These are not really the same size class, and that is the honest framing here. The Harman Kardon Luna ranks #26 of 179 medium speakers by sound quality at $290.99; the Sony ULT Field 5 ranks #59 of 120 large speakers by sound quality at $348.
The Harman Kardon Luna is the lighter choice. A fully waterproof speaker with fairly balanced, bass rich sound, a separate tweeter, and stereo pairing with a second unit. At 2.5 lbs (1.13 kg) it weighs much less than the Sony ULT Field 5 at 7.3 lbs (3.3 kg). The catch: Boosted bass, and less detailed than higher-ranked speakers.
The Sony ULT Field 5 is the longer-running option. A tough, waterproof party speaker with loud, bass focused output, an aux input, a power bank and a long battery. It is rated for 25 hours of battery against 12 for the Harman Kardon Luna. It supports LDAC Bluetooth, which the Harman Kardon Luna lacks. It keeps a wired aux input, which the Harman Kardon Luna lacks. Watch for: It prioritizes bass and loudness over fidelity: reviews find the upper mids and highs subdued, with limited stereo separation and soundstage depth.
Buy the Harman Kardon Luna at $290.99 if you want a medium speaker. Buy the Sony ULT Field 5 at $348 if you want a large speaker instead.
Want more options? Browse the full Portable Bluetooth rankings.
Prices on this page were last checked November 7, 2026 at 7:34 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
| Harman Kardon Luna | Sony ULT Field 5 | |
|---|---|---|
| Price | $290.99 | $348.00 |
| Ranked | #26 of 179 in Medium Size Portable Bluetooth Speakers | #59 of 120 in Large Size Portable Bluetooth Speakers |
| App | No | Yes |
| Aux Input | No | Yes |
| Bass Extension (-10dB) | 57Hz | - |
| Battery Life | 12 hours (Manufacturer specified) | 25 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC, AAC, LDAC |
| EQ | No | Yes (App + ULT button) |
| IP Rating | IP67 | IP67 |
| MicroSD Playback | No | - |
| Power Input | USB-C | USB-C |
| Stereo | No | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| USB Playback | Yes | - |
| Weight | 2.5 lbs (1.13 kg) | 7.3 lbs (3.3 kg) |
| Bluetooth Version | 5.3 | 5.3 |
| Dimensions | 8.3” x 3.1” x 3.1” (210 x 78 x 80 mm) | 12.6” x 5.7” x 4.9” (320 x 144 x 125 mm) |
| Drivers | 48mm x 90mm woofer, 20mm tweeter | 2x 46mm tweeters + 1x 79mm x 107mm woofer |
| Frequency Response | 60Hz - 20kHz (Manufacturer specified) | - |
| Amplifier Power | 40W | 27W |
| Digital Aux Input | No | No |
| Built-in Microphone | - | Yes |
| Party Mode | - | Yes (Party Connect up to 100 speakers) |
| Power Bank | - | Yes (USB-C) |
| Strap | - | Yes (detachable shoulder strap) |
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