Short answer: the Marshall Kilburn III for better sound quality, the Zealot S67 for the lower price. The Marshall Kilburn III ranks #41 of 97 large speakers, rated 3.8/5, at $379.99. The Zealot S67 ranks #96, rated 2.0/5, at $70.94, $309.05 cheaper.
The Marshall Kilburn III is the better-sounding, longer-running pick. Spacious soundstage with broad stereo dispersion from Marshall’s True Stereophonic multi-driver layout, delivering warm, room-filling sound with 45Hz bass extension. It is rated for 50 hours of battery against 20 for the Zealot S67. It supports AAC Bluetooth, which the Zealot S67 lacks. It links with other speakers (Auracast), which the Zealot S67 cannot. Watch for: Noticeable dips in the midrange compromise frequency response neutrality, making vocals and acoustic instruments sound somewhat recessed or muffled compared to more linear competitors like the JBL Xtreme 4 unless the bass dial is dialed back.
The Zealot S67 is the tougher option. It offers a lot of practical hardware for a 5.3 lbs (2.4 kg) budget speaker: IPX6 water resistance, USB-C charging, aux and microSD playback, speakerphone, a claimed 20-hour battery and TWS pairing for a second unit. It is rated IPX6 against IP54 for the Marshall Kilburn III. The tradeoff: Sound quality is the catch.
Buy the Marshall Kilburn III if sound quality is the priority over the price, or the Zealot S67 if the price is the priority over sound quality.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Marshall Kilburn III | Zealot S67 | |
|---|---|---|
| Price | $379.99 | $70.94 |
| Ranked | #41 of 97 in Large Size Portable Bluetooth Speakers | #96 of 97 in Large Size Portable Bluetooth Speakers |
| Amplifier Power | 50W | 60W |
| App | Yes | No |
| Aux Input | Yes | Yes |
| Bass Extension (-10dB) | 45Hz | - |
| Battery Life | 50 hours (Manufacturer specified) | 20 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC, AAC | SBC |
| Bluetooth Version | 5.3 | 5.2 |
| Built-in Microphone | No | Yes |
| Digital Aux Input | No | No |
| Dimensions | 10.7” x 5.9” x 6.7” (272 x 150 x 170 mm) | 11.6” x 4.8” x 5.2” (294 x 122 x 132 mm) |
| Drivers | 1x 4” woofer + 2x 2” full-range drivers | 60W: Dual drivers + passive radiator |
| EQ | Yes | No |
| Frequency Response | 45Hz - 20kHz | - |
| IP Rating | IP54 | IPX6 |
| Maximum SPL | 91dB | - |
| Omnidirectional | No | No |
| Party Mode | Yes (Auracast) | No |
| Power Bank | Yes | No |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Yes |
| Strap | Yes (built-in strap) | - |
| TWS | Yes | Yes |
| Weight | 6.3 lbs (2.85 kg) | 5.3 lbs (2.4 kg) |
| MicroSD Playback | - | Yes |
Related Speaker Comparisons
More worthwhile head-to-heads for Marshall Kilburn III:
- JBL Xtreme 5 vs Marshall Kilburn III
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- Brane X vs Marshall Kilburn III
- Soundcore Boom 2 vs Marshall Kilburn III
- Marshall Stockwell II vs Marshall Kilburn III
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 III: $379.99 Amazon eBay
Older model: the Marshall Kilburn II (ranked lower, rated 3.8/5).
Pros: Spacious soundstage with broad stereo dispersion from Marshall’s True Stereophonic multi-driver layout, delivering warm, room-filling sound with 45Hz bass extension. Independent physical bass and treble dials allow quick tonal adjustments on the fly, backed by app-based EQ and placement compensation. Battery life is outstanding at up to 50+ hours with USB-C power-bank charging, IP54 splash resistance, 3.5mm aux input, and Bluetooth 5.3 with Auracast broadcast support. Measured bass extension of 45Hz (-10dB).
Cons: Noticeable dips in the midrange compromise frequency response neutrality, making vocals and acoustic instruments sound somewhat recessed or muffled compared to more linear competitors like the JBL Xtreme 4 unless the bass dial is dialed back. Kilburn II retains slightly punchier perceived loudness at maximum volume due to a more aggressive V-shaped contour. At 2.85 kg with only IP54 splash resistance, it is heavy and cannot withstand water immersion. Lacks a built-in microphone and LDAC codec support.
Full Marshall Kilburn III review and specifications →
| Amplifier Power | 50W |
|---|---|
| App | Yes |
| Aux Input | Yes |
| Bass Extension (-10dB) | 45Hz |
| Battery Life | 50 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC, AAC |
| Bluetooth Version | 5.3 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 10.7” x 5.9” x 6.7” (272 x 150 x 170 mm) |
| Drivers | 1x 4” woofer + 2x 2” full-range drivers |
| EQ | Yes |
| Frequency Response | 45Hz - 20kHz |
| IP Rating | IP54 |
| Maximum SPL | 91dB |
| Omnidirectional | No |
| Party Mode | Yes (Auracast) |
| Power Bank | Yes |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | Yes (built-in strap) |
| TWS | Yes |
| Weight | 6.3 lbs (2.85 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Marshall Kilburn III vs Marshall Kilburn II
- Marshall Kilburn III vs JBL Xtreme 4
- Marshall Kilburn III vs Ultimate Ears Everboom
- Marshall Kilburn III vs W-King T9
- Marshall Kilburn III vs Marshall Middleton
- Marshall Kilburn III vs Devialet Mania
- Marshall Kilburn III vs Marshall Middleton II
- Marshall Kilburn III vs Sony ULT Field 5
- See all 31 comparisons
Zealot S67: $70.94 AliExpress eBay
Pros: It offers a lot of practical hardware for a 2.4kg budget speaker: IPX6 water resistance, USB-C charging, aux and microSD playback, speakerphone, a claimed 20-hour battery and TWS pairing for a second unit. The large enclosure and dual-driver/passive-radiator layout can provide useful party-level volume.
Cons: Sound quality is the catch. Independent reviewer comparisons report obvious distortion once volume rises past roughly halfway, little true deep bass, and a rolled-off, low-detail treble. There is no app or real EQ to correct that balance, so its long feature list does not make it a good pick for attentive music listening.
Full Zealot S67 review and specifications →
| Amplifier Power | 60W |
|---|---|
| App | No |
| Aux Input | Yes |
| Battery Life | 20 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.2 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 11.6” x 4.8” x 5.2” (294 x 122 x 132 mm) |
| Drivers | 60W: Dual drivers + passive radiator |
| EQ | No |
| IP Rating | IPX6 |
| MicroSD Playback | Yes |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 5.3 lbs (2.4 kg) |
- Links
- Reviews, Comparisons and Sound Samples
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