Short answer: the B&O Beolit 20. It ranks #48 of 112 boombox speakers by sound quality (rated 3.4/5) at $749 and is still sold new; the Diamondboxx M3 ranks #76 (rated 2.8/5) and is discontinued, so it is only an option used.
The Diamondboxx M3 is the longer-running option. A compact, very loud boombox with a powerful amplifier and a choice of large battery packs. It is rated for 40 hours of battery against 8 for the B&O Beolit 20. It plays in stereo from a single unit, unlike the B&O Beolit 20. Watch for: Despite its output, bass does not reach as deep as the best large portables and can distort when pushed hard.
The B&O Beolit 20 is the better-sounding, lighter pick. A premium designer portable with 360 degree sound and a top that doubles as a wireless phone charger. At 6 lbs (2.7 kg) it weighs much less than the Diamondboxx M3 at 11 lbs (5 kg). It is rated IPX4, while the Diamondboxx M3 has no water resistance. It has an adjustable EQ, which the Diamondboxx M3 lacks.
Buy the B&O Beolit 20. It is rated higher for sound quality; the Diamondboxx M3 is no longer sold new.
Want more options? Browse the full Portable Bluetooth rankings.
A compact, very loud boombox with a powerful amplifier and a choice of large battery packs.
A premium designer portable with 360 degree sound and a top that doubles as a wireless phone charger.
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Specifications Side By Side
| Diamondboxx M3 | B&O Beolit 20 | |
|---|---|---|
| Price | $700 Discontinued | $749.00 |
| Ranked | #76 of 112 in Boombox Size Portable Bluetooth Speakers | #48 of 112 in Boombox Size Portable Bluetooth Speakers |
| Bluetooth Version | 5.0 | 4.2 |
| Aux Input | Yes | Yes |
| Battery Life | 40 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| IP Rating | None | IPX4 |
| Stereo | Yes | No |
| Omnidirectional | No | Yes |
| Weight | 11 lbs (5 kg) | 6 lbs (2.7 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| App | No | Yes (Bang & Olufsen app) |
| EQ | No | Yes (App EQ) |
| TWS | Yes | Yes |
| Party Mode | No | No |
| Power Bank | No | Yes (USB-C) |
| USB Playback | No | No |
| Built-in Microphone | No | Yes |
| Power Input | USB-C | USB-C |
| FM Tuner | No | - |
| Amplifier Power | 200W RMS / 400W peak | 240W peak |
| Dimensions | 14.7” x 9” x 8” (373.4 x 228.6 x 203.2 mm) | 5.3” x 9.1” x 7.4” (135 x 230 x 189 mm) |
| Drivers | 3” woofer + tweeter array | 2x 30mm tweeters + 2x 40mm mid-range + 1x 60mm woofer + dual passive radiators |
| Digital Aux Input | No | No |
| Bass Extension (-10dB) | - | 45Hz |
| Maximum SPL | - | 93dB (Manufacturer specified) |
| Strap | - | Yes (built-in strap) |
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