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JBL UA True Wireless Flash

Usage Ratings - Version 1.2
Mixed Usage
Critical Listening
Type : In-ear
Enclosure : Closed-Back
Wireless : Truly Wireless
Noise-Cancelling : No
Mic : Yes
Transducer : Dynamic

The JBL Under Armour True Wireless Flash are great sports headphones that stand out thanks to their good audio reproduction and their rugged build quality. They are versatile for a wide variety of music genres, are sweat-proof and waterproof, and their bulky design feels durable for most intense sports. Their fit is good and fairly comfortable, on top of sealing off ambient noise, making them well-rounded for most everyday uses. Unfortunately, they won’t be great for watching videos due to their very high latency, and some may feel like 4 hours of battery life isn’t enough for a single charge. On the upside, they also offer a 12-month subscription for Under Armour’s fitness app called MapMyRun.

Test Results
Design 7.9
Sound 7.1
Isolation 8.2
Microphone 6.5
Active Features 4.7
Connectivity 2.8
  • Durable and stable fit for sports.
  • Good audio reproduction.
  • Great passive isolation performance.
  • Very high latency.
  • In-ear fit might not be for everyone.

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UA True Wireless Flash


The JBL Under Armour Flash are well-designed truly wireless in-ear headphones. They are fairly comfortable and fit securely inside your ears thanks to their stability fins. Their design is quite bulky, but they don’t hurt your ears too much after wearing for them a while. They are quite breathable and portable, which is great for sports. They are well-built and feel dense and sturdy, on top of being rated IPX7 for water and sweat resistance. They come with a nice metal hard case, but it's slightly bulkier than most truly wireless cases.


The UA Flash have a bulky in-ear design that protrudes quite a bit out of the ears. They look like sports earbuds with their stability fins, and have Under Armour logos on the back of the buds, which act as buttons. They only come in a single all-black color scheme, with a small red accent.

7.0 Comfort
Weight : 0.04 lbs
Clamping Force
0 lbs

The JBL UA True Wireless Flash are fairly comfortable truly wireless headphones. They are quite lightweight even if they have a bulky design. They fit nicely inside the ears and come with a few options for tip and fin sizes, to help you find the most comfortable fit. Some people may not like the in-ear fit and may feel ear fatigue after a while, but these don’t enter the ear canal as deeply as traditional in-ears thanks to their angled design.

6.6 Controls
Ease of use : Decent
Feedback : Decent
Call/Music Control : Yes
Volume Control : No
Microphone Control : Yes
Channel Mixing
Noise Canceling Control : N/A
Additional Buttons : Voice enabled controls

The JBL Under Armour True Wireless Flash have a fairly simple and easy-to-use control scheme. Each bud has an Under Armour logo that is also a button. On the right ear, you can play/pause your music and skip tracks, but you can’t rewind or go to the previous track. You can also manage calls and mute your microphone. On the left earbud, you can cycle through their ambient and talk-through modes. A single tap will put you their talk-through mode, which greatly reduces your music level and lets you hear surrounding noise very well. A double tap will put you in their ambient mode, which will allow you to hear your surroundings, but you’ll still be able to hear your music fairly loud.

Unfortunately, you can’t jump from one mode to another and need to go back to their normal listening mode before making another input. You can also trigger your device’s voice assistant with a 2s hold on the left earbud. Unfortunately, they don't have any volume controls like other sports truly wireless headphones like the Jabra Elite Active 65t or the Bose SoundSport Free.

9.2 Breathability
Avg.Temp.Difference : 0.8 C

Like most in-ears, the JBL UA Flash True Wireless are very breathable headphones, even if their design is quite bulky. They block most of the airflow inside your ear canal, but their in-ear design will still be breathable and won’t trap too much heat. You shouldn’t feel a big difference in temperature when wearing these during your workouts, and they won’t make you sweat more than usual.

9.2 Portability
L : 1.5 "
W : 1.4 "
H : 1.3 "
Volume : 3 Cu. Inches
Transmitter required : N/A

Like most truly wireless headphones, the JBL UA True Wireless Flash are very portable. The buds are a bit bulkier than average, but they will still easily fit inside pockets or a bag. They are easy to carry around and come with a nice hard case that is fairly portable too.

8.0 Case
Type : Hard case
L : 3.3 "
W : 1.6 "
H : 1.2 "
Volume : 6 Cu. Inches

These headphones come with a hard charging case that protects the headphones well against physical damage, water exposure, and scratches. The case is a bit bulky, but should still fit in most pockets or a bag. It has a high-end feel as it is heavy and made from solid materials. Unfortunately, it has some minor flaws. The tray wiggles around when fully extended and the earbuds sometimes clip the top of the case when pushed back in. The case is said to be waterproof, and you also get LEDs for battery level indication.

8.0 Build Quality

The Under Armour Flash True Wireless from JBL are very well-made truly wireless headphones. The buds are dense and feel solid enough to survive a few accidental drops without too much damage. They feel like premium headphones, similar to the Sennheiser Momentum True Wireless. Their metal case is also very well-made and feels sturdy. These headphones are rated IPX7 for sweat and water resistance.

8.0 Stability

The JBL UA True Wireless Flash are very stable and will be suited for most sports. They are somewhat bulky, but still sit nicely inside the ears and don't move much, even when exercising. They have a few size options for tips and fins, which helps you find the perfect fit. You should be able to do most sports with these without them popping out of your ears. Also, their truly wireless design means you won’t have to worry about any cables.

Detachable : N/A
Length : N/A
Connection : N/A

The JBL UA Flash don’t come with an audio cable, as expected, and come with a short and flat micro-USB to USB charging cable.

Headshots 1
Headshots 2


The JBL Under Armour True Wireless Flash are decent-sounding closed-back in-ear headphones. They have an excellent, extended, and powerful bass, a very well-balanced mid-range, and a good treble. However, their bass is slightly thumpy, though some may prefer this. Vocals and lead instruments are accurately reproduced, but they could feel ever so slightly nudged to the back of the mix for some. Additionally, their treble is slightly uneven on S and T sounds, so vocals and leads may feel lacking in detail and brightness. Overall, these headphones have good audio reproduction and are very versatile for a wide variety of music genres.

9.3 Bass
Std. Err.
1.05 dB
Low-Frequency Extension
10 Hz
1.82 dB
0.92 dB
0.64 dB

The bass performance of the JBL True Wireless Flash is very impressive. The LFE (low-frequency extension) is down to 10Hz, which is excellent. Their response is virtually flawless and follows our target curve very well. It has a small 2dB overemphasis in the low-bass range, which results in a slight excess of thump and rumble, which fans of bass-heavy music may prefer. Overall, their bass is amazing and has the right amount of punch and body, without being overly done.

9.0 Mid
Std. Err.
1.38 dB
0.24 dB
-1.49 dB
1.15 dB

Their mid-range is also excellent. The response throughout the range is very well-balanced and flat, which results in an accurate reproduction of vocals and lead instruments. There is a small dip in mid-mid, which will slightly nudge vocals and leads to the back of the mix, but this will barely be noticeable for most.

7.7 Treble
Std. Err.
3.75 dB
-1.07 dB
-2.66 dB
-0.32 dB

The JBL UA True Wireless Flash have a good treble performance, but the response is slightly uneven. There is a broad dip in the low-treble, which will negatively affect the brightness and detail of vocals and details. The graph also shows a few bumps in higher frequencies, resulting in some S and T sounds being too sharp and piercing for some, while others will lack detail. However, not everyone hears treble frequencies the same way, so your experience could vary.

9.0 Frequency Response Consistency
Avg. Std. Deviation
0.21 dB

The frequency response consistency is excellent. If the user can achieve a proper fit and an air-tight seal using the assortment of tips that come with the headphones, then they should be able to get consistent bass and treble delivery every time they use the headphones.

8.9 Imaging
Weighted Group Delay
Weighted Amplitude Mismatch
Weighted Frequency Mismatch
Weighted Phase Mismatch

The stereo imaging is excellent. Their weighted group delay is at 0.16, which is very low. The group delay graph also shows that the entire response is well below the audibility threshold. This ensures a tight bass and a transparent treble reproduction. Also, the L/R drivers of our test unit were well-matched in frequency, amplitude, and phase response. This is important for the accurate placement and localization of objects (voices, instruments, video game effects) in the stereo image. Note that these results are only valid for our unit and yours may perform differently.

1.0 Soundstage
PRTF Accuracy (Std. Dev.)
PRTF Size (Avg.)
PRTF Distance
Acoustic Space Excitation
Correlated Crosstalk
0.0 dB

The soundstage is poor. This is because creating an out-of-head and speaker-like soundstage is largely dependent on activating the resonances of the pinna (outer ear). The design of in-ears and earbuds is in such a way that fully bypasses the pinna and doesn't interact with it. Also, because these headphones have a closed-back enclosure, their soundstage won't be perceived to be as open as that of open-back earbuds like the Apple AirPods 2 2019, Google Pixel Buds, or the Bose SoundSport Free.

7.1 Total Harmonic Distortion
Weighted THD @ 90
Weighted THD @ 100

The harmonic distortion performance of these headphones is decent. The THD graph shows limited amounts in the bass range, which is great. However, it stays at the same level throughout the range, which is high for the mid and treble ranges. There are also bumps around 1kHz and 4.5kHz, which could make these frequencies a bit harsh and impure.



The JBL UA True Wireless Flash have good isolation performance, even without an ANC feature. They passively block a decent amount of ambient noise and will be suitable for most environments like your daily commute or at the office. They barely leak, making them excellent headphones in quieter environments where you want to mask more noise by raising your audio volume without bothering people around you.

7.4 Noise Isolation
Isolation Audio
Overall Attenuation
-25.43 dB
-10.5 dB
-20.35 dB
-46.14 dB
20.52 dB

The JBL UA True Wireless Flash have a decent noise isolation performance. They only passively block noise as they don’t have an ANC feature, but they still do a better job than some ANC headphones. In the bass range, occupied by the rumble of airplane and bus engines, they reduce the noise by about 11dB, which is decent. However, this is rather impressive for in-ears and more than what some active noise cancelling headphones achieve. In the mid-range, important for blocking out speech, they achieved 20dB of isolation, which is very good. In the treble range, occupied by sharp S and T sounds and fan noises like A/C systems, they achieved about 46dB of isolation, which is excellent.

9.8 Leakage
Leakage Audio
Overall Leakage @ 1ft
22.68 dB

The leakage performance is excellent. These in-ears do not leak much, so you don't need to worry about disturbing people around you unless you are blasting your music in a very quiet room. With the music at 100dB SPL, the leakage at 1 foot away averages at 23dB SPL and peaks at 29dB SPL outside of the bass range, which is noticeably quieter than the noise floor of an average office.



Detachable Boom

The JBL UA True Wireless Flash have an okay integrated microphone. In quiet environments, speech recorded or transmitted with this mic will sound relatively thin, muffled, and lacking in detail. In noisy situations, it will struggle to separate speech from ambient noise, even in moderately loud environments such as a busy street.

6.6 Recording Quality
Recorded Speech
265.23 Hz
FR Std. Dev.
2.81 dB
3466.89 Hz
Weighted THD
35.93 dB

The recording quality of the microphone is okay. Speech recorded or transmitted with the microphone will sound thin and muffled. This is due to LFE (low-frequency extension) being at 265Hz and the HFE (high-frequency extension) being at 3.5kHz. However, the limited high-frequency extension is a limitation of the Bluetooth protocol and is a problem with all Bluetooth microphones. However, speech will still be decently intelligible with this microphone in quiet environments.

6.3 Noise Handling
Speech + Pink Noise :
Speech + Subway Noise :
15.92 dB

The microphone is mediocre at noise handling. In our SpNR test, it achieved a speech-to-noise ratio of 16dB, indicating that it's best suited for quiet environments. But it won't be ideal for moderate and loud environments, as it will have difficulty fully separating speech from ambient noise.


Active Features

The JBL UA Flash have a decent battery life for truly wireless headphones, but they won’t be suitable to use during long flights or a full workday. You’ll get over 4 hours of continuous playback, but they’ll take you more than an hour to charge, which isn't ideal. They don't have a dedicated app for customization, but they come with an included 12-month subscription for one of Under Armour’s fitness apps, MapMyRun.

5.3 Battery
Battery Type
Battery Life
4.2 hrs
Charge Time
1.5 hrs
Power Saving Feature
Audio while charging
Passive Playback

The JBL UA True Wireless Flash offer just over 4 hours of continuous playback with one charge, which is about average for most truly wireless headphones. They take about an hour and a half to fully charge and you can expect about 20 additional hours of playback from the case, according to the specs sheet. Unfortunately, they don’t have a smart power-saving feature, so be sure to turn the headphones off or to put them back in their charging case if you’re not using them.

0 App Support
App Name : N/A
iOS : N/A
Android : N/A
Mac OS : N/A
Windows : N/A
ANC control
Mic Control : N/A
Room effects
Playback control
Button Mapping : N/A
Surround Sound : N/A

These headphones don’t have a dedicated companion app for customization options, but when buying them, you get a 12-month subscription code to Under Armour’s MapMyRun fitness app.



The JBL Under Armour Flash are truly wireless headphones that, as expected, can’t be used passively in any way. They connect to your source via Bluetooth but can only be used with one device at a time. They come with a charging case that offers about 20 additional hours of playback time, but it doesn’t offer any inputs. They have amazing wireless range, but their latency is very high, which won’t be good for watching video content and gaming.

6.0 Bluetooth
Bluetooth Version
Multi-Device Pairing
NFC Pairing

The True Wireless Flash are Bluetooth compatible, but can’t be connected to multiple devices at the same time. This means you won’t be able to switch from your work computer and your phone. They also don’t support NFC for a quicker and easier pairing procedure.

0 Wired
OS Compatibility
Analog Audio
USB Audio
PS4 Compatible
Xbox One Compatible
PC Compatible

Like expected, the JBL Under Armour True Wireless Flash headphones can’t be used wired.

2.1 Base/Dock
Charging Case
Optical Input
Line In
Line Out
USB Input
RCA Input
PS4 Compatible
Xbox One Compatible
PC Compatible
Power Supply
Dock Charging

These truly wireless headphones come with a hard charging case that has a USB input to power the case, but doesn’t have any other inputs. It offers about 20 additional hours of battery life, according to the specs sheet.

9.0 Wireless Range
Obstructed Range
50 ft
Line of Sight Range
176 ft

The wireless range of the JBL UA Flash is amazing. They have a good line of sight range and an excellent obstructed range with about 50ft. You’ll be able to leave your Bluetooth source at one spot and move around in a small office or apartment without too many problems. However, wireless range is dependent on your device’s signal strength and many other factors, so your results may differ.

0 Latency
Default Latency
386 ms
aptX Latency
aptX(LL) Latency

The latency of the JBL UA Flash is very high. It is noticeably higher than most Bluetooth headphones and most people will see an important delay between audio and video. This means these headphones shouldn’t be used for watching videos or gaming.

In the box

  • JBL UA True Wireless Flash headphones
  • Charging case
  • 3x fin sizes
  • 3x tip sizes
  • USB to micro-USB charging cable
  • Manuals
  • 12-month subscription code for MapMyRun app

Compared to other Headphones

The JBL UA True Wireless Flash are great sports headphones that set themselves apart by their great build quality and audio reproduction. They are also quite comfortable for in-ears. However, their latency is very high, and some may feel like 4 hours of battery life isn’t enough. See our recommendations for the best wireless Bluetooth earbuds for running and working out, the best Bluetooth earbuds, and the best true wireless earbuds.

Bose SoundSport Free Truly Wireless

The JBL UA True Wireless Flash are better headphones than the Bose SoundSport Free Truly Wireless for most. They are more versatile thanks to their closed-back design that isolates well against ambient noise. They’ll be a better option for commuting, but as sports headphones, it comes to preference. Outside runners might prefer the semi-open design of the Bose to stay aware of their surroundings. Their earbud design is also a bit more comfortable, and they have better sound quality and a slightly better battery. On the other hand, you’ll get better range with the Under Armour Flash and they have a better microphone for calls. Their case is also more portable and sturdier, on top of being waterproof.

Jabra Elite Sport Truly Wireless

The JBL UA True Wireless Flash are better sports headphones than the Jabra Elite Sport Truly Wireless. They are more comfortable and more stable for most sports. They also have a better audio reproduction and are also more versatile for different uses, thanks to their better isolation performance. On the other hand, they don’t have volume controls like the Elite Sport do, which may be a deal-breaker for some. The Jabras also have a companion app, although the options and controls are limited. Also, our Jabra Elite Sport Truly wireless unit had a noticeable mismatch between the drivers.

Jaybird Run XT Truly Wireless

The JBL UA True Wireless Flash and the Jaybird Run XT Truly Wireless are both great sports headphones, but the JBL UA Flash might have a small edge over the Jaybirds for people who want great performance out of the box. They have a better default sound profile, but they don’t have an app with an EQ that can let you customize their sound signature like the Jaybird. The Under Armour headphones also feel slightly better built, especially their case. On the other hand, you’ll get a battery performance out of the Jaybird, but their control scheme is more limited and harder to use as you need to push the buds inside your ear canal even more, which can be uncomfortable.

Sony WF-SP700N Truly Wireless

The JBL UA True Wireless are better headphones than the Sony WF-SP700N Truly Wireless. They have better audio reproduction, are more stable for sports, and even if the Sonys are ANC headphones, the JBL UA Flash have a better isolation performance. Their control scheme is easier to use too and their build quality feels more high-end, on top of being rated IPX7. They also have about twice the battery life of the WF-SP700N. Overall, the JBL UA Flash are better in almost every aspect, but they don’t support NFC like the Sony do.


7.1 Mixed Usage
Decent for mixed usage. The JBL True Wireless Flash have good audio reproduction for in-ears and their small design is easy to carry around in your commute or at the gym. They also create a good seal in your ears, which isolates a good amount of ambient noise, which is good for public transit or at the office. They are designed as sports headphones thanks to their stability fins and waterproof build. They don’t have the longest battery life for flights or a normal workday, but they’ll be fine for working out. However, their latency is very high and they shouldn’t be used for watching video content and gaming.
7.2 Critical Listening
Decent for critical listening. These in-ears have a good audio reproduction with excellent bass range and mid range, and a good treble. Their bass is slightly thumpy, but some may prefer this. Vocals and leads are accurately reproduced, but they could feel ever so slightly nudged to the back of the mix for some. They are very versatile for a wide variety of music genres, but their treble is slightly uneven, which some may not hear. The in-ear fit might not be ideal for long critical listening sessions as some may feel some discomfort after a while.
7.5 Commute/Travel
Good for commuting. Their fit blocks out a good amount of ambient noise, including the deep rumble of bus and plane engines. They’ll be a good option for public transit, and since they barely leak you’ll be able to mask even more noise by raising your listening volume. Additionally, they are easy to carry around thanks to their portable design, but they don’t have a very long battery life on one charge, which won’t be the best option for long rides and flights.
8.1 Sports/Fitness
Great for sports. The JBL UA True Wireless Flash are designed for working out and will be suitable for most sports. They fit securely inside the ear and don’t move much when being active. Their stability fins will help to keep them in place and since you get different size options, you’ll be able to find the most stable one for you. They also don’t trap heat inside your ears, meaning you shouldn’t sweat more than usual when wearing these during your workouts.
7.3 Office
Decent for the office. The JBL UA True Wireless Flash do a great job at blocking out work environment noise like ambient chatter and fan noises like A/C systems. They also barely leak, so you shouldn’t bother surrounding colleagues with what you’re listening to. However, their battery life won’t be long enough for you to use them during a full workday; you’ll need to charge during lunchtime. Also, the in-ear fit might not be the best to wear for a few hours, as some may feel discomfort.
5.6 TV
Sub-par for TV. While the JBL True Wireless Flash have good audio reproduction, their latency is very high and won’t be suitable to watch video content. Most will notice a delay between audio and video, which can get frustrating. Also, their battery life won’t be ideal for binge-watching TV shows frequently, and not everyone will find the in-ear fit to be comfortable to use for hours.
4.8 Gaming
Bad for gaming. The JBL Under Armour True Wireless Flash headphones’ microphone won’t be good enough for online gaming and their latency is too high for video games. The delay between sound and video will be too noticeable and won’t be suitable for this use case. They also don’t have good battery life and overall will be a very poor choice for gaming.

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