What We Like

What We Don't Like

JBL has been pretty pioneering in providing high quality audio equipment without the kind of outlandish price tag which you might come to expect for the quality. Wireless, as we know, is a whole other ball game, so let’s see.


Available in four color variations (blue, white, black, and red), the Synchros E40BTs have an interesting look. It sounds a little disparaging to say that they look like toy headphones, but they kind of do. And that isn’t in a bad way. They don’t look cheap, but they do look incredibly simple and minimalist; more like someone’s idea or drawing of a pair of headphones than the actual headphones themselves. Whichever way you sling it, though, this is a tidy, attractive design.

Featuring an on-ear (rather than over-ear) form factor, the design is comprised largely of plastic with faux leather padding on the ear cups themselves. The logo is displayed prominently (maybe a little too prominently? Who’s to say.) on the earpieces, and this is about as complex as the design ever gets.

The cups do fold inwards to flatten down the model for transit, but there is little mobility when they’re unfolded and on your ears. The net result of this is that the fit, while undeniably comfortable, is a little inflexible and rigid. It’s not a big thing, but may affect some.


You’re pretty unlikely to find a pair of wireless headphones at the $100 mark which do not feature some kind of button controls and an integrated mic. In the case of the Synchros E40BTs, the controls can be found on the right ear cup. You click the pad up and down to adjust volume, and clicking left allows you to manage calls, play and pause, or talk to Siri (or Cortana, or the other ones).

A pretty interesting, albeit niche, feature is also included in the remote control section. Clicking right activates JBL’s ShareMe functionality which shares the audio signal coming into the headset from whatever is paired with it with any other JBL wireless devices in range. There aren’t a ton of use cases for this in case your BFF happens to have the same headset, but it’s definitely handy to have if you can actually find a use for it.

Charging is via a USB cable and takes about three hours to complete a full charge. You’ll also find a headphone jack which allows you to connect a cable if you want to switch to wired mode to preserve the battery (or because it has died on you mid-jam).


Connectivity is solid, and there were no noticeable issues in our tests with which to report back. Pairing was easy and fast, and the range was better than advertised. Battery life is a thoroughly impressive 16 hours when it comes to continuous playback and a whopping 24 hours of talk time. Combining this with the ability to switch to a wired playback mode, there is basically no excuse for the music ever to stop.

Across the board, the E40BTs do impress for relatively affordable wireless headphones. The sound is best described as clear, and although it lacks a little in the bass response this is more than made up for by the fidelity of, in particular, the mid tones. You have a lot of control over the playback volume–these things can go surprisingly loud–, but there is some small but noticeable distortion when maxing out the levels. Because of the form factor, you’ll also experience some audio leakage at higher volumes. This is unlikely to be much of an issue, but it’s worth taking into consideration nonetheless.

The Rumble:

With an extremely impressive battery life, an attractive, simple design, and all the features you could expect at this price point, JBL has delivered well with the Synchros E40BTs. Sound quality is good, and wired mode is always a plus.