These are not really the same size class, and that is the honest framing here. The Harman Kardon Onyx Studio 9 ranks #15 of 113 boombox speakers by sound quality at $184.99; the Sony ULT Field 5 ranks #59 of 120 large speakers by sound quality at $348.
Why pick the Harman Kardon Onyx Studio 9: An elegant living room portable with balanced, smooth, non-fatiguing sound, app EQ, and stereo pairing for music lovers. The catch: It has no water resistance, aux input or USB playback, and its eight-hour claimed battery life is short for an outdoor portable.
The Sony ULT Field 5 is the longer-running, lighter choice. 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 8 for the Harman Kardon Onyx Studio 9. At 7.3 lbs (3.3 kg) it weighs noticeably less than the Harman Kardon Onyx Studio 9 at 9.3 lbs (4.2 kg). It is rated IP67, while the Harman Kardon Onyx Studio 9 has no water resistance. The catch: 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 Onyx Studio 9 ($184.99) for a boombox speaker; the Sony ULT Field 5 ($348) suits a large speaker instead.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
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 Onyx Studio 9 | Sony ULT Field 5 | |
|---|---|---|
| Price | $184.99 | $348.00 |
| Ranked | #15 of 113 in Boombox Size Portable Bluetooth Speakers | #59 of 120 in Large Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | 41Hz | - |
| Maximum SPL | 101dB (measured by Alan Ross Reviews) | - |
| IP Rating | None | IP67 |
| Power Input | AC Power Cable (2-Prong) | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 9.3 lbs (4.2 kg) | 7.3 lbs (3.3 kg) |
| App | Yes (Harman Kardon One app) | Yes |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC, AAC, LDAC |
| EQ | Yes (App EQ) | Yes (App + ULT button) |
| Party Mode | Yes (Auracast) | Yes (Party Connect up to 100 speakers) |
| USB Playback | No | - |
| Bluetooth Version | 5.3 | 5.3 |
| Battery Life | 8 hours (Manufacturer specified) | 25 hours (Manufacturer specified) |
| Amplifier Power | 50W RMS | 27W |
| Dimensions | 11.4” x 11.3” x 5.1” (289.2 x 287.5 x 130 mm) | 12.6” x 5.7” x 4.9” (320 x 144 x 125 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters | 2x 46mm tweeters + 1x 79mm x 107mm woofer |
| Digital Aux Input | No | No |
| Aux Input | No | Yes |
| Strap | No | Yes (detachable shoulder strap) |
| Built-in Microphone | - | Yes |
| Power Bank | - | Yes (USB-C) |
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