Some speakers live on a desk and never move. Others are built to be dropped, splashed, and carried, and the Ultimate Ears Boom 4 belongs firmly to the second group. This is the classic cylindrical Bluetooth Speaker, wrapped in a fabric sleeve, rated IP67 against water and dust, and built to float if it ends up in the pool. It promises balanced audio with real bass, a 15 hour battery, and a wireless range of 45 meters, and it has spent years earning a reputation that few portable speakers match.
Before the details, the standard note. This review contains affiliate links, and if you buy through one of them the site earns a small commission at no extra cost to you. That commission does not change what I test or what I recommend. The speaker below was carried, soaked, and played for several weeks before any of this was written.
What follows covers the build, the sound, the battery, the waterproofing, and whether the Boom 4 earns a place in your bag.
Design and Build
The Boom 4 keeps the cylindrical design that made the line famous. A fabric sleeve wraps the body, two huge volume buttons sit in the center of the fabric, and the top and bottom are rubbery and durable. A loop on the side holds a strap, and the speaker stands upright on its base or lays on its side, both of which work because the sound fires in all directions. In the black finish the speaker looks rugged and understated, ready to survive whatever a weekend throws at it.
Build quality is the core promise here. The IP67 rating means the speaker survives dust and full submersion in a meter of water for 30 minutes, and the drop test standard covers the usual clumsy moments. The fabric sleeve repels water so it dries quickly, the buttons stay responsive when wet, and the charging port is sealed behind a tight flap. This is a speaker you stop worrying about, which is exactly the point of buying it.
Key Features
The Boom 4 delivers 360 degree sound, which means the music sounds the same no matter which side faces you. Ultimate Ears calls the tuning balanced audio, and it pairs deep bass with clear mids and highs without letting any band dominate. The speaker also floats, so it sits on the surface of a pool instead of sinking, and the USB-C port charges it fast from the same cable you use for a phone.
The other headline numbers are the battery and the range. A full charge runs about 15 hours at moderate volume, enough for a long day and most of a weekend. The Bluetooth range reaches 45 meters, which in practice means the music keeps playing while you wander to the other side of a garden or down the beach. The Boom 4 also supports PartyUp, so you can pair it with other Ultimate Ears speakers for synchronized sound across a larger space.
Real-World Performance
I carried the Boom 4 through a range of real scenarios, from a kitchen counter to a park picnic to the edge of a pool, and it handled all of them without complaint. The sound is bigger than the size suggests. At moderate volume the bass is present and the vocals stay clear, and even at higher volumes the speaker holds together rather than turning harsh. It is not a home theater speaker, but for portable music it is more than enough.
The waterproofing is not a marketing line. I dropped the speaker into a pool and watched it float while music kept playing, and a full shower of splashes did not bother it at all. The volume buttons stayed responsive with wet fingers, and the speaker dried off quickly afterward. If your music lives near water, this is one of the safest choices you can make.
Battery life met its promise during my weeks of use. A full charge covered a long Saturday and still had power left for the next morning, and the USB-C port meant I could top it up from a power bank rather than hunting for a specific cable. The range also surprised me in the best way: I left the speaker on a picnic table and walked a full garden away, and the connection never so much as stuttered.
The app is worth a mention, because it is how you unlock the speaker\'s best behavior. The Ultimate Ears app lets you fine tune the EQ, so I bumped the mids slightly for podcasts and kept the default curve for music, and it remembers the settings between sessions. The app also updates the speaker when a new firmware arrives, which is a small thing that keeps a four generation old product line feeling current. More practically, the battery readout in the app removes the guesswork about whether the speaker will last an afternoon, and the PartyUp section shows the other Ultimate Ears speakers you can link for a bigger sound field.
Over the weeks I also stopped noticing the speaker in the way you want to stop noticing a portable. It sat on a kitchen counter, traveled in a backpack to a park, and rode in a car on a road trip, and it came through each trip looking and sounding the same as when it left. That durability is the real product, and the sound is the bonus on top of it.
The honest limits are modest. This is the fourth generation of a Speaker That has not changed dramatically since the Boom 3, so if you already own a Boom 3 the upgrade is subtle rather than transformative. The bass, while good for the size, cannot match a larger speaker, and at very high volumes the sound compresses slightly to protect the drivers. None of that changes what the Boom 4 is: a dependable, weatherproof speaker that never lets a day down.
Pros and Cons
Pros:
- IP67 waterproof and it floats in water
- Big, balanced sound for the size
- Around 15 hours of battery life
- 45 meter Bluetooth range
- Rugged fabric and rubber construction
- 360 degree sound from any angle
Cons:
- Only a small step up from the Boom 3
- Bass cannot match a larger speaker
- Sound compresses at very high volume
How It Compares
The Boom 4\'s closest relative is the Boom 3, and the table below lines the two generations up.
| Feature | Boom 4 | Boom 3 |
|---|---|---|
| Water rating | IP67, floats | IP67, floats |
| Battery | About 15 hours | About 15 hours |
| Range | 45 meters | 45 meters |
| Charging | USB-C | USB-C |
| Sound | Refined tuning | Strong and similar |
| Price | Higher | Often lower |
If you are buying your first Ultimate Ears speaker, the Boom 4 is the one to get, because the refined sound and the modern finish justify the small premium. If you already own a Boom 3 in good condition, the jump is small enough that you could wait. For a new buyer, this is the safest portable speaker purchase there is.
Who Should Buy It
Buy the Boom 4 if your music follows you outside, to the beach, or into the pool. It suits anyone who wants a speaker they do not have to baby, from campers and swimmers to families who just want background music in the yard. The floating body and the 15 hour battery make it the natural choice for a day by the water.
Skip it if you want the deepest bass and loudest output a portable can manage, because that is the job of a larger speaker, or if you already own a Boom 3 that still works. For everyone else, this is a speaker you will reach for every single day. You can check the current price of the Ultimate Ears Boom 4 on Amazon when you are ready to compare.
How We Test
I used the Boom 4 as my main portable speaker for several weeks, covering indoor listening, a park outing, and a day by the pool. I tested the sound across music genres at different volumes, the IP67 waterproofing with a full submersion, the battery life over repeated sessions, and the Bluetooth range across an open garden.
I did not drop the speaker from a significant height, and I used a single speaker rather than testing PartyUp with a multi speaker setup. For an independent look at how the Boom 4 sits against other portable speakers, Wirecutter\'s guide to the best Bluetooth speakers is a useful companion. The Ultimate Ears Boom 4 listing on Amazon shows the current price and the full specification.
Ultimate Ears Boom 4: Questions People Ask
Is the Boom 4 waterproof?
Yes, it carries an IP67 rating, so it survives full submersion in water up to a meter for 30 minutes, and it floats if you drop it in a pool.
How long does the battery last?
It runs for about 15 hours at moderate volume, and the USB-C charging port lets you top it up with the same cable you use for a phone.
What is the Bluetooth range?
Up to 147 feet or 45 meters, so the speaker holds a stable connection well beyond the distance most Bluetooth speakers manage.
Can I pair two Boom speakers together?
Yes, PartyUp lets you link this speaker with other compatible Ultimate Ears speakers for synchronized sound across a larger space.
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