Under Armour True Wireless Flash by JBL Review

Under Armour True Wireless Flash by JBL Review

JBL usually produces the best fitting sports earphones on the market. So, I was very excited to discover their latest sports true wireless earphones, which were designed in partnership with Under Armour. Are these buds sure to stay in place even for the heaviest sweaters? And can we expect JBL’s usual bassy sound signature? Let’s find out in this Under Armour True Wireless Flash by JBL Review.

Under Armour True Wireless Flash by JBL Review

IN the BOX

Under Armour True Wireless Flash by JBL Review


The Flash earbuds are, by far, the most secure fitting true wireless earphones I’ve ever tested. The earpieces employ “Sport Flex Fit” rubber covers with ergonomic tips that sit in the contours of your ears. These rubber parts come in three different sizes (in addition to the different sized ear tips), so you shouldn’t have trouble finding the right fit. The sound isolation is fantastic too, and it probably beats any noise-cancelling earphones I’ve tried.

Under Armour True Wireless Flash by JBL Review

Under Armour True Wireless Flash by JBL Review

Under Armour True Wireless Flash by JBL Review


Functionality and Controls

Because the fit provides such great sound isolation, JBL has included an ambient and talk through mode. Both of these functions let in outside sound and allow to more easily interact with the world around you. They call it “bionic hearing.” Great for ordering coffee or biking in traffic. All of the controls can be activated from the buttons on the earpieces, including, play/pause, track skipping, calls, and voice assistants. The only control that’s missing is volume. Luckily, reaching for the volume button on your phone burns 3 calories.

One feature that makes these buds ideal for sports is the IPX7 waterproof rating. These buds can take some splashes and serious sweat. The charging case is heavy and solid too, so it should withstand a lot of use. (I accidentally pushed my charging case off the desk and it handled the impact fine). I wish the case was a little smaller. But at least you’re less likely to lose it.

Under Armour True Wireless Flash by JBL Review

Under Armour True Wireless Flash by JBL Review


The Under Armour Flash offers a total battery life of 25 hours, and it allows for 5 hours of use before you have to put it back in the charging case. All in all, it should take about 2 hours to fully charge. The Flash comes with a Micro-USB to USB cable for charging.

Under Armour True Wireless Flash by JBL Review

Under Armour True Wireless Flash by JBL Review

Bluetooth Version

It’s interesting that JBL has stayed with the older Bluetooth 4.2 version instead of upgrading to Bluetooth 5. That being said, I had no problems with dropped signals, and transmission was solid overall.

Call Clarity

Call clarity isn’t bad, but I’ve heard better for the price. The microphone isn’t very sensitive, but it was enough to carry out a clear conversation. And there was little ambient interference in noisy environments.



The Flash produces the fat and juicy lows that make JBL famous. The forward leaning bass brings plenty of punch to pop and hip-hop tracks. You’ll also hear a ample warmth from these buds, which brings out the richness in big rock and pop-rock tracks. But classical and jazz fans should note that the Flash is not a critical listening headphone. And testing out some cellos, there was more smoothness than transparency. Still, the sound profile remained pleasing to the ears even with the latter genres.


You can expect present and well-balanced mids. The low mids are overshadowed by the bass frequencies at times. But vocals in the upper mids avoid sitting too far forward. As a result, you’ll get a full-bodied feel when listening to rock and pop-rock choruses without any harshness from the higher registers of this range. The separation could be a little cleaner, and acoustic instruments like guitars music lacked a little nuance and definition. So, these buds are most ideal for modern genres.


Again, you can expect more smoothness than detail when listening to strings in this range. But listening to pop, percussion was snappy while avoiding any fatiguing sizzle. So, folks with ears that are sensitive to high frequencies should be safe with these buds. At the same time, you can still expect a lot of flavor in the highs. I played my girl, Rihanna, for example. And her vocals were conveyed with plenty of color, adding to the lushness of the track.


Although, the Flash doesn’t present a particularly spacious soundstage, there was some dimension there. Gradations in depth felt precise, and there was enough height there to give it a somewhat 3D feel.


With solid sound and a crazy good fit, these true wireless buds are a good deal, especially considering that they’re cheaper than the AirPods, which don’t fit as snugly and fail to isolate sound. If you’re worried about your earpieces staying in your ears and/or you tend to sweat buckets, the True Wireless Flash might be the safest purchase on the market. Add to that some great build quality, and the Flash proves to be a winner.

You can find these JBL earphones for the best price here:

Audio 46 (Use our promo code, “majorhifi” to get 10% off)


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Gabby is a composer, songwriter and music producer who has worked in the music, film, and commercial industries for too long. You can hit Gabby up at gabby@majorhifi.com.