #23 of 142 medium speakers at $199.95. The Ultimate Ears Boom 4 ranks #91 at $109.99, $89.96 cheaper.
What the Ultimate Ears Boom 4 offers: IP67 rated, floats, and finally charges via USB-C instead of the older Booms’ Micro-USB. 15 hour battery. Customizable EQ and speaker-pairing via the UE app. Watch for: Not much improvement over the old ones. Weak bass extension and thuddy bass. Gets distorted above 90%
What the Harman Kardon Luna 2 offers: Articulate, spacious midrange with precise imaging and instrument separation. Tight, well-controlled bass from the 62mm x 82mm woofer and passive radiator despite the compact body, and it stays cleaner at volume than pricier rivals like the Sonos Play. IP67 rated, and two units pair via AirTouch for true stereo sound. Watch for: Treble can sound bright and edgy, and it loses more output off-axis than some rivals. Some listeners hear mid-range rattling on certain tracks, similar to sibling JBL models. 12-hour battery life trails category leaders like the JBL Charge 6, which doubles it. Single unit is not stereo (1.1 driver layout).
Buy the Ultimate Ears Boom 4 if the price is the priority over sound quality, or the Harman Kardon Luna 2 if sound quality is the priority over the price.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Specifications Side By Side
| Ultimate Ears Boom 4 | Harman Kardon Luna 2 | |
|---|---|---|
| Price | $109.99 | $199.95 |
| Ranked | #91 of 142 in Medium Size Portable Bluetooth Speakers | #23 of 142 in Medium Size Portable Bluetooth Speakers |
| App | Yes | Yes |
| Battery Life | 15 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| IP Rating | IP67 | IP67 |
| Power Input | USB-C | USB-C |
| Stereo | Yes | No |
| Omnidirectional | No | No |
| Weight | 1.4 lbs (620 g) | 1.6 lbs (735 g) |
| Bluetooth Version | 5.1 | 5.4 |
| Dimensions | 7.2" x 2.9" x 2.9" (184 x 73 x 73 mm) | 8.5" x 3.3" x 3.2" (216 x 84 x 81 mm) |
| Drivers | 2x 1.57" (40mm) active drivers + 2x 1.81" x 2.57" (46.1 x 65.2mm) passive radiators | 62mm x 82mm woofer with passive radiator, 20mm tweeter |
| TWS | Yes | Yes |
| EQ | Yes (via app) | Yes (4 presets + custom) |
| Built-in Microphone | No | - |
| Power Bank | No | - |
| Aux Input | No | No |
| Maximum SPL | 85dBC (Manufacturer specified) | - |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC | SBC |
| MicroSD Playback | - | No |
| USB Playback | - | No |
| Frequency Response | - | 58Hz - 20kHz (-6dB) (Manufacturer specified) |
| Amplifier Power | - | 40W (25W woofer + 15W tweeter) |
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Prices on this page were last checked September 16, 2026 at 12:41 AM 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
Ultimate Ears Boom 4: $109.99 Amazon eBay
Pros: IP67 rated, floats, and finally charges via USB-C instead of the older Booms’ Micro-USB. 15 hour battery. Customizable EQ and speaker-pairing via the UE app.
Cons: Not much improvement over the old ones. Weak bass extension and thuddy bass. Gets distorted above 90%
Full Ultimate Ears Boom 4 review and specifications →
| App | Yes |
|---|---|
| Aux Input | No |
| Battery Life | 15 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.1 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 7.2" x 2.9" x 2.9" (184 x 73 x 73 mm) |
| Drivers | 2x 1.57" (40mm) active drivers + 2x 1.81" x 2.57" (46.1 x 65.2mm) passive radiators |
| EQ | Yes (via app) |
| IP Rating | IP67 |
| Maximum SPL | 85dBC (Manufacturer specified) |
| Omnidirectional | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 1.4 lbs (620 g) |
- Links
- Reviews, Comparisons and Sound Samples
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Harman Kardon Luna 2: $199.95 Amazon B&H Photo Video eBay
Pros: Articulate, spacious midrange with precise imaging and instrument separation. Tight, well-controlled bass from the 62mm x 82mm woofer and passive radiator despite the compact body, and it stays cleaner at volume than pricier rivals like the Sonos Play. IP67 rated, and two units pair via AirTouch for true stereo sound.
Cons: Treble can sound bright and edgy, and it loses more output off-axis than some rivals. Some listeners hear mid-range rattling on certain tracks, similar to sibling JBL models. 12-hour battery life trails category leaders like the JBL Charge 6, which doubles it. Single unit is not stereo (1.1 driver layout).
Full Harman Kardon Luna 2 review and specifications →
| Amplifier Power | 40W (25W woofer + 15W tweeter) |
|---|---|
| App | Yes |
| Aux Input | No |
| Battery Life | 12 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.4 |
| Digital Aux Input | No |
| Dimensions | 8.5" x 3.3" x 3.2" (216 x 84 x 81 mm) |
| Drivers | 62mm x 82mm woofer with passive radiator, 20mm tweeter |
| EQ | Yes (4 presets + custom) |
| Frequency Response | 58Hz - 20kHz (-6dB) (Manufacturer specified) |
| IP Rating | IP67 |
| MicroSD Playback | No |
| Omnidirectional | No |
| Power Input | USB-C |
| Stereo | No |
| TWS | Yes |
| USB Playback | No |
| Weight | 1.6 lbs (735 g) |
- Links
- Reviews, Comparisons and Sound Samples
- What Hi-Fi?: Harman Kardon Luna 2 review
- Joy & Oluv’Sone: Sonos Play & Harman Kardon Luna 2 - listening test More from Oluv’Sone →
- Mateusz Cholewa: Harman Kardon Luna 2 UNBOXING vs HK Luna Short Test More from Mateusz Cholewa →
- Storytripper HD: Harman Kardon Luna vs Luna 2 More from storytripperhd →
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