Short answer: the onn Portable FM Boombox. It ranks #23 of 78 large speakers by sound quality at $74.83; the Marshall Kilburn II ranks #36 and costs $219, so there is little reason to consider the other one.
What the Marshall Kilburn II offers: 20W Class D amp + dual 8W tweeters. 20+ hour battery with quick-charge (20 min charges 3 hours of play). Rugged design with leather handle and reinforced corners, IPX2 rated. Thrives with rock music. Bluetooth 5.0 with 30ft range. Watch for: Boosted upper bass, not very detailed, not as deep bass as competitors, upper mids peak. Very low IPX2 water rating. AC charging
What the onn Portable FM Boombox offers: Extremely good value. Reasonably deep bass, though not as deep as something like the JBL Xtreme 3, Soundcore Boom 2, or Tribit Stormbox Lava. IPX7 waterproof and floats. FM radio with 10 presets. 6 multicolor LED lighting effects. Can run on battery or corded power. Watch for: Reasonable frequency response, but not quite as smooth as some of the top-ranked speakers in this size. No custom EQ. Only available in the United States and Canada.
Buy the onn Portable FM Boombox. It ranks higher for sound quality than the Marshall Kilburn II and costs less, so there is no real case for the other one.
Water resistance is not close: the onn Portable FM Boombox is rated at IPX7 (brief submersion), well ahead of the Marshall Kilburn II at IPX2 (light drips).
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Marshall Kilburn II | onn Portable FM Boombox | |
|---|---|---|
| Price | $219.00 | $74.83 |
| Ranked | #36 of 78 in Large Size Portable Bluetooth Speakers | #23 of 78 in Large Size Portable Bluetooth Speakers |
| Aux Input | Yes | Yes |
| Bass Extension (-10dB) | ~58Hz | - |
| Battery Life | 20 hours (Manufacturer specified) | 16 hours (Manufacturer specified) |
| IP Rating | IPX2 | IPX7 |
| Weight | 5.5 lbs (2.49 kg) | 4.9 lbs (2.22 kg) |
| App | No | No |
| Bluetooth Codecs | SBC | SBC (inferred; additional codecs unverified) |
| Built-in Microphone | Yes | Yes |
| EQ | No | No |
| Party Mode | No | Yes (Party Sync, pairs with 1 other onn. speaker) |
| Power Bank | No | Yes (USB-A) |
| Power Input | USB-C | USB-C |
| Stereo | Yes | - |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Amplifier Power | 36W | 25W RMS (100W peak) |
| Dimensions | 9.6" x 6.4" x 5.5" (243 x 162 x 140 mm) | 13.8" x 5.9" x 7.7" (350 x 149 x 195 mm) |
| Drivers | 1x 4" (102mm) woofer + 2x 20mm dome tweeters | 2 speakers |
| Maximum SPL | 102dB (Manufacturer specified) | - |
| Digital Aux Input | No | No |
| FM Tuner | - | Yes (10 presets) |
| Removable Battery | - | No |
| Discontinued | - | No |
| Lights | - | Yes |
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How onn Portable FM Boombox compares with other leading options:
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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
Marshall Kilburn II: $219.00 Amazon eBay
Pros: 20W Class D amp + dual 8W tweeters. 20+ hour battery with quick-charge (20 min charges 3 hours of play). Rugged design with leather handle and reinforced corners, IPX2 rated. Thrives with rock music. Bluetooth 5.0 with 30ft range. Measured bass extension of ~58Hz (-10dB).
Cons: Boosted upper bass, not very detailed, not as deep bass as competitors, upper mids peak. Very low IPX2 water rating. AC charging
Full Marshall Kilburn II review and specifications →
| Amplifier Power | 36W |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | ~58Hz |
| Battery Life | 20 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 9.6" x 6.4" x 5.5" (243 x 162 x 140 mm) |
| Drivers | 1x 4" (102mm) woofer + 2x 20mm dome tweeters |
| EQ | No |
| IP Rating | IPX2 |
| Maximum SPL | 102dB (Manufacturer specified) |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 5.5 lbs (2.49 kg) |
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onn Portable FM Boombox: $74.83 Walmart eBay
Pros: Extremely good value. Reasonably deep bass, though not as deep as something like the JBL Xtreme 3, Soundcore Boom 2, or Tribit Stormbox Lava. IPX7 waterproof and floats. FM radio with 10 presets. 6 multicolor LED lighting effects. Can run on battery or corded power.
Cons: Reasonable frequency response, but not quite as smooth as some of the top-ranked speakers in this size. No custom EQ. Only available in the United States and Canada.
Full onn Portable FM Boombox review and specifications →
| Amplifier Power | 25W RMS (100W peak) |
|---|---|
| App | No |
| Aux Input | Yes |
| Battery Life | 16 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC (inferred; additional codecs unverified) |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 13.8" x 5.9" x 7.7" (350 x 149 x 195 mm) |
| Discontinued | No |
| Drivers | 2 speakers |
| EQ | No |
| FM Tuner | Yes (10 presets) |
| IP Rating | IPX7 |
| Lights | Yes |
| Omnidirectional | No |
| Party Mode | Yes (Party Sync, pairs with 1 other onn. speaker) |
| Power Bank | Yes (USB-A) |
| Power Input | USB-C |
| Removable Battery | No |
| TWS | Yes |
| Weight | 4.9 lbs (2.22 kg) |
- Links
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