Short answer: the Harman Kardon Onyx Studio 9. It ranks #13 of 70 boombox speakers by sound quality at $186.99; the JBL Boombox 4 ranks #17 and costs $549.95, so there is not much of a tradeoff to weigh.
What the Onyx Studio 9 gets right: Auracast multi-speaker connection, USB-C charging, and an EQ-capable app, for a third of the price. The catch: slightly recessed mids and rolled-off upper treble.
On the JBL Boombox 4 side: Pretty insane output capability for its size. The tradeoff: pretty overpriced for the category, and out of the box it sounds worse than the older Boombox 3.
Buy the Harman Kardon Onyx Studio 9. It ranks higher for sound quality than the JBL Boombox 4 and costs less, so there is no real case for the other one.
Specifications Side By Side
| Harman Kardon Onyx Studio 9 | JBL Boombox 4 | |
|---|---|---|
| Price | $186.99 | $549.95 |
| Ranked | #13 of 70 in Boombox Size Portable Bluetooth Speakers | #17 of 70 in Boombox Size Portable Bluetooth Speakers |
| Bass Extension (-10dB) | 41Hz | 41Hz |
| Max Volume | 101dB | 115dB |
| IP Rating | None | IP68 |
| Power Input | USB-C | AC Power cord |
| Stereo | Yes | Yes |
| TWS | Yes | Yes |
| Weight | 9.3 lbs / 4.2 kg | 13.2 lbs / 5.98 kg |
| App | Yes (Harman Kardon One app) | Yes |
| Bluetooth Codecs | SBC | SBC, LC3, AAC |
| EQ | Yes (App EQ) | No |
| Party Mode | Yes (Auracast) | Yes (Auracast) |
| USB Playback | No | No |
| Bluetooth Version | 5.3 | - |
| Battery Life | 8 hours (Manufacturer specified) | 28 hours (Manufacturer specified) |
| Output Power | 50W RMS | 210W AC / 200W battery |
| Dimensions | 11.4" x 11.3" x 5.1" (289.2 x 287.5 x 130 mm) | 20.1" x 10.2" x 8.3" (510 x 260 x 210 mm) |
| Drivers | 120mm woofer + 3x 20mm tweeters | 2x 123mm woofers + 2x 20mm tweeters with passive radiators |
| Aux Input | - | No |
| Bluetooth Latency | - | AAC 144ms, SBC 48ms |
| Removable Battery | - | Yes |
| Built in Microphone | - | No |
| Power Bank | - | Yes |
| Digital Aux Input | - | Yes (USB-C) |
| FM Tuner | - | No |
| Microphone Input | - | No |
| MicroSD Playback | - | No |
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.
| App | Yes (Harman Kardon One app) |
|---|---|
| Bass Extension (-10dB) | 41Hz |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| 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 |
| Output Power | 50W RMS |
| Party Mode | Yes (Auracast) |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | No |
| Weight | 9.3 lbs / 4.2 kg |
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- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Harman Kardon Onyx Studio 9 vs Zealot ZE41
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JBL Boombox 4: $549.95 Amazon Bhphotovideo
Pros: Pretty insane output capability for the size.
Cons: Pretty overpriced for the category. Better than the Boombox 3 mostly because there are more 7 EQ bands instead of just 3 and it can be better tuned. Try Oluv’s EQ for it. Out of the box sounds worse than the Boombox 3. No Aux input.
| App | Yes |
|---|---|
| Aux Input | No |
| Bass Extension (-10dB) | 41Hz |
| Battery Life | 28 hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, LC3, AAC |
| Bluetooth Latency | AAC 144ms, SBC 48ms |
| Built in Microphone | No |
| Digital Aux Input | Yes (USB-C) |
| Dimensions | 20.1" x 10.2" x 8.3" (510 x 260 x 210 mm) |
| Drivers | 2x 123mm woofers + 2x 20mm tweeters with passive radiators |
| EQ | No |
| FM Tuner | No |
| IP Rating | IP68 |
| Max Volume | 115dB |
| MicroSD Playback | No |
| Microphone Input | No |
| Output Power | 210W AC / 200W battery |
| Party Mode | Yes (Auracast) |
| Power Bank | Yes |
| Power Input | AC Power cord |
| Removable Battery | Yes |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | No |
| Weight | 13.2 lbs / 5.98 kg |
As an eBay Partner, I may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- JOY‘s 🎧3D🔈Audio-Show: JBL Boombox 4 vs Boombox 3 - old one sounding better? 🤔
- JOY‘s 🎧3D🔈Audio-Show: JBL Boombox 4 vs Earfun UBoom X - sound test
- JOY‘s 🎧3D🔈Audio-Show: JBL Boombox 4 vs Boombox 3 - any improvement?
- JOY‘s 🎧3D🔈Audio-Show: JBL Boombox 4 vs Partybox Encore 2 - outdoor loudness & basstest
- JOY‘s 🎧3D🔈Audio-Show: JBL Boombox 4 - finally a real BOOMbox from JBL 👏
- Alan Ross Reviews: JBL Boombox 4 HUMILIATES Brane X?! Ultimate Bass Battle!
- Alan Ross Reviews: JBL Boombox 4 Compared to Boombox 3 & 3 WiFi – Worth the Upgrade?
- Alan Ross Reviews: JBL Boombox 4 distortion fest bonanza! how bad can it be lol 🤣
- Jagist reviews: Jbl Boombox 4 Vs Zealot Ze21!!!
- Techder Audios: JBL Boombox 4 VS Zealot ZE21 BATTLE OF THE BOOMBOXES!
- Dominik Reviews: Zealot S89 vs JBL Boombox 4 - JBL Alternative? Sound Test
- Jagist reviews: Jbl Boombox 4 Vs Zealot S89!!!
- Jagist reviews: Jbl Boombox 4 Vs Zealot S95!!!
- Reddit Search for JBL Boombox 4 Review
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Product prices and availability were last checked August 10, 2026 at 7:14 AM UTC 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.