Short answer: the Ultimate Ears Boom 4, though neither ranks well in its class. It ranks #113 of 175 medium speakers by sound quality (rated 2.9/5) at $129.99 and is still sold new; the Harman Kardon Esquire 2 ranks #155 (rated 2.3/5) and is discontinued, so it is only an option used. Both are rated below 3.0/5 among the 175 medium speakers; for better sound, the EarFun Uboom L ranks #2 at $49.79.
The Ultimate Ears Boom 4 is the better-sounding, longer-running option. IP67 rated, floats, and finally charges via USB-C instead of the older Booms’ Micro-USB. It is rated for 15 hours of battery against 8 for the Harman Kardon Esquire 2. It is rated IP67 against IPX4 for the Harman Kardon Esquire 2. It has an adjustable EQ, which the Harman Kardon Esquire 2 lacks. The tradeoff: Not much improvement over the old ones.
The Harman Kardon Esquire 2 is the lighter option. Doubles as a conferencing speakerphone with a 4-mic array and noise/echo cancellation. At 0.8 lbs (350 g) it weighs much less than the Ultimate Ears Boom 4 at 1.4 lbs (620 g). It keeps a wired aux input, which the Ultimate Ears Boom 4 lacks. The catch: Bass is weak, vocal and instrument separation is underwhelming and sounds tinny at high volume.
Buy the Ultimate Ears Boom 4. It is rated higher for sound quality; the Harman Kardon Esquire 2 is no longer sold new.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Specifications Side By Side
| Ultimate Ears Boom 4 | Harman Kardon Esquire 2 | |
|---|---|---|
| Price | $129.99 | $200 Discontinued |
| Ranked | #113 of 175 in Medium Size Portable Bluetooth Speakers | #155 of 175 in Medium Size Portable Bluetooth Speakers |
| App | Yes | No |
| Battery Life | 15 hours (Manufacturer specified) | 8 hours (Manufacturer specified) |
| IP Rating | IP67 | IPX4 |
| Power Input | USB-C | Micro USB |
| Stereo | Yes | No |
| Omnidirectional | No | No |
| Weight | 1.4 lbs (620 g) | 0.8 lbs (0.35 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 5.1 | 4.1 |
| Dimensions | 7.2” x 2.9” x 2.9” (184 x 73 x 73 mm) | 7.5” x 5.1” x 1.3” (190 x 130 x 34 mm) |
| Drivers | 2x 1.57” (40mm) active drivers + 2x 1.81” x 2.57” (46.1 x 65.2mm) passive radiators | 4x 1.25” (32mm) full-range drivers |
| TWS | Yes | No |
| EQ | Yes (via app) | No |
| Built-in Microphone | No | Yes |
| Power Bank | No | Yes (USB-A) |
| Aux Input | No | Yes |
| Maximum SPL | 85dBC (Manufacturer specified) | - |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC | SBC |
| Strap | Yes (built-in loop) | - |
| Amplifier Power | - | 16W |
Related Speaker Comparisons
How Ultimate Ears Boom 4 compares with other leading options:
- Ultimate Ears Boom 4 vs EarFun Uboom L
- Soundcore Motion 300 vs Ultimate Ears Boom 4
- Soundcore Motion+ vs Ultimate Ears Boom 4
- Soundcore Boost “upgraded” 2021 vs Ultimate Ears Boom 4
- Ultimate Ears Boom 4 vs Minirig 4
Prices on this page were last checked October 12, 2026 at 4:13 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
Ultimate Ears Boom 4: $129.99 Amazon $129.99 eBay
Older model: the Ultimate Ears Boom 3 (ranked lower, rated 2.9/5). See every Ultimate Ears Wonderboom, Boom and Megaboom generation.
Same family: the Ultimate Ears Wonderboom 4 (smaller model, ranked higher, rated 2.9/5) and the Ultimate Ears Megaboom 4 (larger model, ranked lower, rated 2.1/5).
Pros: IP67 rated, floats, and finally charges via USB-C instead of the older Booms’ Micro-USB. 15 hour battery. Customizable EQ and speaker-pairing via the UE app.
Cons: Not much improvement over the old ones. Weak bass extension and thuddy bass. Gets distorted above 90%
Full Ultimate Ears Boom 4 review and specifications →
| Released | Jun 2024 (2 years ago) |
|---|---|
| App | Yes |
| Aux Input | No |
| Battery Life | 15 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.1 |
| Built-in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 7.2” x 2.9” x 2.9” (184 x 73 x 73 mm) |
| Drivers | 2x 1.57” (40mm) active drivers + 2x 1.81” x 2.57” (46.1 x 65.2mm) passive radiators |
| EQ | Yes (via app) |
| IP Rating | IP67 |
| Maximum SPL | 85dBC (Manufacturer specified) |
| Omnidirectional | No |
| Power Bank | No |
| Power Input | USB-C |
| Stereo | Yes |
| Strap | Yes (built-in loop) |
| TWS | Yes |
| Weight | 1.4 lbs (620 g) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Ultimate Ears Boom 4 vs Ultimate Ears Boom 3
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom
- Ultimate Ears Boom 4 vs Klipsch Groove
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom 2
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom 3
- Ultimate Ears Boom 4 vs Ultimate Ears Wonderboom 4
- Ultimate Ears Boom 4 vs DBSONO X-Blast F37
- Ultimate Ears Boom 4 vs Sony SRS-XE300
- See all 139 comparisons
Harman Kardon Esquire 2: $200 Discontinued eBay
Pros: Doubles as a conferencing speakerphone with a 4-mic array and noise/echo cancellation. Flat, compact design packs easily. USB charge-out for topping off a phone.
Cons: Bass is weak, vocal and instrument separation is underwhelming and sounds tinny at high volume. Discontinued.
Full Harman Kardon Esquire 2 review and specifications →
| Released | 2015 (11 years ago) |
|---|---|
| Amplifier Power | 16W |
| App | No |
| Aux Input | Yes |
| Battery Life | 8 hours (Manufacturer specified) |
| Bluetooth | Yes |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 4.1 |
| Built-in Microphone | Yes |
| Digital Aux Input | No |
| Dimensions | 7.5” x 5.1” x 1.3” (190 x 130 x 34 mm) |
| Drivers | 4x 1.25” (32mm) full-range drivers |
| EQ | No |
| IP Rating | IPX4 |
| Omnidirectional | No |
| Power Bank | Yes (USB-A) |
| Power Input | Micro USB |
| Stereo | No |
| TWS | No |
| Weight | 0.8 lbs (0.35 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Harman Kardon Esquire 2 vs Ultimate Ears Roll 2
- Harman Kardon Esquire 2 vs Tribit Stormbox Mini
- Harman Kardon Esquire 2 vs LG Xboom XG5
- Harman Kardon Esquire 2 vs LG Xboom Go PL5
- Harman Kardon Esquire 2 vs Sony SRS-XE200
- Harman Kardon Esquire 2 vs Tribit Stormbox Mini+
- Harman Kardon Esquire 2 vs Ultimate Ears Megaboom 4
- Harman Kardon Esquire 2 vs Zealot S61
- See all 72 comparisons