Different classes, so treat this as a step-up-or-not question rather than a head-to-head. The Brane X ranks #4 of 117 large speakers by sound quality at $549; the JBL Authentics 300 ranks #46 of 112 boombox speakers by sound quality at $299.95.
The Brane X is the louder, deeper-bass pick. A portable speaker with extraordinarily deep bass for its size, plus Wi-Fi, AirPlay, Alexa and a low latency aux input. Its bass reaches about 31Hz before falling 10dB, against 45Hz for the JBL Authentics 300. Alan Ross Reviews measured it at 106dB at full volume, against 100dB for the JBL Authentics 300. It is rated for 12 hours of battery against 8 for the JBL Authentics 300. The tradeoff: The front-facing design has only moderate dispersion, so sound changes noticeably off to the sides or behind it.
Why pick the JBL Authentics 300: A retro styled smart speaker with both Alexa and Google Assistant, a leather handle and battery power. The catch: Narrow sounding, bass not as deep as others.
Buy the Brane X at $549 for a large speaker, or the JBL Authentics 300 at $299.95 for a boombox speaker instead.
There is a real gap in water resistance: the Brane X at IP57 (brief submersion) against the JBL Authentics 300, which has no water resistance.
Looking for alternatives? See the complete Portable Bluetooth rankings.
A portable speaker with extraordinarily deep bass for its size, plus Wi-Fi, AirPlay, Alexa and a low latency aux input.
A retro styled smart speaker with both Alexa and Google Assistant, a leather handle and battery power.
Prices on this page were last checked November 5, 2026 at 10:30 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
| Brane X | JBL Authentics 300 | |
|---|---|---|
| Price | $549.00 | $299.95 |
| Ranked | #4 of 117 in Large Size Portable Bluetooth Speakers | #46 of 112 in Boombox Size Portable Bluetooth Speakers |
| Aux Input | Yes | No |
| Aux Latency | 295ms default, 33ms with aux pass-through | - |
| Bass Extension (-10dB) | 31Hz | 45Hz |
| Battery Life | 12 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | aptX HD, aptX, AAC, SBC | SBC |
| IP Rating | IP57 | None |
| Bluetooth Latency | 100ms | - |
| Maximum SPL | 106dB (measured by Alan Ross Reviews) | 100dB (measured by Alan Ross Reviews) |
| Party Mode | Yes (Brane app, up to 8 speakers) | Yes (Wi-Fi Multi-Room) |
| Power Input | AC Power brick | AC Power cable |
| Stereo | Yes | Partially (1 woofer) |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 7.7 lbs (3.5 kg) | 10.8 lbs (4.9 kg) |
| Wi-Fi | Yes | Yes |
| App | Yes (Brane app) | Yes |
| Built-in Microphone | Yes | Yes |
| Voice Assistants | Amazon Alexa | Amazon Alexa & Google Assistant (simultaneous) |
| EQ | Yes (5 band) | Yes (App EQ) |
| Power Bank | No | No |
| Dimensions | 9.3” x 7” x 6.1” (236 x 178 x 155 mm) | 13.5” x 7.7” x 7.1” (342 x 195.6 x 180.3 mm) |
| Drivers | 2x 2.5” midrange, 2x 0.75” tweeters + 6.5”x9” subwoofer | 1” tweeter + 4” woofer + passive radiators |
| Frequency Response | 30Hz - 20kHz (Manufacturer specified) | - |
| Amplifier Power | 200W | 100W |
| Digital Aux Input | No | No |
| Bluetooth Version | 5.1 | 5.3 |
| Strap | No | No |
| USB Playback | - | Yes |
| MicroSD Playback | - | No |
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