From an excellent in-ear fit and waterproof design to a user-friendly app that allows for a bass bonanza or a fairly accurate, flat sound signature, the Jaybird X4 earphones are a notable step forward in the series.

Powerful audio performance that is completely customizable using the app's EQ; Excellent in-ear fit; Waterproof

Short; proprietary charging cable

The X4 is a further refinement of Jaybird's sport earbuds, and both a solid and cheaper alternative to Apple's Powerbeats3.

I'd always used standard ear buds for running previously but these take things to the next level for me. The sound quality is very good and you can customise it to suit how you like it to sound via the app so you have full control over the EQ/soundstage which was brilliant, took a bit of tweaking...

I have only used these headphones for a couple of weeks and very impressed so far. Easy to pair, easy to use, good clean bass, and does not slip out when I sweat.

Jaybird's X series has held a position among our favorite Bluetooth earphones for over five years now. Priced identically to their predecessors at $129.99, the company's new X4 earphones bring some new tricks to the table. The waterproof in-ears feature exclusive-to-Jaybird Comply Ultra foam eartips, redesigned interchangeable eartips and fins, and a new cable cinch management system. If these sound like somewhat incremental upgrades, they are, but when your product is among the best, not every iteration needs to reinvent the wheel. In terms of audio quality, Jaybird's free app offers customizable EQ, so you can lock in whatever sound signature you desire, from pounding bass to austere flat response. The X4 earphones are incredibly versatile, and earn our Editors' Choice for exercise-focused in-ears. Design Available in black, glacier white, or jade, all X4 models feature metallic accents and can be worn over the ear, with the cable behind the neck, or with the cable dropping belo...

The wireless, exercise-focused Jaybird X4 earphones are supremely versatile, delivering booming bass or balanced audio depending on your EQ preferences.

Powerful audio performance that is completely customizable using the app's EQ; Excellent in-ear fit; Waterproof

Short; proprietary charging cable

Jaybird is back to its old ways with the release of the Jaybird X4. These are some of the best-wired Bluetooth headphones on the market and should definitely be considered by anyone, but especially if you are a frequent gym-goer. The sound is great and the design is familiar, yet comfortable.

The new standard.

Decent sound; IPX7 rating; Better fit than previous versions

Kind of uncomfortable; Mids are lacking in clarity; Battery life is good; but still falls just short of the claimed 8 hours

The Jaybird X4 sports headphones have a lot going for them. They're well-designed and sound good, plus they're pretty good at staying nicely in your ears. The app is a nice touch too - allowing you to customize the frequency response to your preferences.

If you were to ask me to suggest a pair that will please most people-no matter their musical tastes or how they intend to use them-I'd recommend Jaybird's X4 wireless sports earphones .

IPX7: can be submerged in one meter of water for 30 minutes; Sound great under most circumstances; MySound companion app allows for EQ adjustment; Ship with Comply foam ear tips; 10-minute quick charge provides an hour of listening

Proprietary charging cable required; Audio becomes muddy at maximum volume; Audio call quality could be better