Reviewed: Under Armour x JBL Flash X Headphones

We look at a pair of sports headphones that are supposed to help increase safety with some very cool new tech.


A super nice-sounding pair of in-ear headphones with two bits of tech that are meant to help keep you aware of your surroundings—to a mixed effect


Amazing sound for sports headphones

Great weather resistance

TalkThru tech is very cool

Incredibly good at isolating sound (if that’s what you’re looking for)

Almost infinite battery life


Incredibly good at isolating sound (if that’s what you don’t want)

Ambient Aware was very hit-or-miss

No volume buttons




Under Armour

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If you haven’t read anything else I’ve written about training outdoors with headphones on, then I’ll give you the quick spiel: I don’t like it. With the increase of distracted drivers (texting, mapping, dealing with homeschooled kids, their lives in general, etc.), it’s vital that you hear your surroundings when you’re riding or running on public roads/sidewalks. I’m not even a huge fan of headphones while on quiet trails, because that extra sense could be what prevents you from getting mowed over by a mountain biker or a horse or narrowly avoiding a rattlesnake (yes, all of those things have happened to me recently). That said, I have used open-ear headphones like Aftershokz—that use bone conduction to transmit sound and leave your ears wide open. But I don’t do that often, either. Knowing this, various headphone companies have used tech—usually via a clever reverse application of noise canceling—to try to help keep you aware while running or riding outside while still listening to their headphones. Hence why I was so interested to check out the Under Armour x JBL Flash X Headphones that not only have two bits of interesting awareness technology, but also a monstrous battery life.

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The Tech

Without diving too far into the nuts and bolts of the Flash X, JBL has two bits of technology that are intended to help with awareness. First, there’s “Talk Thru”—with a quick tap of the left ear bud, the headphones lower volume drastically and also activate a tiny mic on the outside to help actually bump up the sound around you. Since these are in-ear headphones, even if you just hit “pause” (an obvious solution if someone’s talking to you), you’ll still probably be unable to hear them and still need to remove a bud. This whole bud-removal process is super annoying. Talk Thru works very very well, and cuts the sound drastically while allowing you to hear anything happening around you much better than if you had just hit pause. The other bit of tech, Ambient Aware, is a little more complex, but the long and short of it is that you double tap the left ear bud (you can’t do this while in Talk Thru, by the way), and it’ll still maintain the same level of volume for your music, but it’ll also trip the external mic in an effort to beef up the sound around you as well, and let enough in to help keep you safe. This doesn’t work quite as well as Talk Thru, but we’ll get to that below.

The Good

First off, the battery for this pair of headphones is almost ridiculous. You can listen in Bluetooth mode for 10 hours, and when you’re not wearing them, you can put them in the included case to charge for up to 40 hours of playback time without plugging into a wall. No, JBL is far from the first ones to do this, but 40 hours is pretty crazy. A USB-C plug recharges the battery/case and headphones when necessary. As a close second favorite feature, these are by far some of the best sounding sports headphones I’ve heard. You get great bass response, super crisp mids and lows—all without the fatigue you might experience from something too piercing. As someone who listens to good headphones very regularly, I was actually surprised to hear new things on familiar songs. Here, music isolation is also very very good—for better or for worse. I also loved the handy Talk Thru function as something so simple but so necessary when you’re training indoors or out—tap the button, the volume drops, and the outside sound is beefed up. I could easily hear someone talking quietly to me without removing the buds or pausing my music. The form factor and design for the headphones themselves and the case are also pretty cool.

The Bad

Normally I hedge a little bit on this section with a title like “The Not-So-Good” or something like that, but because we’re talking about actual safety, I have to be a little more harsh. When it came to the Ambient Aware tech, it was useful in only very specific situations—which is not great for something that’s supposed to alert you to a sudden emergency. If it’s not consistent, then you won’t be ready for the unexpected. For me, when running at almost any speed in any situation except where the wind is at my back, I mostly heard wind coming through the headphones. Not only was this super irritating, but it also prevented any possibility of danger-indicating sounds from coming through. In fact, it made me less aware. That said, when I had the wind at my back or in certain walking situations, I could hear traffic above 30mph; but even in quiet neighborhoods, it was nearly impossible to hear cars below 30mph—and this is often when you’d need it most. In terms of riding, the wind situation was substantially worse and made the function nearly unusable. I don’t know how they’d fix this—cut out the wind, but nothing else—but it truly limited the usefulness of Ambient Aware. Though it’s a far far less important missing feature, the lack of volume buttons on the earbuds was pretty frustrating, as I had to adjust via my phone (yes, you must connect to an external device, they do not store music onboard).

Use Your Conclusion

So while I do have a pretty hefty “bad” category in this review, these headphones do serve a few big purposes: First, if you’re training indoors, and you often find yourself muting or stopping and starting your music, the Talk Thru feature is amazing. While you can’t swim with these, if you’re in the gym or at home running or riding stationary, it would be tough to find a better-sounding pair of super sweat-resistant Bluetooth headphones. On the other hand, if you’re looking to run or especially ride outdoors, I would not say these will increase your awareness, except in only very very rare occasions. These are a great pair of headphones for people who worry about audio quality, hate plugging things in, and still want to hear people/things around them on command, but they’re not a great fit for outdoor safety all the time.

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