Different classes, so treat this as a step-up-or-not question rather than a head-to-head. The JBL Flip 6 ranks #13 of 173 medium speakers by sound quality at $79.95; the Zealot S51 Pro costs $39.97.
The JBL Flip 6 is the lighter choice. A very neutral speaker, very small, almost pocket size, a huge sound quality leap over the JBL Flip 5. At 1.2 lbs (544 g) it weighs noticeably less than the Zealot S51 Pro at 1.5 lbs (703 g). The catch: Some slight upper mids emphasis.
The Zealot S51 Pro is the longer-running pick. The S51 Pro pairs a 40W amplifier (60W peak) with two 57mm drivers and two passive radiators in a 1.5 lbs (703 g), 86 x 88 x 200mm cylinder, giving it more low-frequency hardware than most cheap portables. It is rated for 20 hours of battery against 12 for the JBL Flip 6. It keeps a wired aux input, which the JBL Flip 6 lacks. It plays in stereo from a single unit, unlike the JBL Flip 6. The catch: No independent measurement of frequency response, distortion or maximum SPL exists, so the 20Hz extension and 40W/60W power ratings are unverified.
Buy the JBL Flip 6 at $79.95 for a medium speaker, or the Zealot S51 Pro at $39.97 for a speaker instead.
Want more options? Browse the full Portable Bluetooth rankings.
A very neutral speaker, very small, almost pocket size, a huge sound quality leap over the JBL Flip 5.
Amazon $89.97 Woot $79.95 Lowest eBay
The S51 Pro pairs a 40W amplifier (60W peak) with two 57mm drivers and two passive radiators in a 703g, 86 x 88 x 200mm cylinder, giving it more low-frequency hardware than most cheap portables.
Amazon $39.97 eBayPrices on this page were last checked October 19, 2026 at 10:32 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
| JBL Flip 6 | Zealot S51 Pro | |
|---|---|---|
| Price | $79.95 | $39.97 |
| Ranked | #13 of 173 in Medium Size Portable Bluetooth Speakers | - |
| App | Yes | - |
| Aux Input | No | Yes |
| Bass Extension (-10dB) | 56Hz | - |
| Battery Life | 12 hours (Manufacturer specified) | Up to 20 hours (at 50% volume) |
| Built-in Microphone | No | - |
| EQ | Yes (3 band) | 3 preset sound modes |
| IP Rating | IP67 | IPX6 |
| Bluetooth Latency | 116ms | - |
| Maximum SPL | 98dB (measured by Alan Ross Reviews) | - |
| Party Mode | Yes (PartyBoost up to 100 speakers) | - |
| Power Bank | No | - |
| Stereo | No | Yes |
| Omnidirectional | No | - |
| TWS | Yes | Yes (80W stereo pair) |
| Weight | 1.2 lbs (544 g) | 1.5 lbs (703g) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | AAC, SBC | - |
| Bluetooth Version | 5.1 | BT 5.2 |
| Dimensions | 6.9” x 2.7” x 2.8” (176 x 68 x 72 mm) | 3.4” x 3.5” x 7.9” (86 x 88 x 200 mm) |
| Drivers | 44mm x 80mm woofer, 16mm tweeter | 57mm x2 + 2 passive radiators |
| Power Input | USB-C | - |
| Amplifier Power | 30W | 40W (60W peak) |
| Digital Aux Input | No | - |
| Strap | Yes (built-in loop) | Yes (lanyard) |
| Battery Capacity | - | 6000mAh |
| Cabinet Color | - | Black |
| Cabinet Material | - | Nylon mesh grille |
| Frequency Response | - | 20Hz - 20kHz |
| Lights | - | RGB LED (beat-sync, multiple modes) |
| MicroSD Playback | - | Yes |
| USB Playback | - | Yes |