Short answer: the Harman Kardon Onyx Studio 9. It ranks #13 of 73 boombox speakers by sound quality at $186.99; the JBL Authentics 300 ranks #30 and costs $299.95, so there is not much of a tradeoff to weigh.
The case for the Harman Kardon Onyx Studio 9: Auracast multi-speaker connection alongside classic stereo pairing. Harman Kardon One app with EQ. Watch for: Slight recessed mids, boost in the upper mids, rolled off upper treble.
What the JBL Authentics 300 gets right: Integrates both Amazon Alexa and Google Assistant simultaneously (rare for smart speakers). Set against that: Narrow sounding, bass not as deep as others. Peaky upper mids. No TWS.
Buy the Harman Kardon Onyx Studio 9. It ranks higher for sound quality than the JBL Authentics 300 and costs less, so there is no real case for the other one.
Specifications Side By Side
| Harman Kardon Onyx Studio 9 | JBL Authentics 300 | |
|---|---|---|
| Price | $186.99 | $299.95 |
| Ranked | #13 of 73 in Boombox Size Portable Bluetooth Speakers | #30 of 73 in Boombox Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | 41Hz | 45Hz |
| Max Volume | 101dB | 100dB |
| IP Rating | None | None |
| Power Input | AC Power Cable (2-Prong) | AC Power cable |
| Stereo | Yes | Partially (1 woofer) |
| Omnidirectional | No | No |
| TWS | Yes | Yes |
| Weight | 9.3 lbs / 4.2 kg | 10.8 lbs / 4.9 kg |
| App | Yes (Harman Kardon One app) | Yes |
| Bluetooth Codecs | SBC | SBC |
| EQ | Yes (App EQ) | Yes (App EQ) |
| Party Mode | Yes (Auracast) | Yes (Wi-Fi Multi-Room) |
| USB Playback | No | Yes |
| Bluetooth Version | 5.3 | - |
| Battery Life | 8 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| Output Power | 50W RMS | 100W |
| Dimensions | 11.4" x 11.3" x 5.1" (289.2 x 287.5 x 130 mm) | 13.5" x 7.7" x 7.1" (342 x 195.6 x 180.3 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters | 1" tweeter + 4" woofer + passive radiators |
| Digital Aux Input | No | No |
| Wifi | - | Yes |
| Power Bank | - | No |
| Built in Microphone | - | Yes |
| MicroSD Playback | - | No |
| Aux Input | - | No |
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The Two Speakers In Full
Harman Kardon Onyx Studio 9: $186.99 Amazon
Pros: Auracast multi-speaker connection alongside classic stereo pairing. Harman Kardon One app with EQ. USB-C charging, up from the previous generation’s AC power brick.
Cons: Slight recessed mids, boost in the upper mids, rolled off upper treble. Not as deep bass as previous Onyx Studio speakers.
Full Harman Kardon Onyx Studio 9 review and specifications →
| App | Yes (Harman Kardon One app) |
|---|---|
| Bass Extension (-10dB) | 41Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Digital Aux Input | No |
| Dimensions | 11.4" x 11.3" x 5.1" (289.2 x 287.5 x 130 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters |
| EQ | Yes (App EQ) |
| IP Rating | None |
| Max Volume | 101dB |
| Omnidirectional | No |
| Output Power | 50W RMS |
| Party Mode | Yes (Auracast) |
| Power Input | AC Power Cable (2-Prong) |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | No |
| Weight | 9.3 lbs / 4.2 kg |
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JBL Authentics 300: $299.95 Amazon
Pros: Integrates both Amazon Alexa and Google Assistant simultaneously (rare for smart speakers). Retro seventies design with leather and Quadrex grille. 100-watt amp, carries well with leather-trimmed handle. Rechargeable battery rated ~8 hours.
Cons: Narrow sounding, bass not as deep as others. Peaky upper mids. No TWS. No IP rating. Not as loud as others. Not much battery life.
Full JBL Authentics 300 review and specifications →
| App | Yes |
|---|---|
| Aux Input | No |
| Bass Extension (-10dB) | 45Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Built in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 13.5" x 7.7" x 7.1" (342 x 195.6 x 180.3 mm) |
| Drivers | 1" tweeter + 4" woofer + passive radiators |
| EQ | Yes (App EQ) |
| IP Rating | None |
| Max Volume | 100dB |
| MicroSD Playback | No |
| Omnidirectional | No |
| Output Power | 100W |
| Party Mode | Yes (Wi-Fi Multi-Room) |
| Power Bank | No |
| Power Input | AC Power cable |
| Stereo | Partially (1 woofer) |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 10.8 lbs / 4.9 kg |
| Wifi | Yes |
As an eBay Partner, we may be compensated if you make a purchase.
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