Under Armour True Wireless Flash by JBL Review
Sergio Montana

Under Armour True Wireless Flash by JBL Review

For workout fans and not only.

JBL is pushing forward yet again and is looking to be a contender in the true wireless segment with its premium model in the UA True Wireless Flash, which is targeting the fitness-conscious user with its waterproof construction, bold sound performance, and ambient sound amplification technology. Let's see if these earphones have what it takes to stand out in a crowded sea of competitors.

In the box

The headphones come in a rectangular aluminum charging case with a dark grey Under Armour logo to indicate which side should face skyward. 

Also included are additional ear pads and documentation.


One quick look and there’s no denying that these are meant to be worn by fitness fanatics. They are very similar in design to the aging Jaybird Run earbuds, evident in how they too feature winged ear tips for a more secure fit in the ear. 

The UA True Wireless Flash earbuds are substantial and are meant to withstand all sorts of workouts thanks to the snug fit in the ear and IPX7 water-resistant construction.

When tested at the gym, they manage to remain in place even during workouts that involve intense motion – like running on the treadmill for long periods of time. Normally, the sweat and motion would be eventually too much for other earbuds, causing them to slowly become loose, but there are no issues with the UA True Wireless Flash. 

While we’re digging the sporty design of the UA True Wireless Flash, we’re not as enthused by the accompanying battery charging case. Quite simply, it’s bulky, oversized, and pretty ordinary by today’s standards. And it doesn’t do anything more than recharging the earbuds – so it can’t be used as a battery bank to charge other gadgets.

Software and Functionality

When they’re taken out of the battery charging case for the first time, the UA True Wireless Flash earbuds are automatically in pairing mode, which is indicated by the rapidly blinking red/blue LED light on the right earbud. They power off automatically when they’re placed into the charging case, but this can also be manually done by long-pressing the physical buttons on the outer edge of both earbuds.

In the event you need to pair them to a new device, all that’s needed is to power them off and then long-press the right earbud for approximately 5 seconds until the LED lights begin to blink – indicating they’re in pairing mode.

After getting the earphones connected to our smartphone, a Huawei Mate 20 Pro, there’s no additional software or app to download to access more advanced settings and modes. 


In testing out the UA True Wireless Flash’s connectivity, we’re satisfied that the earphones didn’t once drop the connection to our smartphone. As for the range, we’re equally impressed that they’re able to get over 10 meters in open spaces – while indoors they’re still able to retain connectivity through walls and closed areas upwards of around 6 meters, so adjacent rooms are pretty much the extent of their coverage.

For those of you wishing to use the UA True Wireless Flash for watching videos on the go, you may be disappointed to know that they exhibit some latency – both while streaming video and when playing files stored locally. The delay is about a half second at most, which may not seem all that much on paper, but when you’re watching a video and the audio coming out of the earbuds isn’t synchronized, it dilutes the experience. 


As we’ve mentioned, there’s a physical button on the outside edge of both earbuds. With the left one, we can switch between the TalkThru and AmbientAware modes by single- or double-pressing the button respectively. Both modes will mute the audio. TalkThru mode will also amplify voices to make for better conversation, while AmbientAware will do the same for ambient noise.

And lastly, long-pressing the button for a couple of seconds will initiate the connected device’s default voice assistant service.

When it comes to media playback controls, they’re mostly handled by the right earbud. Pressing down on the button will perform a pause/play function, while a double press achieves a track forward function. Unfortunately, there are no controls for track reverse or volume adjustment – so those functions can be accessed through your connected device.

Sound Quality

Skewing more towards the bassy side of the audio spectrum, the UA True Wireless Flash are well equipped in keeping users motivated while working out. Thankfully, the bass isn’t overpowering to the point where it would drown out audio in the higher ranges.

At louder volumes, it’s able to maintain their richness without yielding any sort of distortion. It helps, too, that the snug fit of the earbuds allows audio to funnel into the channel and directly into our ear – without any sort of degradation to the volume output.

Even though we’re relatively pleased by the audio performance, it would’ve been better for the UA True Wireless Flash to offer preset or custom equalizer settings. 

Battery Life

Battery life is better than average. In our testing, we were able to get 4.5 hours of battery life out of a full charge – while the battery charging case tacks on an additional four charges.

The 4.5 hours of battery isn’t too shabby, given that the average has been roughly 3 hours with most true wireless offerings. Those intending to use them during the gym for 1-hour sessions won’t have much to worry about when it comes to recharging them frequently.


Workout fanatics will undoubtedly want to consider the UA True Wireless Flash, which offer one of the best fits when it comes to staying in place during workouts – in addition to the bass-heavy performance. 

• Comfortable fit
• 4.5-hour battery life, up to 24-hour charging case
• Great passive noise isolation
• Fully waterproof
• Bulky charging case

• Audio lag with mobile video

JBL UA True Wireless FLASH Bluetooth Sports Earphones Waterproof Running HIFI Headphones with Charging Box Handsfree Call with Mic



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