Short answer: the Marshall Kilburn II. Both are rated 3.8/5 for sound quality (#39 and #40 of 93 large speakers), and the Marshall Kilburn II costs $279 against $309.95 for the JBL Xtreme 4, and with sound quality even, the cheaper one is the better buy.
What the JBL Xtreme 4 offers: Removable battery. Watch for: High priced.
Buy the Marshall Kilburn II. Both are rated the same for sound quality, and it costs $30.95 less than the JBL Xtreme 4.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Specifications Side By Side
| Marshall Kilburn II | JBL Xtreme 4 | |
|---|---|---|
| Price | $279.00 | $309.95 |
| Ranked | #39 of 93 in Large Size Portable Bluetooth Speakers | #40 of 93 in Large Size Portable Bluetooth Speakers |
| Aux Input | Yes | No |
| Bass Extension (-10dB) | ~58Hz | - |
| Battery Life | 20 hours (Manufacturer specified) | 24 hours (Manufacturer specified) |
| IP Rating | IPX2 | IP67 |
| Weight | 5.5 lbs (2.49 kg) | 4.6 lbs (2.1 kg) |
| App | No | Yes |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| Built-in Microphone | Yes | Yes |
| EQ | No | Yes (5 band) |
| Party Mode | No | Yes (Auracast) |
| Power Bank | No | Yes (USB-C) |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Amplifier Power | 36W | 100W |
| Dimensions | 9.6” x 6.4” x 5.5” (243 x 162 x 140 mm) | 11.7” x 5.9” x 5.6” (297 x 149 x 141 mm) |
| Drivers | 1x 4” (102mm) woofer + 2x 20mm dome tweeters | 2x 70mm woofers, 2x 19mm tweeters + 2x passive radiators |
| Maximum SPL | 102dB (Manufacturer specified) | 106dB (measured by Alan Ross Reviews) |
| Digital Aux Input | No | No |
| Bluetooth Version | 5.0 | 5.3 |
| Strap | Yes (built-in strap) | Yes (detachable shoulder strap) |
| Bluetooth Latency | - | 220ms |
| Removable Battery | - | Yes |
| Frequency Response | - | 44Hz - 20kHz (Manufacturer specified) |
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Prices on this page were last checked October 2, 2026 at 10:18 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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The Two Speakers In Full
Marshall Kilburn II: $279.00 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 | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.0 |
| 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 |
| Strap | Yes (built-in strap) |
| TWS | Yes |
| Weight | 5.5 lbs (2.49 kg) |
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JBL Xtreme 4: $309.95 Amazon B&H Photo Video eBay
Newer model: the JBL Xtreme 5, ranked higher, rated 4.6/5.
Pros: A rugged 2.1kg portable with IP67 protection, a replaceable battery, USB-C power-bank output, Auracast, stereo pairing and a useful 5-band app EQ. Independent reviews find the midrange detailed and the sound clear, punchy and refined for outdoor use; it also reaches a strong 106dB maximum level and has excellent real-world battery life.
Cons: It cannot produce the deep rumble of a larger speaker, and bass compression increases near maximum volume. The front-facing layout has only modest off-axis consistency, Bluetooth latency is high for video, and the default balance benefits from EQ adjustment. There is no aux input, so wired sources are not supported. Out of the box it leans bass-boosted, with a dip between the upper bass and midrange that EQ cannot fix, and it pushes the upper mids and treble at high volume. It is also expensive.
Full JBL Xtreme 4 review and specifications →
| Amplifier Power | 100W |
|---|---|
| App | Yes |
| Aux Input | No |
| Battery Life | 24 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Latency | 220ms |
| Bluetooth Version | 5.3 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 11.7” x 5.9” x 5.6” (297 x 149 x 141 mm) |
| Drivers | 2x 70mm woofers, 2x 19mm tweeters + 2x passive radiators |
| EQ | Yes (5 band) |
| Frequency Response | 44Hz - 20kHz (Manufacturer specified) |
| IP Rating | IP67 |
| Maximum SPL | 106dB (measured by Alan Ross Reviews) |
| Omnidirectional | No |
| Party Mode | Yes (Auracast) |
| Power Bank | Yes (USB-C) |
| Power Input | USB-C |
| Removable Battery | Yes |
| Stereo | Yes |
| Strap | Yes (detachable shoulder strap) |
| TWS | Yes |
| Weight | 4.6 lbs (2.1 kg) |
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