Ultimate Ears BOOM 4 Speaker Review

The Ultimate Ears BOOM 4 is very similar in appearance to its predecessor, the Ultimate Ears BOOM 3. It's small and cylindrical in shape, designed to sit vertically on any surface. It features the brand's signature oversized volume +/- buttons, with additional controls found on the top of the speaker. There's also a discreet built-in hook on the top that you can use to fasten it to a bag or strap. There's no built-in hand strap, like with the Ultimate Ears WONDERBOOM PLAY, though. You charge it via a covered USB-C port on the bottom. It comes in a few different finish options, including 'Active Black,' 'Raspberry Red,' 'Cobalt Blue,' and 'Enchanting Lilac.'

This speaker is extremely portable and easy to bring around with you on your day-to-day. It's roughly the size of a small bottle or large can (to the point where it fits in cupholders), so it can be easily carried in one hand and slipped into a tote bag. It's light, too, and could even be stowed away in a large jacket pocket in a pinch without weighing you down too much.

As with the previous generation, this speaker has an outstanding build quality. It's rated IP67 for dust and water resistance, making it suitable for submersion in water for up to 30 minutes. The manufacturer also claims it can float in water and that it's impact resistant, though they don't specify to what extent. The fabric covering the driver grille is taut and grippy, so it stays in your hand while you hold it. There are rubber end caps at the top and bottom of the speaker, as well as a rubber flap that covers the USB-C charging port.

This speaker comes with a basic set of controls that allow you to adjust functions like volume, pairing, and audio playback, with dedicated buttons for each. The buttons themselves are tactile and nicely texturized. You can press both volume buttons simultaneously to voice feedback on the battery level. There are also chimes that sound when entering Bluetooth pairing mode and when turning the speaker on/off. The buttons themselves aren't labelled in the most intuitive way, though, so it's not obvious at first glance which functions each button corresponds to.

• Ultimate Ears BOOM 4 speaker
• USB-C charging cable
• Quick start guide and warranty information

The Ultimate Ears BOOM 4 has a sub-par frequency response accuracy. While there's slightly more bass than the previous generation, this speaker is by no means bass-heavy. The thumpy four-on-the-floor kicks of house and techno tracks lack some oomph, though their punchy attack can still be heard. There's some roll-off in the treble range, too, that can cause sibilants, like cymbals, to sound a little dull. That said, the mid-range is well-balanced, so vocals and speech are reproduced with plenty of detail. You can also use the graphic EQ and presets in the companion app to alter the sound somewhat, although this won't help you overcome the lack of bass that's inherent to its design. Check out the otherwise similarly capable Ultimate Ears MEGABOOM 4 for a greater bass extension.

As with other Ultimate Ears speakers, this speaker's soundstage performance is incredible. It can playback stereo content without downmixing to mono. The speaker's directivity is the standout feature here, as it can deliver audio consistently across almost every listening angle, thanks to its 360-degree design.

The dynamics performance is decent; while it can't get particularly loud, it's enough to fill a small room with sound. There's also not much compression present as you turn the volume up, save for some pumping artifacts in the bass range.

The Ultimate Ears BOOM 4 has an excellent battery life performance. The manufacturer advertises up to 15 hours of playtime, and we were able to achieve close to this, with 12.1 hours in testing. Of course, battery life varies according to numerous factors, so your experience will vary. There's a handy auto-off timer that helps you conserve battery life by shutting the speaker off automatically after 15 minutes of inactivity. Many users will also be happy to see the inclusion of USB-C charging with this generation, too, marking a switch from the micro-USB ports used in previous BOOM speakers.

This speaker doesn't have a built-in microphone. If you're looking for a portable home speaker to use with your phone's voice assistant, consider the Sony LinkBuds Speaker.

This Ultimate Ears BOOM 4 is compatible with the Ultimate Ears app, which lets you adjust a range of parameters and use unique features, like the Megaphone function (which lets you speak into your phone's mic and play it back on the speaker). You can also use the PartyUp feature to pair with other BOOM 4, MEGABOOM 4, EVERBOOM, EPICBOOM, and HYPERBOOM speakers or even pair with previous generation BOOM speakers (in stereo or party mode configurations). It's worth double-checking if your speaker is compatible before attempting this, though. There's a graphic EQ and presets for sound profile adjustment, too. You can see the app in action in our demonstration video.

This speaker can't be used with a wired connection. It's USB-C input is used only for charging.

The Bluetooth connectivity is great. Latency with both Android and iOS devices falls within good levels, so you're unlikely to experience lip-sync issues between the audio and video if you use this speaker to soundtrack movies or TV shows. Sadly, there's no multi-device pairing, so you'll have to disconnect from one device to use another.