Short answer: the Ultimate Ears Epicboom for battery life, the Harman Kardon Onyx Studio 4 for bass. The Epicboom runs 17 hours and is the first UE portable with USB-C charging, but its bass is not very deep for the size. The Onyx Studio 4 offers deep resonant bass, crisp treble and a large dynamic range, though its battery manages 8 hours at medium volume, at $100 against $213.41.
Buy the Ultimate Ears Epicboom if you want one new; the Harman Kardon Onyx Studio 4 is discontinued, so only look for it used.
If water resistance matters to you, the Ultimate Ears Epicboom at IPX7 (brief submersion) holds up far better than the Harman Kardon Onyx Studio 4 at no water resistance.
Still deciding? The full Portable Bluetooth rankings cover every ranked option.
Specifications Side By Side
| Harman Kardon Onyx Studio 4 | Ultimate Ears Epicboom | |
|---|---|---|
| Price | $100 Discontinued | $213.41 |
| Ranked | #58 of 93 in Large Size Portable Bluetooth Speakers | #73 of 93 in Large Size Portable Bluetooth Speakers |
| App | Yes (HK Connect) | No |
| Aux Input | Yes | Yes |
| Battery Life | 8 hours (Manufacturer specified) | 17 hours (Manufacturer specified) |
| EQ | No | No |
| IP Rating | None | IPX7 |
| Party Mode | Yes (Connect+ up to 100 speakers) | No |
| Power Bank | No | No |
| TWS | Yes | Yes |
| Weight | 4.5 lbs (2.06 kg) | 4.3 lbs (1.97 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC | SBC |
| Built-in Microphone | Yes | Yes |
| Power Input | DC Barrel Connector (19V/2.1A) | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| Bluetooth Version | 4.2 | 5.2 |
| Drivers | 2x 75mm woofers + 2x 20mm tweeters + 1x passive radiator | 1x 120mm woofer, 2x 45mm tweeters |
| Dimensions | 11.4” x 11.4” x 5.1” (290 x 290 x 130 mm) | 4.7” x 9.5” x 6.4” (119 x 241 x 162 mm) |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) | 50Hz - 20kHz (Manufacturer specified) |
| Amplifier Power | 60W | 10W RMS |
| Digital Aux Input | No | No |
| Strap | No | Yes (built-in loop) |
| Bass Extension (-10dB) | - | ~55Hz |
| Maximum SPL | - | 94dB (Manufacturer specified) |
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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
Harman Kardon Onyx Studio 4: $100 Discontinued eBay
Newer model: the Harman Kardon Onyx Studio 9, rated 4.1/5.
Pros: Balanced sound quality with deep resonant bass and crisp treble, large dynamic range. Multi-host Bluetooth connectivity for 2 phones, daisy chaining up to 100 speakers. Elegant modern design with smooth curves and premium materials.
Cons: 8 hour battery at medium volume. Not at loud as others. Not as deep of bass as the newer Onyx. External AC power brick for charging. Discontinued.
Full Harman Kardon Onyx Studio 4 review and specifications →
| Amplifier Power | 60W |
|---|---|
| App | Yes (HK Connect) |
| Aux Input | Yes |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 4.2 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 11.4” x 11.4” x 5.1” (290 x 290 x 130 mm) |
| Drivers | 2x 75mm woofers + 2x 20mm tweeters + 1x passive radiator |
| EQ | No |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) |
| IP Rating | None |
| Omnidirectional | No |
| Party Mode | Yes (Connect+ up to 100 speakers) |
| Power Bank | No |
| Power Input | DC Barrel Connector (19V/2.1A) |
| Stereo | Yes |
| Strap | No |
| TWS | Yes |
| Weight | 4.5 lbs (2.06 kg) |
- Links
- Reviews, Comparisons and Sound Samples
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Ultimate Ears Epicboom: $213.41 Amazon eBay
Pros: 17 hour battery with USB-C charging (first UE portable with USB-C). IP67 rating, floats in water. Made mostly from recycled fabric and plastic. Large best-sounding UE portable that still feels portable. 180ft Bluetooth range. Measured bass extension of ~55Hz (-10dB).
Cons: Not very deep bass for the size. Gets distorted at around 70-80% with bass thuds.
Full Ultimate Ears Epicboom review and specifications →
| Amplifier Power | 10W RMS |
|---|---|
| App | No |
| Aux Input | Yes |
| Bass Extension (-10dB) | ~55Hz |
| Battery Life | 17 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.2 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 4.7” x 9.5” x 6.4” (119 x 241 x 162 mm) |
| Drivers | 1x 120mm woofer, 2x 45mm tweeters |
| EQ | No |
| Frequency Response | 50Hz - 20kHz (Manufacturer specified) |
| IP Rating | IPX7 |
| Maximum SPL | 94dB (Manufacturer specified) |
| Omnidirectional | No |
| Party Mode | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | Yes (built-in loop) |
| TWS | Yes |
| Weight | 4.3 lbs (1.97 kg) |
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