Short answer: the Harman Kardon Luna 2. It ranks #25 of 177 medium speakers by sound quality, rated 4.1/5, at $199.95. The Soundcore Boom 3i ranks #31, rated 4.0/5, at $118.99, $80.96 cheaper, not enough of a saving to outweigh the sound-quality gap.
The Soundcore Boom 3i is the longer-running option. A warm, punchy waterproof speaker that sounds great and is a strong value. It is rated for 16 hours of battery against 12 for the Harman Kardon Luna 2. It supports AAC Bluetooth, which the Harman Kardon Luna 2 lacks. The catch: Not quite as good as a JBL Charge 5, doesn’t go quite as loud or sound quite as balanced, but very very close.
Why pick the Harman Kardon Luna 2: A stylish waterproof speaker with clear, spacious mids, tight bass that stays clean at volume, and stereo pairing with a second unit. Watch for: Treble can sound bright and edgy, and it loses more output off-axis than some rivals.
Buy the Harman Kardon Luna 2. It is rated higher for sound quality, and the $80.96 you would save on the Soundcore Boom 3i does not close the gap.
Want more options? Browse the full Portable Bluetooth rankings.
A warm, punchy waterproof speaker that sounds great and is a strong value.
A stylish waterproof speaker with clear, spacious mids, tight bass that stays clean at volume, and stereo pairing with a second unit.
Prices on this page were last checked October 31, 2026 at 7:11 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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Specifications Side By Side
| Soundcore Boom 3i | Harman Kardon Luna 2 | |
|---|---|---|
| Price | $118.99 | $199.95 |
| Ranked | #31 of 177 in Medium Size Portable Bluetooth Speakers | #25 of 177 in Medium Size Portable Bluetooth Speakers |
| App | Yes | Yes |
| Aux Input | No | No |
| Bass Extension (-10dB) | 56Hz | - |
| Battery Life | 16 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| EQ | Yes | Yes (4 presets + custom) |
| IP Rating | IP68 | IP67 |
| Party Mode | No | - |
| Power Input | USB-C | USB-C |
| Stereo | No | No |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 5.3 | 5.4 |
| Dimensions | 8.3” x 3.3” x 3.1” (210 x 85 x 78.5 mm) | 8.5” x 3.3” x 3.2” (216 x 84 x 81 mm) |
| Drivers | 94mm woofer + tweeter | 62mm x 82mm woofer with passive radiator, 20mm tweeter |
| Weight | 1.7 lbs (783 g) | 1.6 lbs (735 g) |
| Amplifier Power | 50W | 40W (25W woofer + 15W tweeter) |
| Bluetooth Codecs | SBC, AAC | SBC |
| Built-in Microphone | Yes | - |
| Digital Aux Input | No | No |
| Lights | Yes | - |
| Strap | Yes (detachable strap) | No |
| MicroSD Playback | - | No |
| USB Playback | - | No |
| Frequency Response | - | 58Hz - 20kHz (-6dB) (Manufacturer specified) |
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