JBL Synchros E40BT review

JBL's lower-end foray into Bluetooth headphones delivers stellar results

JBL Synchros E40BT review

TechRadar Verdict

Affordable without sacrificing too much quality, the JBL Synchros E40BT delivers quality Bluetooth sound and reliable battery life.


  • +

    Great sound for the price

  • +

    Long battery life

  • +

    Stylish color schemes

  • +

    ShareMe function


  • -

    Snug against the ears

  • -

    Flimsy build

  • -

    Aggressive branding

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It sure is handy to have a nice pair of Bluetooth headphones these days, what with a full arsenal of gadgets that you can pair with at a reasonable distance. The $99 (about £60, AU$110) JBL Synchros E40BT represents JBL's attempt to deliver a low-priced option that doesn't skimp too much on performance or style.

And luckily, it succeeds. While a little light on the bass and a bit snug on the ears, the E40BT cans offer a great all-around experience with the added perk of a signal sharing feature.

Design and build quality

These are on-ear headphones, and as such rest on the outsides of your ears without fully covering them. The padded cups are covered in a silky leatherette material – the same cushy substance can be found in the pillow pad that helps ensure the headphones rest comfortably atop your dome.

JBL Synchros E40BT review

While the basic design is relatively simple, there are some nice visual touches. Namely, there's the crosshatch texture on the ring surrounding the JBL logos, and the triangles on the hinge where the earcups fold in for portability.

The logos are a bit too prominent, however, and the black-with-silver color scheme I received isn't terribly exciting. The white-and-gray version looks slick, on the other hand.

Also on E40BT's available color spectrum, the red headset really pops, and the black pair of cans with purple accents adds just enough subtle flash to make an impression.

JBL Synchros E40BT review

While the cups fold in via 3D hinges to flatten the overall shape for storage and travel, they are sadly fixed in place when on your ears; there's no give in the fit to allow the cups to mold to the shape and position of your ears.

As a result, the fit feels a little rigid. After about 30 minutes of use at a time, I'd find myself nudging and adjusting the headphones, hoping for a small change. It's not the most uncomfortable a pair of headphones have ever felt, but it's less comfortable than I hoped it would be for long stretches. Admittedly though, that tends to come with the territory with on-ear headphones.

And while it makes sense given the price, the build quality does feel a little cheap in a couple of spots. The adjustable segment where the cups attach to the headband feels loosely connected, and it seems like you could crack it off with ease – not that I dared venture down that broken-plastic path.

JBL Synchros E40BT review

Audio performance

For simple, affordable wireless headphones, the E40BT make a fine impression. The sound is clear and punchy, with solid mid-range performance. However, it's just a bit lacking when it comes to bass output.

That was especially noticeable when listening to hip-hop. Kanye West's "Yeezus" still sounded appropriately grimy with its ear-slaying effects, but the thump was just a bit subdued. But, switching to something like Chvrches's "The Bones of What You Believe," the soaring synths sounded totally superb on these affordable cans.

And the E40BT can get plenty loud if you want it – surprisingly so, actually – but the output starts to get a bit muddled if you're cranking the feed. That's no shock, since these aren't high-end drivers, but it's not really a problem. If you do like your audio deafeningly loud, just note that the headphones blast out a lot of excess noise to others nearby.

JBL Synchros E40BT review

You can't see the microphone, but the E40BT works just as well for taking calls, with clear voice reception pumping into the ears. What's better, those on the other end of the call reported no audio issues with what I sent back through the mic.

Features and battery life

Button controls are handily found on the right cup, with the big JBL saucer serving as a directional pad of sorts. You can click up or down for volume adjustments, plus left for the multi-function button, which lets you skip tracks and manage calls alike.

The right button, meanwhile, triggers an interesting feature on the E40BT: ShareMe, which lets you share an audio signal from a paired device with another compatible JBL headset. That seems a really niche feature, as everyone seems to have their own devices these days. At least it's a neat option if you have another pair of E40BT or E50BT headphones available.

Battery life on the E40BT is advertised at an impressive 16 hours (and up to 24 hours of talk time), and that seems about right based on the hours and hours I listened without interruption across several days. JBL is keen on preserving battery life, which means the headphones will turn off after only a few minutes of idling.

They charge easily via a USB cable that plugs into the headphone jack on the headset (a full charge takes about three hours), and that same port can be used with a male-to-male headphone jack for wired playback should the battery run thin.


There's an incredible array of expensive Bluetooth headphones to choose from, but if you're seeking something affordable that doesn't sacrifice too much quality in the process, the JBL E40BT should do the trick.

The on-ear fit is a little too snug for my liking, and can make longer sessions a little restless, but the sound quality is quite good, the battery life is stellar, and the design aesthetics look great (in the right color combination.) If you really don't want to spend more than 100 bucks on a pair of headphones, definitely take a long look right here.