Audio review
Ultimate Ears Boom 4 Review: Twenty Hours, Not Fifteen
The battery claim is one of the few in this catalogue that a tester beat rather than missed, by more than five hours. The charging port sits above the waterline when it floats.
By Paulo GerchonPublished 2 min read
Illustration, not a photo — we don’t have a licensed image of this product yet.
Ultimate Ears
Ultimate Ears Boom 4
Excellent · researched from 3 sources
The battery is the standout and the ruggedness is genuine down to where they put the charging port. Keep it for a pool, a picnic or a bathroom rather than a party, because 85 decibels is where it stops.
- Buy if
- Pools, beaches and bathrooms, on IP67 and the fact it floats · Long days outdoors, on a measured twenty hours · Listening from any direction, which the 360 degree design handles
- Skip if
- Large gatherings, given the 85 dBC ceiling · Calls, since there is no microphone · Switching between a phone and a laptop, with no multipoint
We don’t list prices, because Amazon’s change hourly.
A battery claim that survives testing
Ultimate Ears says 15 hours at 30 percent volume.
What's The Best played it for over 20 hours and still had 40 percent of the battery showing.
That is worth dwelling on, because almost every portable speaker reviewed in this catalogue falls short of its stated figure under test. The Marshall Emberton II managed a third of its claim on SoundGuys' rig. The JBL Flip 6 and the Bose SoundLink Flex both came in well under.
Gear Brain's version is less precise and points the same way: an entire day outdoors at moderate volume.
Where the ruggedness was thought through
IP67, submersible to a metre for half an hour, and it floats. What's The Best confirmed it working after submersion.
The detail that makes the difference is theirs: the charging port sits above the waterline when the speaker is floating. That is a design decision rather than a rating, and it is the kind of thing that separates a speaker built for water from one merely sealed against it.
Gear Brain adds drop resistance to the list.
Eighty-five decibels
Gear Brain measured the maximum at 85 dBC and says plainly it will not replace a larger party speaker.
HiFi Picks credits it with staying crisp and clean up there without the distortion most portables develop, and Gear Brain found very little distortion at volume. What's The Best is the dissent, hearing some at maximum.
Practically, that ceiling covers a bathroom, a kitchen, a picnic table or a poolside. It does not cover a garden with a dozen people talking.
The bass argument
Gear Brain: deep, controlled and punchy, holding clarity as it gets louder.
HiFi Picks: balanced 360 degree sound with deep bass, and mids that can be overshadowed by it.
What's The Best: thin at low volume, better as you turn it up, and some familiar tracks sounding thinner than they do elsewhere. They also found the bass-heavy presets coming out muffled.
Three listeners, three readings, one clear implication: this ships tuned toward the low end, and the app contains a full graphic equaliser rather than only presets. Use it.
The omissions
No microphone. No calls, no voice assistant.
No multipoint, per HiFi Picks, so it holds a single device and switching means re-pairing.
And Gear Brain points out there is no USB-C cable in the box, on a speaker that charges over USB-C.
What you do get is PartyUp, which links more than 150 compatible Ultimate Ears speakers, and five EQ presets alongside the graphic equaliser.
How it scored
The overall 8.5 is the weighted average of these five criteria — we never adjust it by hand.
Sound quality
Gear Brain praises deep controlled bass with very little distortion at volume. What's The Best finds the bass thin at low levels, and HiFi Picks says the mids can be overshadowed.
Value
Gear Brain calls it one of the best Bluetooth speakers in its class. What's The Best scored it 4 out of 5.
Build quality
IP67 and it floats, with What's The Best noting the charging port is positioned above the waterline when it does. Drop-resistant as well as waterproof.
Ease of use
A full graphic equaliser and five presets in the app, though HiFi Picks finds initial pairing sluggish and notes there is no multipoint.
Battery
Rated 15 hours at 30 percent volume. What's The Best got past 20 hours with 40 percent still showing, and Gear Brain says it lasts a full day outdoors.
Pros and cons
What we liked
- What's The Best exceeded 20 hours of playback against a 15 hour claim
- IP67, floats, and the charging port sits above the waterline
- Two 40 mm drivers and two passive radiators in a 360 degree cylinder
- Gear Brain found very little distortion even at higher volumes
- A full graphic equaliser plus five presets in the app
- PartyUp links more than 150 compatible Ultimate Ears speakers
What we didn’t
- Gear Brain measured maximum output at 85 dBC, which will not fill a garden
- HiFi Picks says the midrange can be overshadowed by the bass
- What's The Best found the bass thin at low volume and detected distortion at maximum
- There is no microphone, so calls and voice assistants are out
- No multipoint, per HiFi Picks, so it holds one device at a time
- Gear Brain notes no USB-C cable is supplied
Specifications
| Drivers | Two 40 mm active drivers and two passive radiators |
|---|---|
| Battery | 15 hours claimed at 30 percent volume; over 20 hours measured by What's The Best |
| Recharge | About three hours over USB-C |
| Maximum volume | 85 dBC per Gear Brain |
| Water resistance | IP67, submersible to a metre for 30 minutes, and it floats |
| Weight | 620 g |
| Dimensions | 184 x 73 x 73 mm per What's The Best |
| Range | About 45 metres per What's The Best |
| App | Graphic equaliser plus Signature, Bass Boost, Cramped Spaces, Deep Relaxation and Podcast presets |
| Multi-speaker | PartyUp, over 150 speakers |
How we researched this
We have not had this unit on the bench. This review synthesises the manufacturer’s published specifications, independent measurements and owner reports listed below. Every figure on this page comes from one of those sources rather than our own measurement.
3
sources reviewed
Gear Brain supplies the measured maximum output in decibels, the driver configuration, the weight and dimensions and the criticism about the missing cable. What's The Best supplies the battery result that beats the claim, the observation about the charging port position when floating, the wireless range and the criticisms of the bass at low volume. HiFi Picks supplies the midrange assessment, the recharge time, the app behaviour and the multipoint limitation. The three disagree about distortion at maximum volume, and both positions are reported.
What we read
Common questions
How long does the Ultimate Ears Boom 4 battery really last?
Does it actually float?
How loud does it go?
What does it sound like?
What is it missing?
The bottom line on the Ultimate Ears Boom 4
The battery is the standout and the ruggedness is genuine down to where they put the charging port. Keep it for a pool, a picnic or a bathroom rather than a party, because 85 decibels is where it stops.
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